## wxImage

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.

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.

Unlike RGB data, not all images have an alpha channel and before using GetAlpha you should check if this image contains an alpha channel with HasAlpha. Note that currently only images loaded from PNG files with transparency information will have an alpha channel but alpha support will be added to the other formats as well (as well as support for saving images with alpha channel which also isn't implemented).

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 and saving, always installed.
wxPNGHandler | For loading (including alpha support) and saving.
wxJPEGHandler | For loading and saving.
wxGIFHandler | Only for loading, due to legal issues.
wxPCXHandler | For loading and saving (see below).
wxPNMHandler | For loading and saving (see below).
wxTIFFHandler | For loading and saving.
wxTGAHandler | For loading only.
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.

Derived from

wxObject

Include files

<wx/image.h>

See also

wxBitmap, wxInitAllImageHandlers

Members

wxImage::wxImage
wxImage::~wxImage
wxImage::AddHandler
wxImage::Blur
wxImage::BlurHorizontal
wxImage::BlurVertical
wxImage::CleanUpHandlers
wxImage::ComputeHistogram
wxImage::ConvertAlphaToMask
wxImage::ConvertToBitmap
wxImage::ConvertToGreyscale
wxImage::ConvertToMono
wxImage::Copy
wxImage::Create
wxImage::Destroy
wxImage::FindFirstUnusedColour
wxImage::FindHandler
wxImage::GetImageExtWildcard
wxImage::GetAlpha
wxImage::GetBlue
wxImage::GetData
wxImage::GetGreen
wxImage::GetImageCount
wxImage::GetHandlers
wxImage::GetHeight
wxImage::GetMaskBlue
wxImage::GetMaskGreen
wxImage::GetMaskRed
wxImage::GetOrFindMaskColour
wxImage::GetPalette
wxImage::GetRed
wxImage::GetSubImage
wxImage::GetWidth
HSVValue::HSVValue
wxImage::HSVtoRGB
wxImage::HasAlpha
wxImage::HasMask
wxImage::GetOption
wxImage::GetOptionInt
wxImage::HasOption
wxImage::InitAlpha
wxImage::InitStandardHandlers
wxImage::InsertHandler
wxImage::IsTransparent
wxImage::LoadFile
wxImage::IsOk
RGBValue::RGBValue
wxImage::RGBtoHSV
wxImage::RemoveHandler
wxImage::Mirror
wxImage::Replace
wxImage::Rescale
wxImage::Resize
wxImage::Rotate
wxImage::RotateHue
wxImage::Rotate90
wxImage::SaveFile
wxImage::Scale
wxImage::Size
wxImage::SetAlpha
wxImage::SetData
wxImage::SetMask
wxImage::SetMaskColour
wxImage::SetMaskFromImage
wxImage::SetOption
wxImage::SetPalette
wxImage::SetRGB
wxImage::SetRGB
wxImage::operator =

### wxImage::wxImage

wxImage()

Default constructor.

wxImage(const wxImage& image)

Copy constructor, uses reference counting.

wxImage(const wxBitmap& bitmap)

(Deprecated form, use wxBitmap::ConvertToImage instead.) Constructs an image from a platform-dependent bitmap. This preserves mask information so that bitmaps and images can be converted back and forth without loss in that respect.

wxImage(int width, int height, bool clear=true)

Creates an image with the given width and height. If clear is true, the new image will be initialized to black. Otherwise, the image data will be uninitialized.

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

Creates an image from given data with the given width and height. If static_data is true, then wxImage will not delete the actual image data in its destructor, otherwise it will free it by calling free().

wxImage(const wxString& name, long type = wxBITMAP_TYPE_ANY, int index = -1)

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

Loads an image from a file.

wxImage(wxInputStream& stream, long type = wxBITMAP_TYPE_ANY, int index = -1)

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

Loads an image from an input stream.

wxImage(const char* const* xpmData)

Creates an image from XPM data.

Parameters

width

Specifies the width of the image.

height

Specifies the height of the image.

name

Name of the file from which to load the image.

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_TIF | 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.

mimetype

MIME type string (for example 'image/jpeg')

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.

xpmData

A pointer to XPM image data.

Remarks

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

Note: any handler other than BMP must be previously initialized with wxImage::AddHandler or wxInitAllImageHandlers.

Note: you can use GetOptionInt to get the hotspot for loaded cursor file:

        int hotspot_x = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_X);
        int hotspot_y = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_Y);

See also

wxImage::LoadFile

wxPython note: Constructors supported by wxPython are:

wxImage(name, flag) | Loads an image from a file
wxNullImage() | Create a null image (has no size or image data)
wxEmptyImage(width, height) | Creates an empty image of the given size
wxImageFromMime(name, mimetype | Creates an image from the given file of the given mimetype
wxImageFromBitmap(bitmap) | Creates an image from a platform-dependent bitmap

wxPerl note: Constructors supported by wxPerl are:

- Wx::Image->new( bitmap )
- Wx::Image->new( icon )
- Wx::Image->new( width, height )
- Wx::Image->new( width, height, data )
- Wx::Image->new( file, type, index )
- Wx::Image->new( file, mimetype, index )
- Wx::Image->new( stream, type, index )
- Wx::Image->new( stream, mimetype, index )

### wxImage::~wxImage

~wxImage()

Destructor. See reference-counted object destruction for more info.

### wxImage::AddHandler

static void AddHandler(wxImageHandler* handler)

Adds a handler to the end of the static list of format handlers.

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

bool CanRead(const wxString& filename)

returns true if the current image handlers can read this file

wxPython note: In wxPython this static method is named `wxImage_AddHandler`.

### wxImage::Blur

wxImage Blur(int blurRadius)

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

### wxImage::BlurHorizontal

wxImage BlurHorizontal(int blurRadius)

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

### wxImage::BlurVertical

wxImage BlurVertical(int blurRadius)

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

### wxImage::CleanUpHandlers

static void CleanUpHandlers()

Deletes all image handlers.

This function is called by wxWidgets on exit.

### wxImage::ComputeHistogram

unsigned long 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);

Return value

Returns number of colours in the histogram.

### wxImage::ConvertAlphaToMask

bool ConvertAlphaToMask(unsigned char threshold = 128)

If the image has alpha channel, this method converts it to mask. All pixels with alpha value less than threshold are replaced with mask colour and the alpha channel is removed. Mask colour is chosen automatically using FindFirstUnusedColour.

If the image image doesn't have alpha channel, ConvertAlphaToMask does nothing.

Return value

`false` if FindFirstUnusedColour returns `false`, `true` otherwise.

### wxImage::ConvertToBitmap

wxBitmap ConvertToBitmap() const

Deprecated, use equivalent wxBitmap constructor (which takes wxImage and depth as its arguments) instead.

### wxImage::ConvertToGreyscale

wxImage ConvertToGreyscale(double lr = 0.299, double lg = 0.587, double lb = 0.114) 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 ITU-T BT.601 when converting to YUV, where every pixel equals (R * lr) + (G * lg) + (B * lb).

### wxImage::ConvertToMono

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.

### wxImage::Copy

wxImage Copy() const

Returns an identical copy of the image.

### wxImage::Create

bool Create(int width, int height, bool clear=true)

Creates a fresh image. If clear is true, the new image will be initialized to black. Otherwise, the image data will be uninitialized.

Parameters

width

The width of the image in pixels.

height

The height of the image in pixels.

Return value

true if the call succeeded, false otherwise.

### wxImage::Destroy

void Destroy()

Destroys the image data.

### wxImage::FindFirstUnusedColour

bool FindFirstUnusedColour(unsigned char * r, unsigned char * g, unsigned char * b, unsigned char startR = 1, unsigned char startG = 0, unsigned char startB = 0)

Parameters

r,g,b

Pointers to variables to save the colour.

startR,startG,startB

Initial values of the colour. Returned colour will have RGB values equal to or greater than these.

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.

Return value

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

Notes

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

### wxImage::FindHandler

static wxImageHandler* FindHandler(const wxString& name)

Finds the handler with the given name.

static wxImageHandler* FindHandler(const wxString& extension, long imageType)

Finds the handler associated with the given extension and type.

static wxImageHandler* FindHandler(long imageType)

Finds the handler associated with the given image type.

static wxImageHandler* FindHandlerMime(const wxString& mimetype)

Finds the handler associated with the given MIME type.

name

The handler name.

extension

The file extension, such as "bmp".

imageType

The image type, such as wxBITMAP_TYPE_BMP.

mimetype

MIME type.

Return value

A pointer to the handler if found, NULL otherwise.

See also

wxImageHandler

### wxImage::GetImageExtWildcard

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.

Return value

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 );

See also

wxImageHandler

### wxImage::GetAlpha

unsigned char GetAlpha(int x, int y) const

Returns the alpha value for the given pixel. This function may only be called for the images with alpha channel, use HasAlpha to check for this.

The returned value is the opacity of the image, i.e. the value of 0 corresponds to the transparent pixels while the value of 255 -- to the opaque ones.

unsigned char * 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.

### wxImage::GetBlue

unsigned char GetBlue(int x, int y) const

Returns the blue intensity at the given coordinate.

### wxImage::GetData

unsigned char* 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 pixel 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 wxImage::SetData.

### wxImage::GetGreen

unsigned char GetGreen(int x, int y) const

Returns the green intensity at the given coordinate.

### wxImage::GetImageCount

static int GetImageCount(const wxString& filename, long type = wxBITMAP_TYPE_ANY)

static int GetImageCount(wxInputStream& stream, long 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.

name

Name of the file to query.

stream

Opened input stream with image data. 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_TIF | Load a TIFF 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.

Return value

Number of available images. For most image handlers, this is 1 (exceptions are TIFF and ICO formats).

### wxImage::GetHandlers

static wxList& GetHandlers()

Returns the static list of image format handlers.

See also

wxImageHandler

### wxImage::GetHeight

int GetHeight() const

Gets the height of the image in pixels.

### wxImage::GetMaskBlue

unsigned char GetMaskBlue() const

Gets the blue value of the mask colour.

### wxImage::GetMaskGreen

unsigned char GetMaskGreen() const

Gets the green value of the mask colour.

### wxImage::GetMaskRed

unsigned char GetMaskRed() const

Gets the red value of the mask colour.

### wxImage::GetOrFindMaskColour

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. Returns `true` if the image currently has a mask.

### wxImage::GetPalette

const wxPalette& 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).

### wxImage::GetRed

unsigned char GetRed(int x, int y) const

Returns the red intensity at the given coordinate.

### wxImage::GetSubImage

wxImage GetSubImage(const wxRect& rect) const

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

### wxImage::GetWidth

int GetWidth() const

Gets the width of the image in pixels.

See also

wxImage::GetHeight

### HSVValue::HSVValue

HSVValue(double h = 0.0, double s = 0.0, double v = 0.0)

Constructor for HSVValue, an object that contains values for hue, saturation and value which represent the value of a color. It is used by wxImage::HSVtoRGB and wxImage::RGBtoHSV, which converts between HSV color space and RGB color space.

wxPython note: use wxImage_HSVValue in wxPython

### wxImage::HSVtoRGB

wxImage::RGBValue HSVtoRGB(const HSVValue & hsv)

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

### wxImage::HasAlpha

bool HasAlpha() const

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

See also

GetAlpha, SetAlpha

### wxImage::HasMask

bool HasMask() const

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

### wxImage::GetOption

wxString GetOption(const wxString& name) const

Gets 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).

See also

wxImage::SetOption, wxImage::GetOptionInt, wxImage::HasOption

### wxImage::GetOptionInt

int GetOptionInt(const wxString& name) const

Gets a user-defined option as an integer. The function is case-insensitive to name.

If the given option is not present, the function returns 0. Use wxImage::HasOption is 0 is a possibly valid value for the option.

Options for wxPNGHandler

wxIMAGE_OPTION_PNG_FORMAT | Format for saving a PNG file.
wxIMAGE_OPTION_PNG_BITDEPTH | Bit depth for every channel (R/G/B/A).

Supported values for wxIMAGE_OPTION_PNG_FORMAT:

wxPNG_TYPE_COLOUR | Stores RGB image.
wxPNG_TYPE_GREY | Stores grey image, converts from RGB.
wxPNG_TYPE_GREY_RED | Stores grey image, uses red value as grey.

See also

wxImage::SetOption, wxImage::GetOption

### wxImage::HasOption

bool HasOption(const wxString& name) const

Returns true if the given option is present. The function is case-insensitive to name.

See also

wxImage::SetOption, wxImage::GetOption, wxImage::GetOptionInt

### wxImage::InitAlpha

void 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 a mask colour, all mask pixels will be completely transparent.

### wxImage::InitStandardHandlers

static void InitStandardHandlers()

Internal use only. Adds standard image format handlers. It only install BMP 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

### wxImage::InsertHandler

static void InsertHandler(wxImageHandler* handler)

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

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

### wxImage::IsTransparent

bool IsTransparent(int x, int y, unsigned char threshold = 128) 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.

### wxImage::LoadFile

bool LoadFile(const wxString& name, long type = wxBITMAP_TYPE_ANY, int index = -1)

bool LoadFile(const wxString& name, const wxString& mimetype, int index = -1)

Loads an image from a file. If no handler type is provided, the library will try to autodetect the format.

bool LoadFile(wxInputStream& stream, long type, int index = -1)

bool LoadFile(wxInputStream& stream, const wxString& mimetype, int index = -1)

Loads an image from an input stream.

Parameters

name

Name of the file from which to load the image.

stream

Opened input stream from which to load the image. Currently, the stream must support seeking.

type

One of the following values:

wxBITMAP_TYPE_BMP | Load a Windows image file.
wxBITMAP_TYPE_GIF | Load a GIF image file.
wxBITMAP_TYPE_JPEG | Load a JPEG image file.
wxBITMAP_TYPE_PCX | Load a PCX image file.
wxBITMAP_TYPE_PNG | Load a PNG image file.
wxBITMAP_TYPE_PNM | Load a PNM image file.
wxBITMAP_TYPE_TIF | Load a TIFF image file.
wxBITMAP_TYPE_XPM | Load a XPM image 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.

mimetype

MIME type string (for example 'image/jpeg')

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, not all formats may be available.

Note: you can use GetOptionInt to get the hotspot for loaded cursor file:

        int hotspot_x = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_X);
        int hotspot_y = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_Y);

Return value

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.

See also

wxImage::SaveFile

wxPython note: In place of a single overloaded method name, wxPython implements the following methods:

LoadFile(filename, type) | Loads an image of the given type from a file
LoadMimeFile(filename, mimetype) | Loads an image of the given mimetype from a file

wxPerl note: Methods supported by wxPerl are:

- bitmap->LoadFile( name, type )
- bitmap->LoadFile( name, mimetype )

### wxImage::IsOk

bool IsOk() const

Returns true if image data is present.

### RGBValue::RGBValue

RGBValue(unsigned char r = 0, unsigned char g = 0, unsigned char b = 0)

Constructor for RGBValue, an object that contains values for red, green and blue which represent the value of a color. It is used by wxImage::HSVtoRGB and wxImage::RGBtoHSV, which converts between HSV color space and RGB color space.

wxPython note: use wxImage_RGBValue in wxPython

### wxImage::RGBtoHSV

wxImage::HSVValue RGBtoHSV(const RGBValue& rgb)

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

### wxImage::RemoveHandler

static bool RemoveHandler(const wxString& name)

Finds the handler with the given name, and removes it. The handler is not deleted.

name

The handler name.

Return value

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

See also

wxImageHandler

### wxImage::Mirror

wxImage Mirror(bool horizontally = true) const

Returns a mirrored copy of the image. The parameter horizontally indicates the orientation.

### wxImage::Replace

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.

### wxImage::Rescale

wxImage & Rescale(int width, int height, int 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

### wxImage::Resize

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

### wxImage::Rotate

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

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.

### wxImage::RotateHue

void RotateHue(double angle)

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

### wxImage::Rotate90

wxImage Rotate90(bool clockwise = true) const

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

### wxImage::SaveFile

bool SaveFile(const wxString& name, int type) const

bool SaveFile(const wxString& name, const wxString& mimetype) const

Saves an image in the named file.

bool SaveFile(const wxString& name) const

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.

bool SaveFile(wxOutputStream& stream, int type) const

bool SaveFile(wxOutputStream& stream, const wxString& mimetype) const

Saves an image in the given stream.

Parameters

name

Name of the file to save the image to.

stream

Opened output stream 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).

mimetype

MIME type.

Return value

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 GetOptionInt to set the hotspot before 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

wxImage::LoadFile

wxPython note: In place of a single overloaded method name, wxPython implements the following methods:

SaveFile(filename, type) | Saves the image using the given type to the named file
SaveMimeFile(filename, mimetype) | Saves the image using the given mimetype to the named file

wxPerl note: Methods supported by wxPerl are:

- bitmap->SaveFile( name, type )
- bitmap->SaveFile( name, mimetype )

### wxImage::Scale

wxImage Scale(int width, int height, int 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.

quality

Determines what method to use for resampling the image. Can be one of the following:

wxIMAGE_QUALITY_NORMAL | Uses the normal default scaling method of pixel replication
wxIMAGE_QUALITY_HIGH | Uses bicubic and box averaging resampling methods for upsampling and downsampling respectively

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;
        }

See also

Rescale

### wxImage::Size

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 use either the current mask colour if set or find, use, and set a suitable mask colour for any newly exposed areas.

See also

Resize

### wxImage::SetAlpha

void 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.

void 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.

### wxImage::SetData

void SetData(unsigned char*data)

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`.

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 wxImage::GetData.

### wxImage::SetMask

void SetMask(bool hasMask = true)

Specifies whether there is a mask or not. The area of the mask is determined by the current mask colour.

### wxImage::SetMaskColour

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).

### wxImage::SetMaskFromImage

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

Parameters

mask

The mask image to extract mask shape from. Must have same dimensions as the image.

mr,mg,mb

RGB value of pixels in mask that will be used to create the mask.

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.

Return value

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.

Notes

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

### wxImage::SetOption

void SetOption(const wxString& name, const wxString& value)

void SetOption(const wxString& name, int 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).

See also

wxImage::GetOption, wxImage::GetOptionInt, wxImage::HasOption

### wxImage::SetPalette

void 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).

### wxImage::SetRGB

void SetRGB(int x, int y, unsigned char red, unsigned char green, unsigned char blue)

Sets the pixel at the given coordinate. This routine performs bounds-checks for the coordinate so it can be considered a safe way to manipulate the data, but in some cases this might be too slow so that the data will have to be set directly. In that case you will have to get access to the image data using the GetData method.

### wxImage::SetRGB

void SetRGB(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.

### wxImage::operator =

wxImage& operator =(const wxImage& image)

Assignment operator, using reference counting.

Parameters

image

Image to assign.

Return value

Returns 'this' object.