/// Highest quality but slowest execution time.
wxIMAGE_QUALITY_BICUBIC,
- /// Default image resizing algorithm used by wxImage::Scale().
+ /**
+ Use surrounding pixels to calculate an average that will be used for
+ new pixels. This method is typically used when reducing the size of
+ an image.
+ */
+ wxIMAGE_QUALITY_BOX_AVERAGE,
+
+ /**
+ Default image resizing algorithm used by wxImage::Scale(). Currently
+ the same as wxIMAGE_QUALITY_NEAREST.
+ */
wxIMAGE_QUALITY_NORMAL,
- /// Best image resizing algorithm, currently same as wxIMAGE_QUALITY_BICUBIC.
+ /**
+ Best image resizing algorithm. Since version 2.9.2 this results in
+ wxIMAGE_QUALITY_BOX_AVERAGE being used when reducing the size of the
+ image (meaning that both the new width and height will be smaller than
+ the original size). Otherwise wxIMAGE_QUALITY_BICUBIC is used.
+ */
wxIMAGE_QUALITY_HIGH
};
{
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.
+ wxPNG_TYPE_GREY_RED = 3, ///< Greyscale PNG image using red as grey.
+ wxPNG_TYPE_PALETTE = 4 ///< Palette encoding.
};
/**
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.
+ channel with wxImage::HasAlpha. Currently the BMP, PNG, 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 or TGA format to avoid losing it as these are the only handlers
+ that currently support saving with alpha.
@section image_handlers Available image handlers
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.
+ - wxBMPHandler: For loading (including alpha support) and saving, always installed.
+ - wxPNGHandler: For loading and saving. Includes alpha support.
- wxJPEGHandler: For loading and saving.
- - wxGIFHandler: Only for loading, due to legal issues.
+ - 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.
- - wxTGAHandler: For loading only.
+ - wxTIFFHandler: For loading (including alpha support) and saving.
+ - wxTGAHandler: For loading and saving. Includes alpha support.
- wxIFFHandler: For loading only.
- wxXPMHandler: For loading and saving.
- wxICOHandler: For loading and saving.
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{gdi}
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.
+ Use HasOption() if 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
the resulting PNG file. Use this option if your application produces
images with small size variation.
+ Options specific to wxGIFHandler:
+ @li @c 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.
+
@param name
The name of the option, case-insensitive.
@return
/**
Register an image handler.
- See @ref image_handlers for a list of the available handlers.
+
+ Typical example of use:
+ @code
+ wxImage::AddHandler(new wxPNGHandler);
+ @endcode
+
+ See @ref 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.
+
+ @param handler
+ A heap-allocated handler object which will be deleted by wxImage
+ if it is removed later by RemoveHandler() or at program shutdown.
*/
static void AddHandler(wxImageHandler* handler);
/**
Finds the handler with the given name, and removes it.
- The handler is not deleted.
+
+ The handler is also deleted.
@param name
The handler name.
//@{
/**
- Initializes all available image handlers. For a list of available handlers,
- see wxImage.
- If you don't need/want all image handlers loaded
+ Initializes all available image handlers.
+
+ This function calls wxImage::AddHandler() for all the available image
+ handlers (see @ref image_handlers for the full list). Calling it is the
+ simplest way to initialize wxImage but it creates and registers even the
+ handlers your program may not use. If you want to avoid the overhead of
+ doing this you need to call wxImage::AddHandler() manually just for the
+ handlers that you do want to use.
@see wxImage, wxImageHandler
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