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wxWidgets/interface/wx/image.h
Vadim Zeitlin 90fbb09ae2 Add wxImage::ClearAlpha(). 
This simple method can be used to remove alpha channel from the image.

See #10915.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63922 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
2010-04-09 13:15:20 +00:00

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/////////////////////////////////////////////////////////////////////////////
// Name: image.h
// Purpose: interface of wxImageHandler and wxImage
// Author: wxWidgets team
// RCS-ID: $Id$
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
/**
Possible values for the image resolution option.
@see wxImage::GetOptionInt().
*/
enum wxImageResolution
{
/// Resolution not specified.
wxIMAGE_RESOLUTION_NONE = 0,
/// Resolution specified in inches.
wxIMAGE_RESOLUTION_INCHES = 1,
/// Resolution specified in centimetres.
wxIMAGE_RESOLUTION_CM = 2
};
/**
Image resize algorithm.
This is used with wxImage::Scale() and wxImage::Rescale().
*/
enum wxImageResizeQuality
{
/// Simplest and fastest algorithm.
wxIMAGE_QUALITY_NEAREST,
/// Compromise between wxIMAGE_QUALITY_NEAREST and wxIMAGE_QUALITY_BICUBIC.
wxIMAGE_QUALITY_BILINEAR,
/// Highest quality but slowest execution time.
wxIMAGE_QUALITY_BICUBIC,
/// Default image resizing algorithm used by wxImage::Scale().
wxIMAGE_QUALITY_NORMAL,
/// Best image resizing algorithm, currently same as wxIMAGE_QUALITY_BICUBIC.
wxIMAGE_QUALITY_HIGH
};
/**
Possible values for PNG image type option.
@see wxImage::GetOptionInt().
*/
enum wxImagePNGType
{
wxPNG_TYPE_COLOUR = 0, ///< Colour PNG image.
wxPNG_TYPE_GREY = 2, ///< Greyscale PNG image converted from RGB.
wxPNG_TYPE_GREY_RED = 3 ///< Greyscale PNG image using red as grey.
};
/**
@class wxImageHandler
This is the base class for implementing image file loading/saving, and
image creation from data.
It is used within wxImage and is not normally seen by the application.
If you wish to extend the capabilities of wxImage, derive a class from
wxImageHandler and add the handler using wxImage::AddHandler in your
application initialization.
Note that all wxImageHandlers provided by wxWidgets are part of
the @ref page_libs_wxcore library.
For details about the default handlers, please see the section
@ref image_handlers in the wxImage class documentation.
@section imagehandler_note Note (Legal Issue)
This software is based in part on the work of the Independent JPEG Group.
(Applies when wxWidgets is linked with JPEG support.
wxJPEGHandler uses libjpeg created by IJG.)
@stdobjects
::wxNullImage
@library{wxcore}
@category{gdi}
@see wxImage, wxInitAllImageHandlers()
*/
class wxImageHandler : public wxObject
{
public:
/**
Default constructor.
In your own default constructor, initialise the members
m_name, m_extension and m_type.
*/
wxImageHandler();
/**
Destroys the wxImageHandler object.
*/
virtual ~wxImageHandler();
/**
Returns @true if this handler supports the image format contained in the
given stream.
This function doesn't modify the current stream position (because it
restores the original position before returning; this however requires the
stream to be seekable; see wxStreamBase::IsSeekable).
*/
bool CanRead( wxInputStream& stream );
/**
Returns @true if this handler supports the image format contained in the
file with the given name.
This function doesn't modify the current stream position (because it
restores the original position before returning; this however requires the
stream to be seekable; see wxStreamBase::IsSeekable).
*/
bool CanRead( const wxString& filename );
/**
Gets the preferred file extension associated with this handler.
@see GetAltExtensions()
*/
const wxString& GetExtension() const;
/**
Returns the other file extensions associated with this handler.
The preferred extension for this handler is returned by GetExtension().
@since 2.9.0
*/
const wxArrayString& GetAltExtensions() const;
/**
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.
@param stream
Opened input stream for reading image data.
This function doesn't modify the current stream position (because it
restores the original position before returning; this however requires the
stream to be seekable; see wxStreamBase::IsSeekable).
@return 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).
*/
virtual int GetImageCount(wxInputStream& stream);
/**
Gets the MIME type associated with this handler.
*/
const wxString& GetMimeType() const;
/**
Gets the name of this handler.
*/
const wxString& GetName() const;
/**
Gets the image type associated with this handler.
*/
wxBitmapType GetType() const;
/**
Loads a image from a stream, putting the resulting data into @a image.
If the image file contains more than one image and the image handler is
capable of retrieving these individually, @a index indicates which image
to read from the stream.
@param image
The image object which is to be affected by this operation.
@param stream
Opened input stream for reading image data.
@param verbose
If set to @true, errors reported by the image handler will produce
wxLogMessages.
@param index
The index of the image in the file (starting from zero).
@return @true if the operation succeeded, @false otherwise.
@see wxImage::LoadFile, wxImage::SaveFile, SaveFile()
*/
virtual bool LoadFile(wxImage* image, wxInputStream& stream,
bool verbose = true, int index = -1);
/**
Saves a image in the output stream.
@param image
The image object which is to be affected by this operation.
@param stream
Opened output stream for writing the data.
@param verbose
If set to @true, errors reported by the image handler will produce
wxLogMessages.
@return @true if the operation succeeded, @false otherwise.
@see wxImage::LoadFile, wxImage::SaveFile, LoadFile()
*/
virtual bool SaveFile(wxImage* image, wxOutputStream& stream,
bool verbose = true);
/**
Sets the preferred file extension associated with this handler.
@param extension
File extension without leading dot.
@see SetAltExtensions()
*/
void SetExtension(const wxString& extension);
/**
Sets the alternative file extensions associated with this handler.
@param extensions
Array of file extensions.
@see SetExtension()
@since 2.9.0
*/
void SetAltExtensions(const wxArrayString& extensions);
/**
Sets the handler MIME type.
@param mimetype
Handler MIME type.
*/
void SetMimeType(const wxString& mimetype);
/**
Sets the handler name.
@param name
Handler name.
*/
void SetName(const wxString& name);
};
/**
Constant used to indicate the alpha value conventionally defined as
the complete transparency.
*/
const unsigned char wxIMAGE_ALPHA_TRANSPARENT = 0;
/**
Constant used to indicate the alpha value conventionally defined as
the complete opacity.
*/
const unsigned char wxIMAGE_ALPHA_OPAQUE = 0xff;
/**
@class 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.
@section image_alpha 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. Note that currently only the PNG format has
full alpha channel support so only the images loaded from PNG files can have
alpha and, if you initialize the image alpha channel yourself using
wxImage::SetAlpha, you should save it in PNG format to avoid losing it.
@section image_handlers 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.
@library{wxcore}
@category{gdi}
@stdobjects
::wxNullImage
@see wxBitmap, wxInitAllImageHandlers(), wxPixelData
*/
class wxImage : public wxObject
{
public:
/**
A simple class which stores red, green and blue values as 8 bit unsigned integers
in the range of 0-255.
*/
class RGBValue
{
public:
/**
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 convert
between HSV color space and RGB color space.
*/
RGBValue(unsigned char r=0, unsigned char g=0, unsigned char b=0);
};
/**
A simple class which stores hue, saturation and value as doubles in the range 0.0-1.0.
*/
class HSVValue
{
public:
/**
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 convert
between HSV color space and RGB color space.
*/
HSVValue(double h=0.0, double s=0.0, double v=0.0);
};
/**
Creates an empty wxImage object without an alpha channel.
*/
wxImage();
/**
Creates an image with the given size and clears it if requested.
Does not create an alpha channel.
@param width
Specifies the width of the image.
@param height
Specifies the height of the image.
@param clear
If @true, initialize the image to black.
*/
wxImage(int width, int height, bool clear = true);
/**
@overload
*/
wxImage(const wxSize& sz, bool clear = true);
/**
Creates an image from data in memory. If @a 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 @e malloc.
@param width
Specifies the width of the image.
@param height
Specifies the height of the image.
@param data
A pointer to RGB data
@param static_data
Indicates if the data should be free'd after use
*/
wxImage(int width, int height, unsigned char* data, bool static_data = false);
/**
@overload
*/
wxImage(const wxSize& sz, unsigned char* data, bool static_data = false);
/**
Creates an image from data in memory. If @a 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 @e malloc.
@param width
Specifies the width of the image.
@param height
Specifies the height of the image.
@param data
A pointer to RGB data
@param alpha
A pointer to alpha-channel data
@param static_data
Indicates if the data should be free'd after use
*/
wxImage(int width, int height, unsigned char* data, unsigned char* alpha,
bool static_data = false );
/**
@overload
*/
wxImage(const wxSize& sz, unsigned char* data, unsigned char* data, unsigned char* alpha,
bool static_data = false);
/**
Creates an image from XPM data.
@param xpmData
A pointer to XPM image data.
@beginWxPerlOnly
Not supported by wxPerl.
@endWxPerlOnly
*/
wxImage(const char* const* xpmData);
/**
Creates an image from a file.
@param name
Name of the file from which to load the image.
@param type
May be one of the following:
@li wxBITMAP_TYPE_BMP: Load a Windows bitmap file.
@li wxBITMAP_TYPE_GIF: Load a GIF bitmap file.
@li wxBITMAP_TYPE_JPEG: Load a JPEG bitmap file.
@li wxBITMAP_TYPE_PNG: Load a PNG bitmap file.
@li wxBITMAP_TYPE_PCX: Load a PCX bitmap file.
@li wxBITMAP_TYPE_PNM: Load a PNM bitmap file.
@li wxBITMAP_TYPE_TIF: Load a TIFF bitmap file.
@li wxBITMAP_TYPE_TGA: Load a TGA bitmap file.
@li wxBITMAP_TYPE_XPM: Load a XPM bitmap file.
@li wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO).
@li wxBITMAP_TYPE_CUR: Load a Windows cursor file (CUR).
@li wxBITMAP_TYPE_ANI: Load a Windows animated cursor file (ANI).
@li wxBITMAP_TYPE_ANY: Will try to autodetect the format.
@param 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:
@code
int hotspot_x = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_X);
int hotspot_y = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_Y);
@endcode
@see LoadFile()
*/
wxImage(const wxString& name, wxBitmapType type = wxBITMAP_TYPE_ANY, int index = -1);
/**
Creates an image from a file using MIME-types to specify the type.
@param name
Name of the file from which to load the image.
@param mimetype
MIME type string (for example 'image/jpeg')
@param index
See description in wxImage(const wxString&, wxBitmapType, int) overload.
*/
wxImage(const wxString& name, const wxString& mimetype, int index = -1);
/**
Creates an image from a stream.
@param stream
Opened input stream from which to load the image. Currently,
the stream must support seeking.
@param type
See description in wxImage(const wxString&, wxBitmapType, int) overload.
@param index
See description in wxImage(const wxString&, wxBitmapType, int) overload.
*/
wxImage(wxInputStream& stream, wxBitmapType type = wxBITMAP_TYPE_ANY, int index = -1);
/**
Creates an image from a stream using MIME-types to specify the type.
@param stream
Opened input stream from which to load the image. Currently,
the stream must support seeking.
@param mimetype
MIME type string (for example 'image/jpeg')
@param index
See description in wxImage(const wxString&, wxBitmapType, int) overload.
*/
wxImage(wxInputStream& stream, const wxString& mimetype, int index = -1);
/**
Destructor.
See @ref overview_refcount_destruct "reference-counted object destruction"
for more info.
*/
virtual ~wxImage();
/**
@name Image creation, initialization and deletion functions
*/
//@{
/**
Returns an identical copy of this image.
*/
wxImage Copy() const;
/**
Creates a fresh image.
See wxImage::wxImage(int,int,bool) for more info.
@return @true if the call succeeded, @false otherwise.
*/
bool Create(int width, int height, bool clear = true);
/**
@overload
*/
bool Create( const wxSize& sz, bool clear = true );
/**
Creates a fresh image.
See wxImage::wxImage(int,int,unsigned char*,bool) for more info.
@return @true if the call succeeded, @false otherwise.
*/
bool Create( int width, int height, unsigned char* data, bool static_data = false );
/**
@overload
*/
bool Create( const wxSize& sz, unsigned char* data, bool static_data = false );
/**
Creates a fresh image.
See wxImage::wxImage(int,int,unsigned char*,unsigned char*,bool) for more info.
@return @true if the call succeeded, @false otherwise.
*/
bool Create( int width, int height, unsigned char* data, unsigned char* alpha, bool static_data = false );
/**
@overload
*/
bool Create( const wxSize& sz, unsigned char* data, unsigned char* alpha, bool static_data = false );
/**
Initialize the image data with zeroes (the default) or with the
byte value given as @a value.
@since 2.9.0
*/
void Clear(unsigned char value = 0);
/**
Destroys the image data.
*/
void Destroy();
/**
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.
*/
void InitAlpha();
//@}
/**
@name Image manipulation functions
*/
//@{
/**
Blurs the image in both horizontal and vertical directions by the
specified pixel @a blurRadius. This should not be used when using
a single mask colour for transparency.
@see BlurHorizontal(), BlurVertical()
*/
wxImage Blur(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 Blur(), BlurVertical()
*/
wxImage BlurHorizontal(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 Blur(), BlurHorizontal()
*/
wxImage BlurVertical(int blurRadius) const;
/**
Returns a mirrored copy of the image.
The parameter @a horizontally indicates the orientation.
*/
wxImage Mirror(bool horizontally = true) const;
/**
Copy the data of the given @a image to the specified position in this image.
*/
void Paste(const wxImage& image, int x, int y);
/**
Replaces the colour specified by @e r1,g1,b1 by the colour @e r2,g2,b2.
*/
void Replace(unsigned char r1, unsigned char g1,
unsigned char b1, unsigned char r2,
unsigned char g2, unsigned char b2);
/**
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 @a quality parameter, see the Scale() function.
Returns the (modified) image itself.
@see Scale()
*/
wxImage& Rescale(int width, int height,
wxImageResizeQuality quality = wxIMAGE_QUALITY_NORMAL);
/**
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 @a size and background
colour at the position @a pos relative to the upper left of the new image.
If @a 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.
@return The (modified) image itself.
@see Size()
*/
wxImage& Resize(const wxSize& size, const wxPoint& pos, int red = -1,
int green = -1, int blue = -1);
/**
Rotates the image about the given point, by @a angle radians.
Passing @true to @a 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 Rotate(double angle, const wxPoint& rotationCentre,
bool interpolating = true,
wxPoint* offsetAfterRotation = NULL) const;
/**
Returns a copy of the image rotated 90 degrees in the direction
indicated by @a clockwise.
*/
wxImage Rotate90(bool clockwise = true) const;
/**
Rotates the hue of each pixel in the image by @e 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.
*/
void RotateHue(double angle);
/**
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 @a quality determines what method to use for resampling
the image, see wxImageResizeQuality documentation.
It should be noted that although using @c 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:
@code
// 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;
}
@endcode
@see Rescale()
*/
wxImage Scale(int width, int height,
wxImageResizeQuality quality = wxIMAGE_QUALITY_NORMAL) 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 @a size and background
colour at the position @a pos relative to the upper left of the new image.
If @a 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 Resize()
*/
wxImage Size(const wxSize& size, const wxPoint& pos, int red = -1,
int green = -1, int blue = -1) const;
//@}
/**
@name Conversion functions
*/
//@{
/**
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 @a 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() by this function, see the overload below if you
this is not appropriate.
@return @false if FindFirstUnusedColour returns @false, @true otherwise.
*/
bool ConvertAlphaToMask(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 @a threshold are replaced with the mask colour and the alpha
channel is removed. Otherwise nothing is done.
@since 2.9.0
@param mr
The red component of the mask colour.
@param mg
The green component of the mask colour.
@param mb
The blue component of the mask colour.
@param 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.
*/
void ConvertAlphaToMask(unsigned char mr, unsigned char mg, unsigned char mb,
unsigned char threshold = wxIMAGE_ALPHA_THRESHOLD);
/**
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 * @a weight_r) + (G * @a weight_g) + (B * @a weight_b).
*/
wxImage ConvertToGreyscale(double weight_r, double weight_g, double weight_b) const;
/**
Returns a greyscale version of the image.
@since 2.9.0
*/
wxImage ConvertToGreyscale() const;
/**
Returns monochromatic version of the image.
The returned image has white colour where the original has @e (r,g,b)
colour and black colour everywhere else.
*/
wxImage ConvertToMono(unsigned char r, unsigned char g, unsigned char b) const;
/**
Returns disabled (dimmed) version of the image.
@since 2.9.0
*/
wxImage ConvertToDisabled(unsigned char brightness = 255) const;
//@}
/**
@name Miscellaneous functions
*/
//@{
/**
Computes the histogram of the image. @a histogram is a reference to
wxImageHistogram object. wxImageHistogram is a specialization of
wxHashMap "template" and is defined as follows:
@code
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);
@endcode
@return Returns number of colours in the histogram.
*/
unsigned long ComputeHistogram(wxImageHistogram& histogram) 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 @a r, @a g, @a b are pointers to variables to save the colour.
The parameters @a startR, @a startG, @a startB define the initial values
of the colour.
The returned colour will have RGB values equal to or greater than these.
@return 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.
*/
bool FindFirstUnusedColour(unsigned char* r, unsigned char* g,
unsigned char* b, unsigned char startR = 1,
unsigned char startG = 0,
unsigned char startB = 0) const;
/**
Assignment operator, using @ref overview_refcount "reference counting".
@param image
Image to assign.
@return Returns 'this' object.
*/
wxImage& operator=(const wxImage& image);
//@}
/**
@name Getters
*/
//@{
/**
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.
*/
unsigned char* GetAlpha() 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 SetData().
*/
unsigned char* GetData() const;
/**
Return alpha value at given pixel location.
*/
unsigned char GetAlpha(int x, int y) const;
/**
Returns the red intensity at the given coordinate.
*/
unsigned char GetRed(int x, int y) const;
/**
Returns the green intensity at the given coordinate.
*/
unsigned char GetGreen(int x, int y) const;
/**
Returns the blue intensity at the given coordinate.
*/
unsigned char GetBlue(int x, int y) const;
/**
Gets the red value of the mask colour.
*/
unsigned char GetMaskRed() const;
/**
Gets the green value of the mask colour.
*/
unsigned char GetMaskGreen() const;
/**
Gets the blue value of the mask colour.
*/
unsigned char GetMaskBlue() const;
/**
Gets the width of the image in pixels.
@see GetHeight(), GetSize()
*/
int GetWidth() const;
/**
Gets the height of the image in pixels.
@see GetWidth(), GetSize()
*/
int GetHeight() const;
/**
Returns the size of the image in pixels.
@since 2.9.0
@see GetHeight(), GetWidth()
*/
wxSize GetSize() const;
/**
Gets a user-defined string-valued option.
Currently the only defined string option is
@li @c wxIMAGE_OPTION_FILENAME: The name of the file from which the image
was loaded.
@param name
The name of the option, case-insensitive.
@return
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 SetOption(), GetOptionInt(), HasOption()
*/
wxString GetOption(const wxString& name) const;
/**
Gets a user-defined integer-valued option.
The function is case-insensitive to @a name.
If the given option is not present, the function returns 0.
Use HasOption() is 0 is a possibly valid value for the option.
Generic options:
@li @c wxIMAGE_OPTION_MAX_WIDTH and @c 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 @em 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.
@li @c 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.
@li @c 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.
@li @c wxIMAGE_OPTION_RESOLUTION, @c wxIMAGE_OPTION_RESOLUTIONX and
@c wxIMAGE_OPTION_RESOLUTIONY: These options define the resolution of
the image in the units corresponding to @c 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:
@li @c wxIMAGE_OPTION_PNG_FORMAT: Format for saving a PNG file, see
wxImagePNGType for the supported values.
@li @c wxIMAGE_OPTION_PNG_BITDEPTH: Bit depth for every channel (R/G/B/A).
@li @c 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).
@li @c wxIMAGE_OPTION_PNG_COMPRESSION_LEVEL: Compression level (0..9) for
saving a PNG file. An 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.
@li @c wxIMAGE_OPTION_PNG_COMPRESSION_MEM_LEVEL: Compression memory usage
level (1..9) for saving a PNG file. An high value means the saving
process consumes more memory, but may create smaller PNG file.
@li @c 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.
@li @c 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.
@param name
The name of the option, case-insensitive.
@return
The value of the option or 0 if not found.
Use HasOption() if 0 can be a valid option value.
@see SetOption(), GetOption()
*/
int GetOptionInt(const wxString& name) 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.
*/
bool GetOrFindMaskColour(unsigned char* r, unsigned char* g,
unsigned char* b) 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).
*/
const wxPalette& GetPalette() const;
/**
Returns a sub image of the current one as long as the rect belongs entirely
to the image.
*/
wxImage GetSubImage(const wxRect& rect) const;
/**
Gets the type of image found by LoadFile() or specified with SaveFile().
@since 2.9.0
*/
wxBitmapType GetType() const;
/**
Returns @true if this image has alpha channel, @false otherwise.
@see GetAlpha(), SetAlpha()
*/
bool HasAlpha() const;
/**
Returns @true if there is a mask active, @false otherwise.
*/
bool HasMask() const;
/**
Returns @true if the given option is present.
The function is case-insensitive to @a name.
The lists of the currently supported options are in GetOption() and
GetOptionInt() function docs.
@see SetOption(), GetOption(), GetOptionInt()
*/
bool HasOption(const wxString& name) const;
/**
Returns @true if image data is present.
*/
bool IsOk() 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 @a threshold.
*/
bool IsTransparent(int x, int y,
unsigned char threshold = wxIMAGE_ALPHA_THRESHOLD) const;
//@}
/**
@name Loading and saving functions
*/
//@{
/**
Loads an image from an input stream.
@param stream
Opened input stream from which to load the image.
Currently, the stream must support seeking.
@param type
May be one of the following:
@li wxBITMAP_TYPE_BMP: Load a Windows bitmap file.
@li wxBITMAP_TYPE_GIF: Load a GIF bitmap file.
@li wxBITMAP_TYPE_JPEG: Load a JPEG bitmap file.
@li wxBITMAP_TYPE_PNG: Load a PNG bitmap file.
@li wxBITMAP_TYPE_PCX: Load a PCX bitmap file.
@li wxBITMAP_TYPE_PNM: Load a PNM bitmap file.
@li wxBITMAP_TYPE_TIF: Load a TIFF bitmap file.
@li wxBITMAP_TYPE_TGA: Load a TGA bitmap file.
@li wxBITMAP_TYPE_XPM: Load a XPM bitmap file.
@li wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO).
@li wxBITMAP_TYPE_CUR: Load a Windows cursor file (CUR).
@li wxBITMAP_TYPE_ANI: Load a Windows animated cursor file (ANI).
@li wxBITMAP_TYPE_ANY: Will try to autodetect the format.
@param 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.
@return @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:
@code
int hotspot_x = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_X);
int hotspot_y = image.GetOptionInt(wxIMAGE_OPTION_CUR_HOTSPOT_Y);
@endcode
@see SaveFile()
*/
virtual bool LoadFile(wxInputStream& stream,
wxBitmapType type = wxBITMAP_TYPE_ANY,
int index = -1);
/**
Loads an image from a file.
If no handler type is provided, the library will try to autodetect the format.
@param name
Name of the file from which to load the image.
@param type
See the description in the LoadFile(wxInputStream&, wxBitmapType, int) overload.
@param index
See the description in the LoadFile(wxInputStream&, wxBitmapType, int) overload.
*/
virtual bool LoadFile(const wxString& name,
wxBitmapType type = wxBITMAP_TYPE_ANY,
int index = -1);
/**
Loads an image from a file.
If no handler type is provided, the library will try to autodetect the format.
@param name
Name of the file from which to load the image.
@param mimetype
MIME type string (for example 'image/jpeg')
@param index
See the description in the LoadFile(wxInputStream&, wxBitmapType, int) overload.
*/
virtual bool LoadFile(const wxString& name, const wxString& mimetype,
int index = -1);
/**
Loads an image from an input stream.
@param stream
Opened input stream from which to load the image.
Currently, the stream must support seeking.
@param mimetype
MIME type string (for example 'image/jpeg')
@param index
See the description in the LoadFile(wxInputStream&, wxBitmapType, int) overload.
*/
virtual bool LoadFile(wxInputStream& stream, const wxString& mimetype,
int index = -1);
/**
Saves an image in the given stream.
@param stream
Opened output stream to save the image to.
@param mimetype
MIME type.
@return @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):
@code
image.SetOption(wxIMAGE_OPTION_CUR_HOTSPOT_X, hotspotX);
image.SetOption(wxIMAGE_OPTION_CUR_HOTSPOT_Y, hotspotY);
@endcode
@see LoadFile()
*/
virtual bool SaveFile(wxOutputStream& stream,
const wxString& mimetype) const;
/**
Saves an image in the named file.
@param name
Name of the file to save the image to.
@param type
Currently these types can be used:
@li wxBITMAP_TYPE_BMP: Save a BMP image file.
@li wxBITMAP_TYPE_JPEG: Save a JPEG image file.
@li wxBITMAP_TYPE_PNG: Save a PNG image file.
@li wxBITMAP_TYPE_PCX: Save a PCX image file
(tries to save as 8-bit if possible, falls back to 24-bit otherwise).
@li wxBITMAP_TYPE_PNM: Save a PNM image file (as raw RGB always).
@li wxBITMAP_TYPE_TIFF: Save a TIFF image file.
@li wxBITMAP_TYPE_XPM: Save a XPM image file.
@li 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.
@li wxBITMAP_TYPE_CUR: Save a Windows cursor file (CUR).
*/
virtual bool SaveFile(const wxString& name, wxBitmapType type) const;
/**
Saves an image in the named file.
@param name
Name of the file to save the image to.
@param mimetype
MIME type.
*/
virtual bool SaveFile(const wxString& name, const wxString& mimetype) 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.
@param name
Name of the file to save the image to.
*/
virtual bool SaveFile(const wxString& name) const;
/**
Saves an image in the given stream.
@param stream
Opened output stream to save the image to.
@param type
MIME type.
*/
virtual bool SaveFile(wxOutputStream& stream, wxBitmapType type) const;
//@}
/**
@name Setters
*/
//@{
/**
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 @a static_data
parameter is set to @true -- in this case the caller should do it.
*/
void SetAlpha(unsigned char* alpha = NULL,
bool static_data = false);
/**
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.
*/
void SetAlpha(int x, int y, unsigned char alpha);
/**
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
*/
void ClearAlpha();
/**
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 @c malloc(), @b NOT with
@c operator new.
If @a 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().
*/
void SetData(unsigned char* data, bool static_data = false);
/**
@overload
*/
void SetData(unsigned char* data, int new_width, int new_height,
bool static_data = false);
/**
Specifies whether there is a mask or not.
The area of the mask is determined by the current mask colour.
*/
void SetMask(bool hasMask = true);
/**
Sets the mask colour for this image (and tells the image to use the mask).
*/
void SetMaskColour(unsigned char red, unsigned char green,
unsigned char blue);
/**
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 @a mask is the mask image to extract mask shape from.
It must have the same dimensions as the image.
The parameters @a mr, @a mg, @a mb are the RGB values of the pixels in
mask that will be used to create the mask.
@return 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.
*/
bool SetMaskFromImage(const wxImage& mask, unsigned char mr,
unsigned char mg,
unsigned char mb);
/**
Sets a user-defined option. The function is case-insensitive to @a name.
For example, when saving as a JPEG file, the option @b 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 GetOption(), GetOptionInt(), HasOption()
*/
void SetOption(const wxString& name, const wxString& value);
/**
@overload
*/
void SetOption(const wxString& name, int value);
/**
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).
*/
void SetPalette(const wxPalette& palette);
/**
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.
*/
void SetRGB(const wxRect& rect,
unsigned char red,
unsigned char green,
unsigned char blue);
/**
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
@param type
One of bitmap type constants, @c wxBITMAP_TYPE_INVALID is a valid
value for it and can be used to reset the bitmap type to default
but @c wxBITMAP_TYPE_MAX is not allowed here.
*/
void SetType(wxBitmapType type);
//@}
/**
@name Handler management functions
*/
//@{
/**
Register an image handler.
See @ref image_handlers for a list of the available handlers.
*/
static void AddHandler(wxImageHandler* handler);
/**
Deletes all image handlers.
This function is called by wxWidgets on exit.
*/
static void CleanUpHandlers();
/**
Finds the handler with the given name.
@param name
The handler name.
@return A pointer to the handler if found, @NULL otherwise.
@see wxImageHandler
*/
static wxImageHandler* FindHandler(const wxString& name);
/**
Finds the handler associated with the given extension and type.
@param extension
The file extension, such as "bmp".
@param imageType
The image type; one of the ::wxBitmapType values.
@return A pointer to the handler if found, @NULL otherwise.
@see wxImageHandler
*/
static wxImageHandler* FindHandler(const wxString& extension,
wxBitmapType imageType);
/**
Finds the handler associated with the given image type.
@param imageType
The image type; one of the ::wxBitmapType values.
@return A pointer to the handler if found, @NULL otherwise.
@see wxImageHandler
*/
static wxImageHandler* FindHandler(wxBitmapType imageType);
/**
Finds the handler associated with the given MIME type.
@param mimetype
MIME type.
@return A pointer to the handler if found, @NULL otherwise.
@see wxImageHandler
*/
static wxImageHandler* FindHandlerMime(const wxString& mimetype);
/**
Returns the static list of image format handlers.
@see wxImageHandler
*/
static wxList& GetHandlers();
/**
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 wxImageHandler, wxInitAllImageHandlers(), wxQuantize
*/
static void InitStandardHandlers();
/**
Adds a handler at the start of the static list of format handlers.
@param handler
A new image format handler object. There is usually only one instance
of a given handler class in an application session.
@see wxImageHandler
*/
static void InsertHandler(wxImageHandler* handler);
/**
Finds the handler with the given name, and removes it.
The handler is not deleted.
@param name
The handler name.
@return @true if the handler was found and removed, @false otherwise.
@see wxImageHandler
*/
static bool RemoveHandler(const wxString& name);
//@}
/**
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.
*/
static bool CanRead(const wxString& filename);
/**
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.
*/
static bool CanRead(wxInputStream& stream);
//@{
/**
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 @a filename, that's the name
of the file to query.
For the overload taking the parameter @a stream, that's the opened input
stream with image data.
See wxImageHandler::GetImageCount() for more info.
The parameter @a type may be one of the following values:
@li wxBITMAP_TYPE_BMP: Load a Windows bitmap file.
@li wxBITMAP_TYPE_GIF: Load a GIF bitmap file.
@li wxBITMAP_TYPE_JPEG: Load a JPEG bitmap file.
@li wxBITMAP_TYPE_PNG: Load a PNG bitmap file.
@li wxBITMAP_TYPE_PCX: Load a PCX bitmap file.
@li wxBITMAP_TYPE_PNM: Load a PNM bitmap file.
@li wxBITMAP_TYPE_TIF: Load a TIFF bitmap file.
@li wxBITMAP_TYPE_TGA: Load a TGA bitmap file.
@li wxBITMAP_TYPE_XPM: Load a XPM bitmap file.
@li wxBITMAP_TYPE_ICO: Load a Windows icon file (ICO).
@li wxBITMAP_TYPE_CUR: Load a Windows cursor file (CUR).
@li wxBITMAP_TYPE_ANI: Load a Windows animated cursor file (ANI).
@li wxBITMAP_TYPE_ANY: Will try to autodetect the format.
@return 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).
*/
static int GetImageCount(const wxString& filename,
wxBitmapType type = wxBITMAP_TYPE_ANY);
static int GetImageCount(wxInputStream& stream,
wxBitmapType type = wxBITMAP_TYPE_ANY);
//@}
/**
Iterates all registered wxImageHandler objects, and returns a string containing
file extension masks suitable for passing to file open/save dialog boxes.
@return The format of the returned string is @c "(*.ext1;*.ext2)|*.ext1;*.ext2".
It is usually a good idea to prepend a description before passing
the result to the dialog.
Example:
@code
wxFileDialog FileDlg( this, "Choose Image", ::wxGetCwd(), "",
_("Image Files ") + wxImage::GetImageExtWildcard(),
wxFD_OPEN );
@endcode
@see wxImageHandler
*/
static wxString GetImageExtWildcard();
/**
Converts a color in RGB color space to HSV color space.
*/
static wxImage::HSVValue RGBtoHSV(const wxImage::RGBValue& rgb);
/**
Converts a color in HSV color space to RGB color space.
*/
static wxImage::RGBValue HSVtoRGB(const wxImage::HSVValue& hsv);
};
/**
An instance of an empty image without an alpha channel.
*/
wxImage wxNullImage;
// ============================================================================
// Global functions/macros
// ============================================================================
/** @addtogroup group_funcmacro_appinitterm */
//@{
/**
Initializes all available image handlers. For a list of available handlers,
see wxImage.
If you don't need/want all image handlers loaded
@see wxImage, wxImageHandler
@header{wx/image.h}
*/
void wxInitAllImageHandlers();
//@}
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