wxWidgets: wxImage Class Reference

| Version: 3.2.2

Classes | Public Member Functions | Static Public Member Functions | List of all members
wxImage Class Reference
Class List by Category » Graphics Device Interface (GDI)

`#include <wx/image.h>`

Inheritance diagram for wxImage:
[legend]

## Detailed Description

This class encapsulates a platform-independent image.

An image can be created from data, or using wxBitmap::ConvertToImage. An image can be loaded from a file in a variety of formats, and is extensible to new formats via image format handlers. Functions are available to set and get image bits, so it can be used for basic image manipulation.

A wxImage cannot (currently) be drawn directly to a wxDC. Instead, a platform-specific wxBitmap object must be created from it using the wxBitmap::wxBitmap(wxImage,int depth) constructor. This bitmap can then be drawn in a device context, using wxDC::DrawBitmap.

More on the difference between wxImage and wxBitmap: wxImage is just a buffer of RGB bytes with an optional buffer for the alpha bytes. It is all generic, platform independent and image file format independent code. It includes generic code for scaling, resizing, clipping, and other manipulations of the image data. OTOH, wxBitmap is intended to be a wrapper of whatever is the native image format that is quickest/easiest to draw to a DC or to be the target of the drawing operations performed on a wxMemoryDC. By splitting the responsibilities between wxImage/wxBitmap like this then it's easier to use generic code shared by all platforms and image types for generic operations and platform specific code where performance or compatibility is needed.

One colour value of the image may be used as a mask colour which will lead to the automatic creation of a wxMask object associated to the bitmap object.

# Alpha channel support

Starting from wxWidgets 2.5.0 wxImage supports alpha channel data, that is in addition to a byte for the red, green and blue colour components for each pixel it also stores a byte representing the pixel opacity.

An alpha value of 0 corresponds to a transparent pixel (null opacity) while a value of 255 means that the pixel is 100% opaque. The constants wxIMAGE_ALPHA_TRANSPARENT and wxIMAGE_ALPHA_OPAQUE can be used to indicate those values in a more readable form.

While all images have RGB data, not all images have an alpha channel. Before using wxImage::GetAlpha you should check if this image contains an alpha channel with wxImage::HasAlpha. Currently the BMP, PNG, TGA, and TIFF format handlers have full alpha channel support for loading so if you want to use alpha you have to use one of these formats. If you initialize the image alpha channel yourself using wxImage::SetAlpha, you should save it in either PNG, TGA, or TIFF format to avoid losing it as these are the only handlers that currently support saving with alpha.

# Available image handlers

The following image handlers are available. wxBMPHandler is always installed by default. To use other image formats, install the appropriate handler with wxImage::AddHandler or call wxInitAllImageHandlers().

- wxBMPHandler: For loading (including alpha support) and saving, always installed.
- wxPNGHandler: For loading and saving. Includes alpha support.
- wxJPEGHandler: For loading and saving.
- wxGIFHandler: For loading and saving (see below).
- wxPCXHandler: For loading and saving (see below).
- wxPNMHandler: For loading and saving (see below).
- wxTIFFHandler: For loading and saving. Includes alpha support.
- wxTGAHandler: For loading and saving. Includes alpha support.
- wxIFFHandler: For loading only.
- wxXPMHandler: For loading and saving.
- wxICOHandler: For loading and saving.
- wxCURHandler: For loading and saving.
- wxANIHandler: For loading only.

When saving in PCX format, wxPCXHandler will count the number of different colours in the image; if there are 256 or less colours, it will save as 8 bit, else it will save as 24 bit.

Loading PNMs only works for ASCII or raw RGB images. When saving in PNM format, wxPNMHandler will always save as raw RGB.

Saving GIFs requires images of maximum 8 bpp (see wxQuantize), and the alpha channel converted to a mask (see wxImage::ConvertAlphaToMask). Saving an animated GIF requires images of the same size (see wxGIFHandler::SaveAnimation)

##

Library: wxCore
Category: Graphics Device Interface (GDI)

Predefined objects/pointers: wxNullImage

See also
  wxBitmap, wxInitAllImageHandlers(), wxPixelData

## Setters
void | SetAlpha (unsigned char *alpha=NULL, bool static_data=false)
| This function is similar to SetData() and has similar restrictions. More...
void | SetAlpha (int x, int y, unsigned char alpha)
| Sets the alpha value for the given pixel. More...
void | ClearAlpha ()
| Removes the alpha channel from the image. More...
void | SetData (unsigned char *data, bool static_data=false)
| Sets the image data without performing checks. More...
void | SetData (unsigned char *data, int new_width, int new_height, bool static_data=false)
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
void | SetLoadFlags (int flags)
| Sets the flags used for loading image files by this object. More...
void | SetMask (bool hasMask=true)
| Specifies whether there is a mask or not. More...
void | SetMaskColour (unsigned char red, unsigned char green, unsigned char blue)
| Sets the mask colour for this image (and tells the image to use the mask). More...
bool | SetMaskFromImage (const wxImage &mask, unsigned char mr, unsigned char mg, unsigned char mb)
| Sets image's mask so that the pixels that have RGB value of mr,mg,mb in mask will be masked in the image. More...
void | SetOption (const wxString &name, const wxString &value)
| Sets a user-defined option. More...
void | SetOption (const wxString &name, int value)
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
void | SetPalette (const wxPalette &palette)
| Associates a palette with the image. More...
void | SetRGB (int x, int y, unsigned char r, unsigned char g, unsigned char b)
| Set the color of the pixel at the given x and y coordinate. More...
void | SetRGB (const wxRect &rect, unsigned char red, unsigned char green, unsigned char blue)
| Sets the colour of the pixels within the given rectangle. More...
void | SetType (wxBitmapType type)
| Set the type of image returned by GetType(). More...
static void | SetDefaultLoadFlags (int flags)
| Sets the default value for the flags used for loading image files. More...

## Classes
class | HSVValue
| A simple class which stores hue, saturation and value as doubles in the range 0.0-1.0. More...
class | RGBValue
| A simple class which stores red, green and blue values as 8 bit unsigned integers in the range of 0-255. More...

## Public Member Functions
| wxImage ()
| Creates an empty wxImage object without an alpha channel. More...
| wxImage (int width, int height, bool clear=true)
| Creates an image with the given size and clears it if requested. More...
| wxImage (const wxSize &sz, bool clear=true)
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
| wxImage (int width, int height, unsigned char *data, bool static_data=false)
| Creates an image from data in memory. More...
| wxImage (const wxSize &sz, unsigned char *data, bool static_data=false)
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
| wxImage (int width, int height, unsigned char *data, unsigned char *alpha, bool static_data=false)
| Creates an image from data in memory. More...
| wxImage (const wxSize &sz, unsigned char *data, unsigned char *alpha, bool static_data=false)
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
| wxImage (const char *const *xpmData)
| Creates an image from XPM data. More...
| wxImage (const wxString &name, wxBitmapType type=wxBITMAP_TYPE_ANY, int index=-1)
| Creates an image from a file. More...
| wxImage (const wxString &name, const wxString &mimetype, int index=-1)
| Creates an image from a file using MIME-types to specify the type. More...
| wxImage (wxInputStream &stream, wxBitmapType type=wxBITMAP_TYPE_ANY, int index=-1)
| Creates an image from a stream. More...
| wxImage (wxInputStream &stream, const wxString &mimetype, int index=-1)
| Creates an image from a stream using MIME-types to specify the type. More...
virtual | ~wxImage ()
| Destructor. More...
int | GetLoadFlags () const
| Returns the file load flags used for this object. More...
Image creation, initialization and deletion functions
wxImage | Copy () const
| Returns an identical copy of this image. More...
bool | Create (int width, int height, bool clear=true)
| Creates a fresh image. More...
bool | Create (const wxSize &sz, bool clear=true)
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
bool | Create (int width, int height, unsigned char *data, bool static_data=false)
| Creates a fresh image. More...
bool | Create (const wxSize &sz, unsigned char *data, bool static_data=false)
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
bool | Create (int width, int height, unsigned char *data, unsigned char *alpha, bool static_data=false)
| Creates a fresh image. More...
bool | Create (const wxSize &sz, unsigned char *data, unsigned char *alpha, bool static_data=false)
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
void | Clear (unsigned char value=0)
| Initialize the image data with zeroes (the default) or with the byte value given as value. More...
void | Destroy ()
| Destroys the image data. More...
void | InitAlpha ()
| Initializes the image alpha channel data. More...
Image manipulation functions
wxImage | Blur (int blurRadius) const
| Blurs the image in both horizontal and vertical directions by the specified pixel blurRadius. More...
wxImage | BlurHorizontal (int blurRadius) const
| Blurs the image in the horizontal direction only. More...
wxImage | BlurVertical (int blurRadius) const
| Blurs the image in the vertical direction only. More...
wxImage | Mirror (bool horizontally=true) const
| Returns a mirrored copy of the image. More...
void | Paste (const wxImage &image, int x, int y, wxImageAlphaBlendMode alphaBlend=wxIMAGE_ALPHA_BLEND_OVER)
| Copy the data of the given image to the specified position in this image. More...
void | Replace (unsigned char r1, unsigned char g1, unsigned char b1, unsigned char r2, unsigned char g2, unsigned char b2)
| Replaces the colour specified by r1,g1,b1 by the colour r2,g2,b2. More...
wxImage & | Rescale (int width, int height, wxImageResizeQuality quality=wxIMAGE_QUALITY_NORMAL)
| Changes the size of the image in-place by scaling it: after a call to this function,the image will have the given width and height. More...
wxImage & | Resize (const wxSize &size, const wxPoint &pos, int red=-1, int green=-1, int blue=-1)
| Changes the size of the image in-place without scaling it by adding either a border with the given colour or cropping as necessary. More...
wxImage | Rotate (double angle, const wxPoint &rotationCentre, bool interpolating=true, wxPoint *offsetAfterRotation=NULL) const
| Rotates the image about the given point, by angle radians. More...
wxImage | Rotate90 (bool clockwise=true) const
| Returns a copy of the image rotated 90 degrees in the direction indicated by clockwise. More...
wxImage | Rotate180 () const
| Returns a copy of the image rotated by 180 degrees. More...
void | RotateHue (double angle)
| Rotates the hue of each pixel in the image by angle, which is a double in the range [-1.0..+1.0], where -1.0 corresponds to -360 degrees and +1.0 corresponds to +360 degrees. More...
void | ChangeSaturation (double factor)
| Changes the saturation of each pixel in the image. More...
void | ChangeBrightness (double factor)
| Changes the brightness (value) of each pixel in the image. More...
void | ChangeHSV (double angleH, double factorS, double factorV)
| Changes the hue, the saturation and the brightness (value) of each pixel in the image. More...
wxImage | Scale (int width, int height, wxImageResizeQuality quality=wxIMAGE_QUALITY_NORMAL) const
| Returns a scaled version of the image. More...
wxImage | Size (const wxSize &size, const wxPoint &pos, int red=-1, int green=-1, int blue=-1) const
| Returns a resized version of this image without scaling it by adding either a border with the given colour or cropping as necessary. More...
Conversion functions
bool | ConvertAlphaToMask (unsigned char threshold=wxIMAGE_ALPHA_THRESHOLD)
| If the image has alpha channel, this method converts it to mask. More...
bool | ConvertAlphaToMask (unsigned char mr, unsigned char mg, unsigned char mb, unsigned char threshold=wxIMAGE_ALPHA_THRESHOLD)
| If the image has alpha channel, this method converts it to mask using the specified colour as the mask colour. More...
wxImage | ConvertToGreyscale (double weight_r, double weight_g, double weight_b) const
| Returns a greyscale version of the image. More...
wxImage | ConvertToGreyscale () const
| Returns a greyscale version of the image. More...
wxImage | ConvertToMono (unsigned char r, unsigned char g, unsigned char b) const
| Returns monochromatic version of the image. More...
wxImage | ConvertToDisabled (unsigned char brightness=255) const
| Returns disabled (dimmed) version of the image. More...
wxImage | ChangeLightness (int alpha) const
| Returns a changed version of the image based on the given lightness. More...
Miscellaneous functions
unsigned long | ComputeHistogram (wxImageHistogram &histogram) const
| Computes the histogram of the image. More...
bool | FindFirstUnusedColour (unsigned char *r, unsigned char *g, unsigned char *b, unsigned char startR=1, unsigned char startG=0, unsigned char startB=0) const
| Finds the first colour that is never used in the image. More...
wxImage & | operator= (const wxImage &image)
| Assignment operator, using reference counting. More...
Getters
unsigned char * | GetAlpha () const
| Returns pointer to the array storing the alpha values for this image. More...
unsigned char * | GetData () const
| Returns the image data as an array. More...
unsigned char | GetAlpha (int x, int y) const
| Return alpha value at given pixel location. More...
unsigned char | GetRed (int x, int y) const
| Returns the red intensity at the given coordinate. More...
unsigned char | GetGreen (int x, int y) const
| Returns the green intensity at the given coordinate. More...
unsigned char | GetBlue (int x, int y) const
| Returns the blue intensity at the given coordinate. More...
unsigned char | GetMaskRed () const
| Gets the red value of the mask colour. More...
unsigned char | GetMaskGreen () const
| Gets the green value of the mask colour. More...
unsigned char | GetMaskBlue () const
| Gets the blue value of the mask colour. More...
int | GetWidth () const
| Gets the width of the image in pixels. More...
int | GetHeight () const
| Gets the height of the image in pixels. More...
wxSize | GetSize () const
| Returns the size of the image in pixels. More...
wxString | GetOption (const wxString &name) const
| Gets a user-defined string-valued option. More...
int | GetOptionInt (const wxString &name) const
| Gets a user-defined integer-valued option. More...
bool | GetOrFindMaskColour (unsigned char *r, unsigned char *g, unsigned char *b) const
| Get the current mask colour or find a suitable unused colour that could be used as a mask colour. More...
const wxPalette & | GetPalette () const
| Returns the palette associated with the image. More...
wxImage | GetSubImage (const wxRect &rect) const
| Returns a sub image of the current one as long as the rect belongs entirely to the image. More...
wxBitmapType | GetType () const
| Gets the type of image found by LoadFile() or specified with SaveFile(). More...
bool | HasAlpha () const
| Returns true if this image has alpha channel, false otherwise. More...
bool | HasMask () const
| Returns true if there is a mask active, false otherwise. More...
bool | HasOption (const wxString &name) const
| Returns true if the given option is present. More...
bool | IsOk () const
| Returns true if image data is present. More...
bool | IsTransparent (int x, int y, unsigned char threshold=wxIMAGE_ALPHA_THRESHOLD) const
| Returns true if the given pixel is transparent, i.e. either has the mask colour if this image has a mask or if this image has alpha channel and alpha value of this pixel is strictly less than threshold. More...
Loading and saving functions
virtual bool | LoadFile (wxInputStream &stream, wxBitmapType type=wxBITMAP_TYPE_ANY, int index=-1)
| Loads an image from an input stream. More...
virtual bool | LoadFile (const wxString &name, wxBitmapType type=wxBITMAP_TYPE_ANY, int index=-1)
| Loads an image from a file. More...
virtual bool | LoadFile (const wxString &name, const wxString &mimetype, int index=-1)
| Loads an image from a file. More...
virtual bool | LoadFile (wxInputStream &stream, const wxString &mimetype, int index=-1)
| Loads an image from an input stream. More...
virtual bool | SaveFile (wxOutputStream &stream, const wxString &mimetype) const
| Saves an image in the given stream. More...
virtual bool | SaveFile (const wxString &name, wxBitmapType type) const
| Saves an image in the named file. More...
virtual bool | SaveFile (const wxString &name, const wxString &mimetype) const
| Saves an image in the named file. More...
virtual bool | SaveFile (const wxString &name) const
| Saves an image in the named file. More...
virtual bool | SaveFile (wxOutputStream &stream, wxBitmapType type) const
| Saves an image in the given stream. More...
Public Member Functions inherited from wxObject
| wxObject ()
| Default ctor; initializes to NULL the internal reference data. More...
| wxObject (const wxObject &other)
| Copy ctor. More...
virtual | ~wxObject ()
| Destructor. More...
virtual wxClassInfo * | GetClassInfo () const
| This virtual function is redefined for every class that requires run-time type information, when using the wxDECLARE_CLASS macro (or similar). More...
wxObjectRefData * | GetRefData () const
| Returns the wxObject::m_refData pointer, i.e. the data referenced by this object. More...
bool | IsKindOf (const wxClassInfo *info) const
| Determines whether this class is a subclass of (or the same class as) the given class. More...
bool | IsSameAs (const wxObject &obj) const
| Returns true if this object has the same data pointer as obj. More...
void | Ref (const wxObject &clone)
| Makes this object refer to the data in clone. More...
void | SetRefData (wxObjectRefData *data)
| Sets the wxObject::m_refData pointer. More...
void | UnRef ()
| Decrements the reference count in the associated data, and if it is zero, deletes the data. More...
void | UnShare ()
| This is the same of AllocExclusive() but this method is public. More...
void | operator delete (void *buf)
| The delete operator is defined for debugging versions of the library only, when the identifier `__WXDEBUG__` is defined. More...
void * | operator new (size_t size, const wxString &filename=NULL, int lineNum=0)
| The new operator is defined for debugging versions of the library only, when the identifier `__WXDEBUG__` is defined. More...

## Static Public Member Functions
static bool | CanRead (const wxString &filename)
| Returns true if at least one of the available image handlers can read the file with the given name. More...
static bool | CanRead (wxInputStream &stream)
| Returns true if at least one of the available image handlers can read the data in the given stream. More...
static int | GetDefaultLoadFlags ()
| Returns the currently used default file load flags. More...
static wxString | GetImageExtWildcard ()
| Iterates all registered wxImageHandler objects, and returns a string containing file extension masks suitable for passing to file open/save dialog boxes. More...
static wxImage::HSVValue | RGBtoHSV (const wxImage::RGBValue &rgb)
| Converts a color in RGB color space to HSV color space. More...
static wxImage::RGBValue | HSVtoRGB (const wxImage::HSVValue &hsv)
| Converts a color in HSV color space to RGB color space. More...
Handler management functions
static void | AddHandler (wxImageHandler *handler)
| Register an image handler. More...
static void | CleanUpHandlers ()
| Deletes all image handlers. More...
static wxImageHandler * | FindHandler (const wxString &name)
| Finds the handler with the given name. More...
static wxImageHandler * | FindHandler (const wxString &extension, wxBitmapType imageType)
| Finds the handler associated with the given extension and type. More...
static wxImageHandler * | FindHandler (wxBitmapType imageType)
| Finds the handler associated with the given image type. More...
static wxImageHandler * | FindHandlerMime (const wxString &mimetype)
| Finds the handler associated with the given MIME type. More...
static wxList & | GetHandlers ()
| Returns the static list of image format handlers. More...
static void | InitStandardHandlers ()
| Internal use only. More...
static void | InsertHandler (wxImageHandler *handler)
| Adds a handler at the start of the static list of format handlers. More...
static bool | RemoveHandler (const wxString &name)
| Finds the handler with the given name, and removes it. More...
static int | GetImageCount (const wxString &filename, wxBitmapType type=wxBITMAP_TYPE_ANY)
| If the image file contains more than one image and the image handler is capable of retrieving these individually, this function will return the number of available images. More...
static int | GetImageCount (wxInputStream &stream, wxBitmapType type=wxBITMAP_TYPE_ANY)
| If the image file contains more than one image and the image handler is capable of retrieving these individually, this function will return the number of available images. More...

## Additional Inherited Members
Protected Member Functions inherited from wxObject
void | AllocExclusive ()
| Ensure that this object's data is not shared with any other object. More...
virtual wxObjectRefData * | CreateRefData () const
| Creates a new instance of the wxObjectRefData-derived class specific to this object and returns it. More...
virtual wxObjectRefData * | CloneRefData (const wxObjectRefData *data) const
| Creates a new instance of the wxObjectRefData-derived class specific to this object and initializes it copying data. More...
Protected Attributes inherited from wxObject
wxObjectRefData * | m_refData
| Pointer to an object which is the object's reference-counted data. More...

## Constructor & Destructor Documentation

## ◆ wxImage() [1/12]

wxImage::wxImage | ( |  | ) |

Creates an empty wxImage object without an alpha channel.

## ◆ wxImage() [2/12]

wxImage::wxImage | ( | int | width,
|  | int | height,
|  | bool | clear = `true`
| ) |  |

Creates an image with the given size and clears it if requested.

Does not create an alpha channel.

Parameters

  width | Specifies the width of the image.
  height | Specifies the height of the image.
  clear | If true, initialize the image to black.

## ◆ wxImage() [3/12]

wxImage::wxImage | ( | const wxSize & | sz,
|  | bool | clear = `true`
| ) |  |

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

## ◆ wxImage() [4/12]

wxImage::wxImage | ( | int | width,
|  | int | height,
|  | unsigned char * | data,
|  | bool | static_data = `false`
| ) |  |

Creates an image from data in memory.

If static_data is false then the wxImage will take ownership of the data and free it afterwards. For this, it has to be allocated with malloc.

Parameters

  width | Specifies the width of the image.
  height | Specifies the height of the image.
  data | A pointer to RGB data
  static_data | Indicates if the data should be free'd after use

## ◆ wxImage() [5/12]

wxImage::wxImage | ( | const wxSize & | sz,
|  | unsigned char * | data,
|  | bool | static_data = `false`
| ) |  |

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

## ◆ wxImage() [6/12]

wxImage::wxImage | ( | int | width,
|  | int | height,
|  | unsigned char * | data,
|  | unsigned char * | alpha,
|  | bool | static_data = `false`
| ) |  |

Creates an image from data in memory.

If static_data is false then the wxImage will take ownership of the data and free it afterwards. For this, it has to be allocated with malloc.

Parameters

  width | Specifies the width of the image.
  height | Specifies the height of the image.
  data | A pointer to RGB data
  alpha | A pointer to alpha-channel data
  static_data | Indicates if the data should be free'd after use

## ◆ wxImage() [7/12]

wxImage::wxImage | ( | const wxSize & | sz,
|  | unsigned char * | data,
|  | unsigned char * | alpha,
|  | bool | static_data = `false`
| ) |  |

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

## ◆ wxImage() [8/12]

wxImage::wxImage | ( | const char *const * | xpmData | ) |
| explicit

Creates an image from XPM data.

Parameters

  xpmData | A pointer to XPM image data.

wxPerl Note: Not supported by wxPerl.

This constructor has become `explicit` in wxWidgets 3.1.6.

## ◆ wxImage() [9/12]

wxImage::wxImage | ( | const wxString & | name,
|  | wxBitmapType | type = `wxBITMAP_TYPE_ANY`,
|  | int | index = `-1`
| ) |  |

Creates an image from a file.

Parameters

  name | Name of the file from which to load the image.
  type | May be one of the following: wxBITMAP_TYPE_BMP: Load a Windows bitmap file. wxBITMAP_TYPE_GIF: Load a GIF bitmap file. wxBITMAP_TYPE_JPEG: Load a JPEG bitmap file. wxBITMAP_TYPE_PNG: Load a PNG bitmap file. wxBITMAP_TYPE_PCX: Load a PCX bitmap file. wxBITMAP_TYPE_PNM: Load a PNM bitmap file. wxBITMAP_TYPE_TIFF: Load a TIFF bitmap file. wxBITMAP_TYPE_TGA: Load a TGA bitmap file. wxBITMAP_TYPE_XPM: Load a XPM bitmap file. wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO). wxBITMAP_TYPE_CUR: Load a Windows cursor file (CUR). wxBITMAP_TYPE_ANI: Load a Windows animated cursor file (ANI). wxBITMAP_TYPE_ANY: Will try to autodetect the format.
  index | Index of the image to load in the case that the image file contains multiple images. This is only used by GIF, ICO and TIFF handlers. The default value (-1) means "choose the default image" and is interpreted as the first image (index=0) by the GIF and TIFF handler and as the largest and most colourful one by the ICO handler.

Remarks
  Depending on how wxWidgets has been configured and by which handlers have been loaded, not all formats may be available. Any handler other than BMP must be previously initialized with wxImage::AddHandler or wxInitAllImageHandlers.

Note
  You can use GetOptionInt() to get the hotspot when loading cursor files:
  int hotspot_x = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_X);
  int hotspot_y = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_Y);
  wxIMAGE_OPTION_CUR_HOTSPOT_X
  #define wxIMAGE_OPTION_CUR_HOTSPOT_X
  Definition: image.h:107
  wxIMAGE_OPTION_CUR_HOTSPOT_Y
  #define wxIMAGE_OPTION_CUR_HOTSPOT_Y
  Definition: image.h:108

See also
  LoadFile()

## ◆ wxImage() [10/12]

wxImage::wxImage | ( | const wxString & | name,
|  | const wxString & | mimetype,
|  | int | index = `-1`
| ) |  |

Creates an image from a file using MIME-types to specify the type.

Parameters

  name | Name of the file from which to load the image.
  mimetype | MIME type string (for example 'image/jpeg')
  index | See description in wxImage(const wxString&, wxBitmapType, int) overload.

## ◆ wxImage() [11/12]

wxImage::wxImage | ( | wxInputStream & | stream,
|  | wxBitmapType | type = `wxBITMAP_TYPE_ANY`,
|  | int | index = `-1`
| ) |  |

Creates an image from a stream.

Parameters

  stream | Opened input stream from which to load the image. Currently, the stream must support seeking.
  type | See description in wxImage(const wxString&, wxBitmapType, int) overload.
  index | See description in wxImage(const wxString&, wxBitmapType, int) overload.

## ◆ wxImage() [12/12]

wxImage::wxImage | ( | wxInputStream & | stream,
|  | const wxString & | mimetype,
|  | int | index = `-1`
| ) |  |

Creates an image from a stream using MIME-types to specify the type.

Parameters

  stream | Opened input stream from which to load the image. Currently, the stream must support seeking.
  mimetype | MIME type string (for example 'image/jpeg')
  index | See description in wxImage(const wxString&, wxBitmapType, int) overload.

## ◆ ~wxImage()

virtual wxImage::~wxImage | ( |  | ) |
| virtual

Destructor.

See reference-counted object destruction for more info.

## Member Function Documentation

## ◆ AddHandler()

static void wxImage::AddHandler | ( | wxImageHandler * | handler | ) |
| static

Register an image handler.

Typical example of use:

wxImage::AddHandler(new wxPNGHandler);
wxImage::AddHandler
static void AddHandler(wxImageHandler *handler)
Register an image handler.
wxPNGHandler
This is the image handler for the PNG format.
Definition: imagpng.h:39

See Available image handlers for a list of the available handlers. You can also use wxInitAllImageHandlers() to add handlers for all the image formats supported by wxWidgets at once.

Parameters

  handler | A heap-allocated handler object which will be deleted by wxImage if it is removed later by RemoveHandler() or at program shutdown.

## ◆ Blur()

wxImage wxImage::Blur | ( | int | blurRadius | ) | const

Blurs the image in both horizontal and vertical directions by the specified pixel blurRadius.

This should not be used when using a single mask colour for transparency.

See also
  BlurHorizontal(), BlurVertical()

## ◆ BlurHorizontal()

wxImage wxImage::BlurHorizontal | ( | int | blurRadius | ) | const

Blurs the image in the horizontal direction only.

This should not be used when using a single mask colour for transparency.

See also
  Blur(), BlurVertical()

## ◆ BlurVertical()

wxImage wxImage::BlurVertical | ( | int | blurRadius | ) | const

Blurs the image in the vertical direction only.

This should not be used when using a single mask colour for transparency.

See also
  Blur(), BlurHorizontal()

## ◆ CanRead() [1/2]

static bool wxImage::CanRead | ( | const wxString & | filename | ) |
| static

Returns true if at least one of the available image handlers can read the file with the given name.

See wxImageHandler::CanRead for more info.

## ◆ CanRead() [2/2]

static bool wxImage::CanRead | ( | wxInputStream & | stream | ) |
| static

Returns true if at least one of the available image handlers can read the data in the given stream.

See wxImageHandler::CanRead for more info.

## ◆ ChangeBrightness()

void wxImage::ChangeBrightness | ( | double | factor | ) |

Changes the brightness (value) of each pixel in the image.

factor is a double in the range [-1.0..+1.0], where -1.0 corresponds to -100 percent and +1.0 corresponds to +100 percent.

Since
  3.1.6

## ◆ ChangeHSV()

void wxImage::ChangeHSV | ( | double | angleH,
|  | double | factorS,
|  | double | factorV
| ) |  |

Changes the hue, the saturation and the brightness (value) of each pixel in the image.

angleH is a double in the range [-1.0..+1.0], where -1.0 corresponds to -360 degrees and +1.0 corresponds to +360 degrees, factorS is a double in the range [-1.0..+1.0], where -1.0 corresponds to -100 percent and +1.0 corresponds to +100 percent and factorV is a double in the range [-1.0..+1.0], where -1.0 corresponds to -100 percent and +1.0 corresponds to +100 percent.

Since
  3.1.6

## ◆ ChangeLightness()

wxImage wxImage::ChangeLightness | ( | int | alpha | ) | const

Returns a changed version of the image based on the given lightness.

This utility function simply darkens or lightens a color, based on the specified percentage ialpha. ialpha of 0 would make the color completely black, 200 completely white and 100 would not change the color.

Remarks
  This function calls wxColour::ChangeLightness() for each pixel in the image.

Since
  3.1.6

## ◆ ChangeSaturation()

void wxImage::ChangeSaturation | ( | double | factor | ) |

Changes the saturation of each pixel in the image.

factor is a double in the range [-1.0..+1.0], where -1.0 corresponds to -100 percent and +1.0 corresponds to +100 percent.

Since
  3.1.6

## ◆ CleanUpHandlers()

static void wxImage::CleanUpHandlers | ( |  | ) |
| static

Deletes all image handlers.

This function is called by wxWidgets on exit.

## ◆ Clear()

void wxImage::Clear | ( | unsigned char | value = `0` | ) |

Initialize the image data with zeroes (the default) or with the byte value given as value.

Since
  2.9.0

## ◆ ClearAlpha()

void wxImage::ClearAlpha | ( |  | ) |

Removes the alpha channel from the image.

This function should only be called if the image has alpha channel data, use HasAlpha() to check for this.

Since
  2.9.1

## ◆ ComputeHistogram()

unsigned long wxImage::ComputeHistogram | ( | wxImageHistogram & | histogram | ) | const

Computes the histogram of the image.

histogram is a reference to wxImageHistogram object. wxImageHistogram is a specialization of wxHashMap "template" and is defined as follows:

class WXDLLEXPORT wxImageHistogramEntry
{
public:
wxImageHistogramEntry() : index(0), value(0) {}
unsigned long index;
unsigned long value;
};
WX_DECLARE_EXPORTED_HASH_MAP(unsigned long, wxImageHistogramEntry,
wxIntegerHash, wxIntegerEqual,
wxImageHistogram);
wxImageHistogram
Definition: image.h:2104

Returns
  Returns number of colours in the histogram.

## ◆ ConvertAlphaToMask() [1/2]

bool wxImage::ConvertAlphaToMask | ( | unsigned char | mr,
|  | unsigned char | mg,
|  | unsigned char | mb,
|  | unsigned char | threshold = `wxIMAGE_ALPHA_THRESHOLD`
| ) |  |

If the image has alpha channel, this method converts it to mask using the specified colour as the mask colour.

If the image has an alpha channel, all pixels with alpha value less than threshold are replaced with the mask colour and the alpha channel is removed. Otherwise nothing is done.

Since
  2.9.0

Parameters

  mr | The red component of the mask colour.
  mg | The green component of the mask colour.
  mb | The blue component of the mask colour.
  threshold | Pixels with alpha channel values below the given threshold are considered to be transparent, i.e. the corresponding mask pixels are set. Pixels with the alpha values above the threshold are considered to be opaque.

Returns
  Returns true on success, false on error.

## ◆ ConvertAlphaToMask() [2/2]

bool wxImage::ConvertAlphaToMask | ( | unsigned char | threshold = `wxIMAGE_ALPHA_THRESHOLD` | ) |

If the image has alpha channel, this method converts it to mask.

If the image has an alpha channel, all pixels with alpha value less than threshold are replaced with the mask colour and the alpha channel is removed. Otherwise nothing is done.

The mask colour is chosen automatically using FindFirstUnusedColour(), see the overload below if this is not appropriate.

Returns
  Returns true on success, false on error.

## ◆ ConvertToDisabled()

wxImage wxImage::ConvertToDisabled | ( | unsigned char | brightness = `255` | ) | const

Returns disabled (dimmed) version of the image.

Remarks
  This function calls wxColour::MakeDisabled() for each pixel in the image.

Since
  2.9.0

## ◆ ConvertToGreyscale() [1/2]

wxImage wxImage::ConvertToGreyscale | ( |  | ) | const

Returns a greyscale version of the image.

Since
  2.9.0

## ◆ ConvertToGreyscale() [2/2]

wxImage wxImage::ConvertToGreyscale | ( | double | weight_r,
|  | double | weight_g,
|  | double | weight_b
| ) |  | const

Returns a greyscale version of the image.

The returned image uses the luminance component of the original to calculate the greyscale. Defaults to using the standard ITU-T BT.601 when converting to YUV, where every pixel equals (R * weight_r) + (G * weight_g) + (B * weight_b).

Remarks
  This function calls wxColour::MakeGrey() for each pixel in the image.

## ◆ ConvertToMono()

wxImage wxImage::ConvertToMono | ( | unsigned char | r,
|  | unsigned char | g,
|  | unsigned char | b
| ) |  | const

Returns monochromatic version of the image.

The returned image has white colour where the original has (r,g,b) colour and black colour everywhere else.

Remarks
  This function calls wxColour::MakeMono() for each pixel in the image.

## ◆ Copy()

wxImage wxImage::Copy | ( |  | ) | const

Returns an identical copy of this image.

## ◆ Create() [1/6]

bool wxImage::Create | ( | const wxSize & | sz,
|  | bool | clear = `true`
| ) |  |

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

## ◆ Create() [2/6]

bool wxImage::Create | ( | const wxSize & | sz,
|  | unsigned char * | data,
|  | bool | static_data = `false`
| ) |  |

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

## ◆ Create() [3/6]

bool wxImage::Create | ( | const wxSize & | sz,
|  | unsigned char * | data,
|  | unsigned char * | alpha,
|  | bool | static_data = `false`
| ) |  |

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

## ◆ Create() [4/6]

bool wxImage::Create | ( | int | width,
|  | int | height,
|  | bool | clear = `true`
| ) |  |

Creates a fresh image.

See wxImage::wxImage(int,int,bool) for more info.

Returns
  true if the call succeeded, false otherwise.

## ◆ Create() [5/6]

bool wxImage::Create | ( | int | width,
|  | int | height,
|  | unsigned char * | data,
|  | bool | static_data = `false`
| ) |  |

Creates a fresh image.

See wxImage::wxImage(int,int,unsigned char*,bool) for more info.

Returns
  true if the call succeeded, false otherwise.

## ◆ Create() [6/6]

bool wxImage::Create | ( | int | width,
|  | int | height,
|  | unsigned char * | data,
|  | unsigned char * | alpha,
|  | bool | static_data = `false`
| ) |  |

Creates a fresh image.

See wxImage::wxImage(int,int,unsigned char*,unsigned char*,bool) for more info.

Returns
  true if the call succeeded, false otherwise.

## ◆ Destroy()

void wxImage::Destroy | ( |  | ) |

Destroys the image data.

## ◆ FindFirstUnusedColour()

bool wxImage::FindFirstUnusedColour | ( | unsigned char * | r,
|  | unsigned char * | g,
|  | unsigned char * | b,
|  | unsigned char | startR = `1`,
|  | unsigned char | startG = `0`,
|  | unsigned char | startB = `0`
| ) |  | const

Finds the first colour that is never used in the image.

The search begins at given initial colour and continues by increasing R, G and B components (in this order) by 1 until an unused colour is found or the colour space exhausted.

The parameters r, g, b are pointers to variables to save the colour.

The parameters startR, startG, startB define the initial values of the colour. The returned colour will have RGB values equal to or greater than these.

Returns
  Returns false if there is no unused colour left, true on success.

Note
  This method involves computing the histogram, which is a computationally intensive operation.

## ◆ FindHandler() [1/3]

static wxImageHandler* wxImage::FindHandler | ( | const wxString & | extension,
|  | wxBitmapType | imageType
| ) |  |
| static

Finds the handler associated with the given extension and type.

Parameters

  extension | The file extension, such as "bmp".
  imageType | The image type; one of the wxBitmapType values.

Returns
  A pointer to the handler if found, NULL otherwise.

See also
  wxImageHandler

## ◆ FindHandler() [2/3]

static wxImageHandler* wxImage::FindHandler | ( | const wxString & | name | ) |
| static

Finds the handler with the given name.

Parameters

  name | The handler name.

Returns
  A pointer to the handler if found, NULL otherwise.

See also
  wxImageHandler

## ◆ FindHandler() [3/3]

static wxImageHandler* wxImage::FindHandler | ( | wxBitmapType | imageType | ) |
| static

Finds the handler associated with the given image type.

Parameters

  imageType | The image type; one of the wxBitmapType values.

Returns
  A pointer to the handler if found, NULL otherwise.

See also
  wxImageHandler

## ◆ FindHandlerMime()

static wxImageHandler* wxImage::FindHandlerMime | ( | const wxString & | mimetype | ) |
| static

Finds the handler associated with the given MIME type.

Parameters

  mimetype | MIME type.

Returns
  A pointer to the handler if found, NULL otherwise.

See also
  wxImageHandler

## ◆ GetAlpha() [1/2]

unsigned char* wxImage::GetAlpha | ( |  | ) | const

Returns pointer to the array storing the alpha values for this image.

This pointer is NULL for the images without the alpha channel. If the image does have it, this pointer may be used to directly manipulate the alpha values which are stored as the RGB ones.

## ◆ GetAlpha() [2/2]

unsigned char wxImage::GetAlpha | ( | int | x,
|  | int | y
| ) |  | const

Return alpha value at given pixel location.

## ◆ GetBlue()

unsigned char wxImage::GetBlue | ( | int | x,
|  | int | y
| ) |  | const

Returns the blue intensity at the given coordinate.

## ◆ GetData()

unsigned char* wxImage::GetData | ( |  | ) | const

Returns the image data as an array.

This is most often used when doing direct image manipulation. The return value points to an array of characters in RGBRGBRGB... format in the top-to-bottom, left-to-right order, that is the first RGB triplet corresponds to the first pixel of the first row, the second one — to the second pixel of the first row and so on until the end of the first row, with second row following after it and so on.

You should not delete the returned pointer nor pass it to SetData().

## ◆ GetDefaultLoadFlags()

static int wxImage::GetDefaultLoadFlags | ( |  | ) |
| static

Returns the currently used default file load flags.

See SetDefaultLoadFlags() for more information about these flags.

Since
  3.1.0

## ◆ GetGreen()

unsigned char wxImage::GetGreen | ( | int | x,
|  | int | y
| ) |  | const

Returns the green intensity at the given coordinate.

## ◆ GetHandlers()

static wxList& wxImage::GetHandlers | ( |  | ) |
| static

Returns the static list of image format handlers.

See also
  wxImageHandler

## ◆ GetHeight()

int wxImage::GetHeight | ( |  | ) | const

Gets the height of the image in pixels.

See also
  GetWidth(), GetSize()

## ◆ GetImageCount() [1/2]

static int wxImage::GetImageCount | ( | const wxString & | filename,
|  | wxBitmapType | type = `wxBITMAP_TYPE_ANY`
| ) |  |
| static

If the image file contains more than one image and the image handler is capable of retrieving these individually, this function will return the number of available images.

For the overload taking the parameter filename, that's the name of the file to query. For the overload taking the parameter stream, that's the opened input stream with image data.

See wxImageHandler::GetImageCount() for more info.

The parameter type may be one of the following values:

- wxBITMAP_TYPE_BMP: Load a Windows bitmap file.
- wxBITMAP_TYPE_GIF: Load a GIF bitmap file.
- wxBITMAP_TYPE_JPEG: Load a JPEG bitmap file.
- wxBITMAP_TYPE_PNG: Load a PNG bitmap file.
- wxBITMAP_TYPE_PCX: Load a PCX bitmap file.
- wxBITMAP_TYPE_PNM: Load a PNM bitmap file.
- wxBITMAP_TYPE_TIFF: Load a TIFF bitmap file.
- wxBITMAP_TYPE_TGA: Load a TGA bitmap file.
- wxBITMAP_TYPE_XPM: Load a XPM bitmap file.
- wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO).
- wxBITMAP_TYPE_CUR: Load a Windows cursor file (CUR).
- wxBITMAP_TYPE_ANI: Load a Windows animated cursor file (ANI).
- wxBITMAP_TYPE_ANY: Will try to autodetect the format.

Returns
  Number of available images. For most image handlers, this is 1 (exceptions are TIFF and ICO formats as well as animated GIFs for which this function returns the number of frames in the animation).

## ◆ GetImageCount() [2/2]

static int wxImage::GetImageCount | ( | wxInputStream & | stream,
|  | wxBitmapType | type = `wxBITMAP_TYPE_ANY`
| ) |  |
| static

If the image file contains more than one image and the image handler is capable of retrieving these individually, this function will return the number of available images.

For the overload taking the parameter filename, that's the name of the file to query. For the overload taking the parameter stream, that's the opened input stream with image data.

See wxImageHandler::GetImageCount() for more info.

The parameter type may be one of the following values:

- wxBITMAP_TYPE_BMP: Load a Windows bitmap file.
- wxBITMAP_TYPE_GIF: Load a GIF bitmap file.
- wxBITMAP_TYPE_JPEG: Load a JPEG bitmap file.
- wxBITMAP_TYPE_PNG: Load a PNG bitmap file.
- wxBITMAP_TYPE_PCX: Load a PCX bitmap file.
- wxBITMAP_TYPE_PNM: Load a PNM bitmap file.
- wxBITMAP_TYPE_TIFF: Load a TIFF bitmap file.
- wxBITMAP_TYPE_TGA: Load a TGA bitmap file.
- wxBITMAP_TYPE_XPM: Load a XPM bitmap file.
- wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO).
- wxBITMAP_TYPE_CUR: Load a Windows cursor file (CUR).
- wxBITMAP_TYPE_ANI: Load a Windows animated cursor file (ANI).
- wxBITMAP_TYPE_ANY: Will try to autodetect the format.

Returns
  Number of available images. For most image handlers, this is 1 (exceptions are TIFF and ICO formats as well as animated GIFs for which this function returns the number of frames in the animation).

## ◆ GetImageExtWildcard()

static wxString wxImage::GetImageExtWildcard | ( |  | ) |
| static

Iterates all registered wxImageHandler objects, and returns a string containing file extension masks suitable for passing to file open/save dialog boxes.

Returns
  The format of the returned string is `"(*.ext1;*.ext2)|*.ext1;*.ext2"`. It is usually a good idea to prepend a description before passing the result to the dialog. Example:
  wxFileDialog FileDlg( this, "Choose Image", ::wxGetCwd(), "",
  _("Image Files ") + wxImage::GetImageExtWildcard(),
  wxFD_OPEN );
  wxFileDialog
  This class represents the file chooser dialog.
  Definition: filedlg.h:194
  wxImage::GetImageExtWildcard
  static wxString GetImageExtWildcard()
  Iterates all registered wxImageHandler objects, and returns a string containing file extension masks ...
  wxFD_OPEN
  @ wxFD_OPEN
  Definition: filedlg.h:10
  wxGetCwd
  wxString wxGetCwd()
  Returns a string containing the current (or working) directory.
  _
  const wxString & _(const wxString &string)
  Macro to be used around all literal strings that should be translated.

See also
  wxImageHandler

## ◆ GetLoadFlags()

int wxImage::GetLoadFlags | ( |  | ) | const

Returns the file load flags used for this object.

See SetLoadFlags() for more information about these flags.

Since
  3.1.0

## ◆ GetMaskBlue()

unsigned char wxImage::GetMaskBlue | ( |  | ) | const

Gets the blue value of the mask colour.

## ◆ GetMaskGreen()

unsigned char wxImage::GetMaskGreen | ( |  | ) | const

Gets the green value of the mask colour.

## ◆ GetMaskRed()

unsigned char wxImage::GetMaskRed | ( |  | ) | const

Gets the red value of the mask colour.

## ◆ GetOption()

wxString wxImage::GetOption | ( | const wxString & | name | ) | const

Gets a user-defined string-valued option.

Generic options:

- `wxIMAGE_OPTION_FILENAME:` The name of the file from which the image was loaded.

Options specific to wxGIFHandler:

- `wxIMAGE_OPTION_GIF_COMMENT:` The comment text that is read from or written to the GIF file. In an animated GIF each frame can have its own comment. If there is only a comment in the first frame of a GIF it will not be repeated in other frames.

Parameters

  name | The name of the option, case-insensitive.

Returns
  The value of the option or an empty string if not found. Use HasOption() if an empty string can be a valid option value.

See also
  SetOption(), GetOptionInt(), HasOption()

## ◆ GetOptionInt()

int wxImage::GetOptionInt | ( | const wxString & | name | ) | const

Gets a user-defined integer-valued option.

The function is case-insensitive to name. If the given option is not present, the function returns 0. Use HasOption() if 0 is a possibly valid value for the option.

Generic options:

- `wxIMAGE_OPTION_MAX_WIDTH` and `wxIMAGE_OPTION_MAX_HEIGHT:` If either of these options is specified, the loaded image will be scaled down (preserving its aspect ratio) so that its width is less than the max width given if it is not 0 and its height is less than the max height given if it is not 0. This is typically used for loading thumbnails and the advantage of using these options compared to calling Rescale() after loading is that some handlers (only JPEG one right now) support rescaling the image during loading which is vastly more efficient than loading the entire huge image and rescaling it later (if these options are not supported by the handler, this is still what happens however). These options must be set before calling LoadFile() to have any effect.

- `wxIMAGE_OPTION_ORIGINAL_WIDTH` and `wxIMAGE_OPTION_ORIGINAL_HEIGHT:` These options will return the original size of the image if either `wxIMAGE_OPTION_MAX_WIDTH` or `wxIMAGE_OPTION_MAX_HEIGHT` is specified.
  Since
    2.9.3
- `wxIMAGE_OPTION_QUALITY:` JPEG quality used when saving. This is an integer in 0..100 range with 0 meaning very poor and 100 excellent (but very badly compressed). This option is currently ignored for the other formats.

- `wxIMAGE_OPTION_RESOLUTIONUNIT:` The value of this option determines whether the resolution of the image is specified in centimetres or inches, see wxImageResolution enum elements.

- `wxIMAGE_OPTION_RESOLUTION`, `wxIMAGE_OPTION_RESOLUTIONX` and `wxIMAGE_OPTION_RESOLUTIONY:` These options define the resolution of the image in the units corresponding to `wxIMAGE_OPTION_RESOLUTIONUNIT` options value. The first option can be set before saving the image to set both horizontal and vertical resolution to the same value. The X and Y options are set by the image handlers if they support the image resolution (currently BMP, JPEG and TIFF handlers do) and the image provides the resolution information and can be queried after loading the image.

Options specific to wxPNGHandler:

- `wxIMAGE_OPTION_PNG_FORMAT:` Format for saving a PNG file, see wxImagePNGType for the supported values.
- `wxIMAGE_OPTION_PNG_BITDEPTH:` Bit depth for every channel (R/G/B/A).
- `wxIMAGE_OPTION_PNG_FILTER:` Filter for saving a PNG file, see libpng (http://www.libpng.org/pub/png/libpng-1.2.5-manual.html) for possible values (e.g. PNG_FILTER_NONE, PNG_FILTER_SUB, PNG_FILTER_UP, etc).
- `wxIMAGE_OPTION_PNG_COMPRESSION_LEVEL:` Compression level (0..9) for saving a PNG file. A high value creates smaller-but-slower PNG file. Note that unlike other formats (e.g. JPEG) the PNG format is always lossless and thus this compression level doesn't tradeoff the image quality.
- `wxIMAGE_OPTION_PNG_COMPRESSION_MEM_LEVEL:` Compression memory usage level (1..9) for saving a PNG file. A high value means the saving process consumes more memory, but may create smaller PNG file.
- `wxIMAGE_OPTION_PNG_COMPRESSION_STRATEGY:` Possible values are 0 for default strategy, 1 for filter, and 2 for Huffman-only. You can use OptiPNG (http://optipng.sourceforge.net/) to get a suitable value for your application.
- `wxIMAGE_OPTION_PNG_COMPRESSION_BUFFER_SIZE:` Internal buffer size (in bytes) for saving a PNG file. Ideally this should be as big as the resulting PNG file. Use this option if your application produces images with small size variation.

Options specific to wxTIFFHandler:

- `wxIMAGE_OPTION_TIFF_BITSPERSAMPLE:` Number of bits per sample (channel). Currently values of 1 and 8 are supported. A value of 1 results in a black and white image. A value of 8 (the default) can mean greyscale or RGB, depending on the value of `wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL`.
- `wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL:` Number of samples (channels) per pixel. Currently values of 1 and 3 are supported. A value of 1 results in either a greyscale (by default) or black and white image, depending on the value of `wxIMAGE_OPTION_TIFF_BITSPERSAMPLE`. A value of 3 (the default) will result in an RGB image.
- `wxIMAGE_OPTION_TIFF_COMPRESSION:` Compression type. By default it is set to 1 (COMPRESSION_NONE). Typical other values are 5 (COMPRESSION_LZW) and 7 (COMPRESSION_JPEG). See tiff.h for more options.
- `wxIMAGE_OPTION_TIFF_PHOTOMETRIC:` Specifies the photometric interpretation. By default it is set to 2 (PHOTOMETRIC_RGB) for RGB images and 0 (PHOTOMETRIC_MINISWHITE) for greyscale or black and white images. It can also be set to 1 (PHOTOMETRIC_MINISBLACK) to treat the lowest value as black and highest as white. If you want a greyscale image it is also sufficient to only specify `wxIMAGE_OPTION_TIFF_PHOTOMETRIC` and set it to either PHOTOMETRIC_MINISWHITE or PHOTOMETRIC_MINISBLACK. The other values are taken care of.

Options specific to wxGIFHandler:

- `wxIMAGE_OPTION_GIF_TRANSPARENCY:` How to deal with transparent pixels. By default, the color of transparent pixels is changed to bright pink, so that if the image is accidentally drawn without transparency, it will be obvious. Normally, this would not be noticed, as these pixels will not be rendered. But in some cases it might be useful to load a GIF without making any modifications to its colours. Use `wxIMAGE_OPTION_GIF_TRANSPARENCY_UNCHANGED` to keep the colors correct. Use `wxIMAGE_OPTION_GIF_TRANSPARENCY_HIGHLIGHT` to convert transparent pixels to pink (default). This option has been added in wxWidgets 3.1.1.

Note
  Be careful when combining the options `wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL`, `wxIMAGE_OPTION_TIFF_BITSPERSAMPLE`, and `wxIMAGE_OPTION_TIFF_PHOTOMETRIC`. While some measures are taken to prevent illegal combinations and/or values, it is still easy to abuse them and come up with invalid results in the form of either corrupted images or crashes.

Parameters

  name | The name of the option, case-insensitive.

Returns
  The value of the option or 0 if not found. Use HasOption() if 0 can be a valid option value.

See also
  SetOption(), GetOption()

## ◆ GetOrFindMaskColour()

bool wxImage::GetOrFindMaskColour | ( | unsigned char * | r,
|  | unsigned char * | g,
|  | unsigned char * | b
| ) |  | const

Get the current mask colour or find a suitable unused colour that could be used as a mask colour.

Returns true if the image currently has a mask.

## ◆ GetPalette()

const wxPalette& wxImage::GetPalette | ( |  | ) | const

Returns the palette associated with the image.

Currently the palette is only used when converting to wxBitmap under Windows.

Some of the wxImage handlers have been modified to set the palette if one exists in the image file (usually 256 or less colour images in GIF or PNG format).

## ◆ GetRed()

unsigned char wxImage::GetRed | ( | int | x,
|  | int | y
| ) |  | const

Returns the red intensity at the given coordinate.

## ◆ GetSize()

wxSize wxImage::GetSize | ( |  | ) | const

Returns the size of the image in pixels.

Since
  2.9.0

See also
  GetHeight(), GetWidth()

## ◆ GetSubImage()

wxImage wxImage::GetSubImage | ( | const wxRect & | rect | ) | const

Returns a sub image of the current one as long as the rect belongs entirely to the image.

## ◆ GetType()

wxBitmapType wxImage::GetType | ( |  | ) | const

Gets the type of image found by LoadFile() or specified with SaveFile().

Since
  2.9.0

## ◆ GetWidth()

int wxImage::GetWidth | ( |  | ) | const

Gets the width of the image in pixels.

See also
  GetHeight(), GetSize()

## ◆ HasAlpha()

bool wxImage::HasAlpha | ( |  | ) | const

Returns true if this image has alpha channel, false otherwise.

See also
  GetAlpha(), SetAlpha()

## ◆ HasMask()

bool wxImage::HasMask | ( |  | ) | const

Returns true if there is a mask active, false otherwise.

## ◆ HasOption()

bool wxImage::HasOption | ( | const wxString & | name | ) | const

Returns true if the given option is present.

The function is case-insensitive to name.

The lists of the currently supported options are in GetOption() and GetOptionInt() function docs.

See also
  SetOption(), GetOption(), GetOptionInt()

## ◆ HSVtoRGB()

static wxImage::RGBValue wxImage::HSVtoRGB | ( | const wxImage::HSVValue & | hsv | ) |
| static

Converts a color in HSV color space to RGB color space.

## ◆ InitAlpha()

void wxImage::InitAlpha | ( |  | ) |

Initializes the image alpha channel data.

It is an error to call it if the image already has alpha data. If it doesn't, alpha data will be by default initialized to all pixels being fully opaque. But if the image has a mask colour, all mask pixels will be completely transparent.

## ◆ InitStandardHandlers()

static void wxImage::InitStandardHandlers | ( |  | ) |
| static

Internal use only.

Adds standard image format handlers. It only install wxBMPHandler for the time being, which is used by wxBitmap.

This function is called by wxWidgets on startup, and shouldn't be called by the user.

See also
  wxImageHandler, wxInitAllImageHandlers(), wxQuantize

## ◆ InsertHandler()

static void wxImage::InsertHandler | ( | wxImageHandler * | handler | ) |
| static

Adds a handler at the start of the static list of format handlers.

Parameters

  handler | A new image format handler object. There is usually only one instance of a given handler class in an application session.

See also
  wxImageHandler

## ◆ IsOk()

bool wxImage::IsOk | ( |  | ) | const

Returns true if image data is present.

## ◆ IsTransparent()

bool wxImage::IsTransparent | ( | int | x,
|  | int | y,
|  | unsigned char | threshold = `wxIMAGE_ALPHA_THRESHOLD`
| ) |  | const

Returns true if the given pixel is transparent, i.e. either has the mask colour if this image has a mask or if this image has alpha channel and alpha value of this pixel is strictly less than threshold.

## ◆ LoadFile() [1/4]

virtual bool wxImage::LoadFile | ( | const wxString & | name,
|  | const wxString & | mimetype,
|  | int | index = `-1`
| ) |  |
| virtual

Loads an image from a file.

If no handler type is provided, the library will try to autodetect the format.

Parameters

  name | Name of the file from which to load the image.
  mimetype | MIME type string (for example 'image/jpeg')
  index | See the description in the LoadFile(wxInputStream&, wxBitmapType, int) overload.

## ◆ LoadFile() [2/4]

virtual bool wxImage::LoadFile | ( | const wxString & | name,
|  | wxBitmapType | type = `wxBITMAP_TYPE_ANY`,
|  | int | index = `-1`
| ) |  |
| virtual

Loads an image from a file.

If no handler type is provided, the library will try to autodetect the format.

Parameters

  name | Name of the file from which to load the image.
  type | See the description in the LoadFile(wxInputStream&, wxBitmapType, int) overload.
  index | See the description in the LoadFile(wxInputStream&, wxBitmapType, int) overload.

## ◆ LoadFile() [3/4]

virtual bool wxImage::LoadFile | ( | wxInputStream & | stream,
|  | const wxString & | mimetype,
|  | int | index = `-1`
| ) |  |
| virtual

Loads an image from an input stream.

Parameters

  stream | Opened input stream from which to load the image. Currently, the stream must support seeking.
  mimetype | MIME type string (for example 'image/jpeg')
  index | See the description in the LoadFile(wxInputStream&, wxBitmapType, int) overload.

## ◆ LoadFile() [4/4]

virtual bool wxImage::LoadFile | ( | wxInputStream & | stream,
|  | wxBitmapType | type = `wxBITMAP_TYPE_ANY`,
|  | int | index = `-1`
| ) |  |
| virtual

Loads an image from an input stream.

If the file can't be loaded, this function returns false and logs an error using wxLogError(). If the file can be loaded but some problems were detected while doing it, it can also call wxLogWarning() to notify about these problems. If this is undesirable, use SetLoadFlags() to reset `Load_Verbose` flag and suppress these warnings.

Parameters

  stream | Opened input stream from which to load the image. Currently, the stream must support seeking.
  type | May be one of the following: wxBITMAP_TYPE_BMP: Load a Windows bitmap file. wxBITMAP_TYPE_GIF: Load a GIF bitmap file. wxBITMAP_TYPE_JPEG: Load a JPEG bitmap file. wxBITMAP_TYPE_PNG: Load a PNG bitmap file. wxBITMAP_TYPE_PCX: Load a PCX bitmap file. wxBITMAP_TYPE_PNM: Load a PNM bitmap file. wxBITMAP_TYPE_TIFF: Load a TIFF bitmap file. wxBITMAP_TYPE_TGA: Load a TGA bitmap file. wxBITMAP_TYPE_XPM: Load a XPM bitmap file. wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO). wxBITMAP_TYPE_CUR: Load a Windows cursor file (CUR). wxBITMAP_TYPE_ANI: Load a Windows animated cursor file (ANI). wxBITMAP_TYPE_ANY: Will try to autodetect the format.
  index | Index of the image to load in the case that the image file contains multiple images. This is only used by GIF, ICO and TIFF handlers. The default value (-1) means "choose the default image" and is interpreted as the first image (index=0) by the GIF and TIFF handler and as the largest and most colourful one by the ICO handler.

Returns
  true if the operation succeeded, false otherwise. If the optional index parameter is out of range, false is returned and a call to wxLogError() takes place.

Remarks
  Depending on how wxWidgets has been configured, not all formats may be available.

Note
  You can use GetOptionInt() to get the hotspot when loading cursor files:
  int hotspot_x = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_X);
  int hotspot_y = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_Y);

See also
  SaveFile()

## ◆ Mirror()

wxImage wxImage::Mirror | ( | bool | horizontally = `true` | ) | const

Returns a mirrored copy of the image.

The parameter horizontally indicates the orientation.

## ◆ operator=()

wxImage& wxImage::operator= | ( | const wxImage & | image | ) |

Assignment operator, using reference counting.

Parameters

  image | Image to assign.

Returns
  Returns 'this' object.

## ◆ Paste()

void wxImage::Paste | ( | const wxImage & | image,
|  | int | x,
|  | int | y,
|  | wxImageAlphaBlendMode | alphaBlend = `wxIMAGE_ALPHA_BLEND_OVER`
| ) |  |

Copy the data of the given image to the specified position in this image.

Takes care of the mask colour and out of bounds problems.

Parameters

  image | The image containing the data to copy, must be valid.
  x | The horizontal position of the position to copy the data to.
  y | The vertical position of the position to copy the data to.
  alphaBlend | This parameter (new in wx 3.1.5) determines whether the alpha values of the original image replace (default) or are composed with the alpha channel of this image. Notice that alpha blending overrides the mask handling.

## ◆ RemoveHandler()

static bool wxImage::RemoveHandler | ( | const wxString & | name | ) |
| static

Finds the handler with the given name, and removes it.

The handler is also deleted.

Parameters

  name | The handler name.

Returns
  true if the handler was found and removed, false otherwise.

See also
  wxImageHandler

## ◆ Replace()

void wxImage::Replace | ( | unsigned char | r1,
|  | unsigned char | g1,
|  | unsigned char | b1,
|  | unsigned char | r2,
|  | unsigned char | g2,
|  | unsigned char | b2
| ) |  |

Replaces the colour specified by r1,g1,b1 by the colour r2,g2,b2.

## ◆ Rescale()

wxImage& wxImage::Rescale | ( | int | width,
|  | int | height,
|  | wxImageResizeQuality | quality = `wxIMAGE_QUALITY_NORMAL`
| ) |  |

Changes the size of the image in-place by scaling it: after a call to this function,the image will have the given width and height.

For a description of the quality parameter, see the Scale() function. Returns the (modified) image itself.

See also
  Scale()

## ◆ Resize()

wxImage& wxImage::Resize | ( | const wxSize & | size,
|  | const wxPoint & | pos,
|  | int | red = `-1`,
|  | int | green = `-1`,
|  | int | blue = `-1`
| ) |  |

Changes the size of the image in-place without scaling it by adding either a border with the given colour or cropping as necessary.

The image is pasted into a new image with the given size and background colour at the position pos relative to the upper left of the new image.

If red = green = blue = -1 then use either the current mask colour if set or find, use, and set a suitable mask colour for any newly exposed areas.

Returns
  The (modified) image itself.

See also
  Size()

## ◆ RGBtoHSV()

static wxImage::HSVValue wxImage::RGBtoHSV | ( | const wxImage::RGBValue & | rgb | ) |
| static

Converts a color in RGB color space to HSV color space.

## ◆ Rotate()

wxImage wxImage::Rotate | ( | double | angle,
|  | const wxPoint & | rotationCentre,
|  | bool | interpolating = `true`,
|  | wxPoint * | offsetAfterRotation = `NULL`
| ) |  | const

Rotates the image about the given point, by angle radians.

Passing true to interpolating results in better image quality, but is slower.

If the image has a mask, then the mask colour is used for the uncovered pixels in the rotated image background. Else, black (rgb 0, 0, 0) will be used.

Returns the rotated image, leaving this image intact.

## ◆ Rotate180()

wxImage wxImage::Rotate180 | ( |  | ) | const

Returns a copy of the image rotated by 180 degrees.

Since
  2.9.2

## ◆ Rotate90()

wxImage wxImage::Rotate90 | ( | bool | clockwise = `true` | ) | const

Returns a copy of the image rotated 90 degrees in the direction indicated by clockwise.

## ◆ RotateHue()

void wxImage::RotateHue | ( | double | angle | ) |

Rotates the hue of each pixel in the image by angle, which is a double in the range [-1.0..+1.0], where -1.0 corresponds to -360 degrees and +1.0 corresponds to +360 degrees.

## ◆ SaveFile() [1/5]

virtual bool wxImage::SaveFile | ( | const wxString & | name | ) | const
| virtual

Saves an image in the named file.

File type is determined from the extension of the file name. Note that this function may fail if the extension is not recognized! You can use one of the forms above to save images to files with non-standard extensions.

Parameters

  name | Name of the file to save the image to.

## ◆ SaveFile() [2/5]

virtual bool wxImage::SaveFile | ( | const wxString & | name,
|  | const wxString & | mimetype
| ) |  | const
| virtual

Saves an image in the named file.

Parameters

  name | Name of the file to save the image to.
  mimetype | MIME type.

## ◆ SaveFile() [3/5]

virtual bool wxImage::SaveFile | ( | const wxString & | name,
|  | wxBitmapType | type
| ) |  | const
| virtual

Saves an image in the named file.

Parameters

  name | Name of the file to save the image to.
  type | Currently these types can be used: wxBITMAP_TYPE_BMP: Save a BMP image file. wxBITMAP_TYPE_JPEG: Save a JPEG image file. wxBITMAP_TYPE_PNG: Save a PNG image file. wxBITMAP_TYPE_PCX: Save a PCX image file (tries to save as 8-bit if possible, falls back to 24-bit otherwise). wxBITMAP_TYPE_PNM: Save a PNM image file (as raw RGB always). wxBITMAP_TYPE_TIFF: Save a TIFF image file. wxBITMAP_TYPE_XPM: Save a XPM image file. wxBITMAP_TYPE_ICO: Save a Windows icon file (ICO). The size may be up to 255 wide by 127 high. A single image is saved in 8 colors at the size supplied. wxBITMAP_TYPE_CUR: Save a Windows cursor file (CUR).

## ◆ SaveFile() [4/5]

virtual bool wxImage::SaveFile | ( | wxOutputStream & | stream,
|  | const wxString & | mimetype
| ) |  | const
| virtual

Saves an image in the given stream.

Parameters

  stream | Opened output stream to save the image to.
  mimetype | MIME type.

Returns
  true if the operation succeeded, false otherwise.

Remarks
  Depending on how wxWidgets has been configured, not all formats may be available.

Note
  You can use SetOption() to set the hotspot when saving an image into a cursor file (default hotspot is in the centre of the image):
  image.SetOption(wxIMAGE_OPTION_CUR_HOTSPOT_X, hotspotX);
  image.SetOption(wxIMAGE_OPTION_CUR_HOTSPOT_Y, hotspotY);

See also
  LoadFile()

## ◆ SaveFile() [5/5]

virtual bool wxImage::SaveFile | ( | wxOutputStream & | stream,
|  | wxBitmapType | type
| ) |  | const
| virtual

Saves an image in the given stream.

Parameters

  stream | Opened output stream to save the image to.
  type | MIME type.

## ◆ Scale()

wxImage wxImage::Scale | ( | int | width,
|  | int | height,
|  | wxImageResizeQuality | quality = `wxIMAGE_QUALITY_NORMAL`
| ) |  | const

Returns a scaled version of the image.

This is also useful for scaling bitmaps in general as the only other way to scale bitmaps is to blit a wxMemoryDC into another wxMemoryDC.

The parameter quality determines what method to use for resampling the image, see wxImageResizeQuality documentation.

It should be noted that although using `wxIMAGE_QUALITY_HIGH` produces much nicer looking results it is a slower method. Downsampling will use the box averaging method which seems to operate very fast. If you are upsampling larger images using this method you will most likely notice that it is a bit slower and in extreme cases it will be quite substantially slower as the bicubic algorithm has to process a lot of data.

It should also be noted that the high quality scaling may not work as expected when using a single mask colour for transparency, as the scaling will blur the image and will therefore remove the mask partially. Using the alpha channel will work.

Example:

// get the bitmap from somewhere
wxBitmap bmp = ...;
// rescale it to have size of 32*32
if ( bmp.GetWidth() != 32 || bmp.GetHeight() != 32 )
{
wxImage image = bmp.ConvertToImage();
bmp = wxBitmap(image.Scale(32, 32));
// another possibility:
image.Rescale(32, 32);
bmp = image;
}
wxBitmap
This class encapsulates the concept of a platform-dependent bitmap, either monochrome or colour or co...
Definition: bitmap.h:212
wxBitmap::GetWidth
virtual int GetWidth() const
Returns the width of the bitmap in physical pixels.
wxBitmap::GetHeight
virtual int GetHeight() const
Returns the height of the bitmap in physical pixels.
wxBitmap::ConvertToImage
virtual wxImage ConvertToImage() const
Creates an image from a platform-dependent bitmap.
wxImage
This class encapsulates a platform-independent image.
Definition: image.h:490
wxImage::Rescale
wxImage & Rescale(int width, int height, wxImageResizeQuality quality=wxIMAGE_QUALITY_NORMAL)
Changes the size of the image in-place by scaling it: after a call to this function,...
wxImage::Scale
wxImage Scale(int width, int height, wxImageResizeQuality quality=wxIMAGE_QUALITY_NORMAL) const
Returns a scaled version of the image.

Note
  The algorithm used for the default (normal) quality value doesn't work with images larger than 65536 (2^16) pixels in either dimension for 32-bit programs. For 64-bit programs the limit is 2^48 and so not relevant in practice.

See also
  Rescale()

## ◆ SetAlpha() [1/2]

void wxImage::SetAlpha | ( | int | x,
|  | int | y,
|  | unsigned char | alpha
| ) |  |

Sets the alpha value for the given pixel.

This function should only be called if the image has alpha channel data, use HasAlpha() to check for this.

## ◆ SetAlpha() [2/2]

void wxImage::SetAlpha | ( | unsigned char * | alpha = `NULL`,
|  | bool | static_data = `false`
| ) |  |

This function is similar to SetData() and has similar restrictions.

The pointer passed to it may however be NULL in which case the function will allocate the alpha array internally – this is useful to add alpha channel data to an image which doesn't have any.

If the pointer is not NULL, it must have one byte for each image pixel and be allocated with malloc(). wxImage takes ownership of the pointer and will free it unless static_data parameter is set to true – in this case the caller should do it.

## ◆ SetData() [1/2]

void wxImage::SetData | ( | unsigned char * | data,
|  | bool | static_data = `false`
| ) |  |

Sets the image data without performing checks.

The data given must have the size (width*height*3) or results will be unexpected. Don't use this method if you aren't sure you know what you are doing.

The data must have been allocated with `malloc()`, NOT with `operator` new.

If static_data is false, after this call the pointer to the data is owned by the wxImage object, that will be responsible for deleting it. Do not pass to this function a pointer obtained through GetData().

## ◆ SetData() [2/2]

void wxImage::SetData | ( | unsigned char * | data,
|  | int | new_width,
|  | int | new_height,
|  | bool | static_data = `false`
| ) |  |

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

## ◆ SetDefaultLoadFlags()

static void wxImage::SetDefaultLoadFlags | ( | int | flags | ) |
| static

Sets the default value for the flags used for loading image files.

This method changes the global value of the flags used for all the subsequently created wxImage objects by default. It doesn't affect the already existing objects.

By default, the global flags include `Load_Verbose` flag value.

See also
  LoadFile(), SetLoadFlags(), GetDefaultLoadFlags()

Since
  3.1.0

## ◆ SetLoadFlags()

void wxImage::SetLoadFlags | ( | int | flags | ) |

Sets the flags used for loading image files by this object.

The flags will affect any future calls to LoadFile() for this object. To change the flags for all image objects, call SetDefaultLoadFlags() before creating any of them.

Currently the only defined flag is `Load_Verbose` which determines if the non-fatal (i.e. not preventing the file from being loaded completely) problems should result in the calls to wxLogWarning() function. It is recommended to customize handling of these warnings by e.g. defining a custom log target (see Logging Overview), but if such warnings should be completely suppressed, clearing this flag provides a simple way to do it, for example:

wxImage image;
image.SetLoadFlags(image.GetLoadFlags() & ~wxImage::Load_Verbose);
image.LoadFile(...);
wxImage::GetLoadFlags
int GetLoadFlags() const
Returns the file load flags used for this object.
wxImage::LoadFile
virtual bool LoadFile(wxInputStream &stream, wxBitmapType type=wxBITMAP_TYPE_ANY, int index=-1)
Loads an image from an input stream.
wxImage::SetLoadFlags
void SetLoadFlags(int flags)
Sets the flags used for loading image files by this object.

See also
  LoadFile(), SetLoadFlags(), GetLoadFlags()

Since
  3.1.0

## ◆ SetMask()

void wxImage::SetMask | ( | bool | hasMask = `true` | ) |

Specifies whether there is a mask or not.

The area of the mask is determined by the current mask colour.

## ◆ SetMaskColour()

void wxImage::SetMaskColour | ( | unsigned char | red,
|  | unsigned char | green,
|  | unsigned char | blue
| ) |  |

Sets the mask colour for this image (and tells the image to use the mask).

## ◆ SetMaskFromImage()

bool wxImage::SetMaskFromImage | ( | const wxImage & | mask,
|  | unsigned char | mr,
|  | unsigned char | mg,
|  | unsigned char | mb
| ) |  |

Sets image's mask so that the pixels that have RGB value of mr,mg,mb in mask will be masked in the image.

This is done by first finding an unused colour in the image, setting this colour as the mask colour and then using this colour to draw all pixels in the image who corresponding pixel in mask has given RGB value.

The parameter mask is the mask image to extract mask shape from. It must have the same dimensions as the image.

The parameters mr, mg, mb are the RGB values of the pixels in mask that will be used to create the mask.

Returns
  Returns false if mask does not have same dimensions as the image or if there is no unused colour left. Returns true if the mask was successfully applied.

Note
  Note that this method involves computing the histogram, which is a computationally intensive operation.

## ◆ SetOption() [1/2]

void wxImage::SetOption | ( | const wxString & | name,
|  | const wxString & | value
| ) |  |

Sets a user-defined option.

The function is case-insensitive to name.

For example, when saving as a JPEG file, the option quality is used, which is a number between 0 and 100 (0 is terrible, 100 is very good).

The lists of the currently supported options are in GetOption() and GetOptionInt() function docs.

See also
  GetOption(), GetOptionInt(), HasOption()

## ◆ SetOption() [2/2]

void wxImage::SetOption | ( | const wxString & | name,
|  | int | value
| ) |  |

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

## ◆ SetPalette()

void wxImage::SetPalette | ( | const wxPalette & | palette | ) |

Associates a palette with the image.

The palette may be used when converting wxImage to wxBitmap (MSW only at present) or in file save operations (none as yet).

## ◆ SetRGB() [1/2]

void wxImage::SetRGB | ( | const wxRect & | rect,
|  | unsigned char | red,
|  | unsigned char | green,
|  | unsigned char | blue
| ) |  |

Sets the colour of the pixels within the given rectangle.

This routine performs bounds-checks for the coordinate so it can be considered a safe way to manipulate the data.

## ◆ SetRGB() [2/2]

void wxImage::SetRGB | ( | int | x,
|  | int | y,
|  | unsigned char | r,
|  | unsigned char | g,
|  | unsigned char | b
| ) |  |

Set the color of the pixel at the given x and y coordinate.

## ◆ SetType()

void wxImage::SetType | ( | wxBitmapType | type | ) |

Set the type of image returned by GetType().

This method is mostly used internally by the library but can also be called from the user code if the image was created from data in the given bitmap format without using LoadFile() (which would set the type correctly automatically).

Notice that the image must be created before this function is called.

Since
  2.9.0

Parameters

  type | One of bitmap type constants, `wxBITMAP_TYPE_INVALID` is a valid value for it and can be used to reset the bitmap type to default but `wxBITMAP_TYPE_MAX` is not allowed here.

## ◆ Size()

wxImage wxImage::Size | ( | const wxSize & | size,
|  | const wxPoint & | pos,
|  | int | red = `-1`,
|  | int | green = `-1`,
|  | int | blue = `-1`
| ) |  | const

Returns a resized version of this image without scaling it by adding either a border with the given colour or cropping as necessary.

The image is pasted into a new image with the given size and background colour at the position pos relative to the upper left of the new image.

If red = green = blue = -1 then the areas of the larger image not covered by this image are made transparent by filling them with the image mask colour (which will be allocated automatically if it isn't currently set).

Otherwise, the areas will be filled with the colour with the specified RGB components.

See also
  Resize()