forked from AuroraMiddleware/gtk
50ab749f4b
2000-02-02 Damon Chaplin <damon@karuna.freeserve.co.uk>
* gdk/tmpl/*.sgml: ran make templates.
* gdk/gdk-docs.sgml: rearranged sections.
* gdk/tmpl/events.sgml: documented.
* gdk/tmpl/general.sgml: documented.
* gdk/tmpl/rgb.sgml: fixed a few '@' -> '#'.
* gdk/gdk-sections.txt: rearranged a few bits, including moving
GdkWChar and related functions from the input method section to the
font section, and GdkCapStyle etc. from Drawing Primitives to GCs.
* gdk/tmpl/images.sgml: documented.
* gdk/tmpl/drawing.sgml: updated.
* gdk/tmpl/regions.sgml: updated.
* gdk/tmpl/input_contexts.sgml: documented.
* gdk/tmpl/input_methods.sgml: documented.
* gdk/tmpl/selections.sgml: changed xref to a link since Jade says
a xref to a RefEntry is not supported.
157 lines
4.8 KiB
Plaintext
157 lines
4.8 KiB
Plaintext
<!-- ##### SECTION Title ##### -->
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Images
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<!-- ##### SECTION Short_Description ##### -->
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an area for bit-mapped graphics stored on the X Windows client.
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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The #GdkImage type represents an area for drawing graphics.
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It has now been superceded to a large extent by the much more flexible
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<link linkend="gdk-GdkRGB">GdkRGB</link> functions.
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</para>
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<para>
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To create an empty #GdkImage use gdk_image_new().
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To create a #GdkImage from bitmap data use gdk_image_new_bitmap().
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To create an image from part of a #GdkWindow use gdk_image_get().
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</para>
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<para>
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The image can be manipulated with gdk_image_get_pixel() and
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gdk_image_put_pixel(), or alternatively by changing the actual pixel data.
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Though manipulating the pixel data requires complicated code to cope with
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the different formats that may be used.
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</para>
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<para>
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To draw a #GdkImage in a #GdkWindow or #GdkPixmap use gdk_draw_image().
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</para>
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<para>
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To destroy a #GdkImage use gdk_image_destroy().
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</para>
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<!-- ##### SECTION See_Also ##### -->
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<para>
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<variablelist>
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<varlistentry>
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<term><link linkend="gdk-Bitmaps-and-Pixmaps">Bitmaps and Pixmaps</link></term>
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<listitem><para>
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Graphics which are stored on the X Windows server.
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Since these are stored on the server they can be drawn very quickly, and all
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of the <link linkend="gdk-Drawing-Primitives">Drawing Primitives</link> can be
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used to draw on them. Their main disadvantage is that manipulating individual
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pixels can be very slow.
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</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><link linkend="gdk-GdkRGB">GdkRGB</link></term>
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<listitem><para>
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Built on top of #GdkImage, this provides much more functionality,
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including the dithering of colors to produce better output on low-color
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displays.
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</para></listitem>
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</varlistentry>
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</variablelist>
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</para>
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<!-- ##### STRUCT GdkImage ##### -->
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<para>
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The #GdkImage struct contains information on the image and the pixel data.
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</para>
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@type: the type of the image.
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@visual: the visual.
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@byte_order: the byte order.
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@width: the width of the image in pixels.
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@height: the height of the image in pixels.
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@depth: the depth of the image, i.e. the number of bits per pixel.
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@bpp: the number of bytes per pixel.
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@bpl: the number of bytes per line of the image.
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@mem: the pixel data.
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<!-- ##### FUNCTION gdk_image_new ##### -->
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<para>
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Creates a new #GdkImage.
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</para>
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@type: the type of the #GdkImage, one of %GDK_IMAGE_NORMAL, %GDK_IMAGE_SHARED
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and %GDK_IMAGE_FASTEST. %GDK_IMAGE_FASTEST is probably the best choice, since
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it will try creating a %GDK_IMAGE_SHARED image first and if that fails it will
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then use %GDK_IMAGE_NORMAL.
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@visual: the #GdkVisual to use for the image.
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@width: the width of the image in pixels.
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@height: the height of the image in pixels.
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@Returns: a new #GdkImage, or NULL if the image could not be created.
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<!-- ##### ENUM GdkImageType ##### -->
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<para>
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Specifies the type of a #GdkImage.
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</para>
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@GDK_IMAGE_NORMAL: The original X image type, which is quite slow since the
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image has to be transferred from the client to the server to display it.
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@GDK_IMAGE_SHARED: A faster image type, which uses shared memory to transfer
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the image data between client and server. However this will only be available
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if client and server are on the same machine and the shared memory extension
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is supported by the server.
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@GDK_IMAGE_FASTEST: Specifies that %GDK_IMAGE_SHARED should be tried first,
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and if that fails then %GDK_IMAGE_NORMAL will be used.
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<!-- ##### FUNCTION gdk_image_new_bitmap ##### -->
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<para>
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Creates a new #GdkImage with a depth of 1 from the given data.
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</para>
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@visual: the #GdkVisual to use for the image.
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@data: the pixel data.
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@width: the width of the image in pixels.
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@height: the height of the image in pixels.
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@Returns: a new #GdkImage.
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<!-- ##### FUNCTION gdk_image_get ##### -->
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<para>
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Gets part of a #GdkWindow and stores it in a new #GdkImage.
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</para>
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@window: the #GdkWindow to copy from.
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@x: the left edge of the rectangle to copy from @window.
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@y: the top edge of the rectangle to copy from @window.
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@width: the width of the area to copy, in pixels.
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@height: the height of the area to copy, in pixels.
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@Returns: a new #GdkImage with a copy of the given area of @window.
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<!-- ##### FUNCTION gdk_image_destroy ##### -->
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<para>
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Destroys a #GdkImage, freeing any resources allocated for it.
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</para>
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@image: a #GdkImage.
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<!-- ##### FUNCTION gdk_image_put_pixel ##### -->
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<para>
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Sets a pixel in a #GdkImage to a given pixel value.
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</para>
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@image: a #GdkImage.
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@x: the x coordinate of the pixel to set.
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@y: the y coordinate of the pixel to set.
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@pixel: the pixel value to set.
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<!-- ##### FUNCTION gdk_image_get_pixel ##### -->
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<para>
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Gets a pixel value at a specified position in a #GdkImage.
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</para>
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@image: a #GdkImage.
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@x: the x coordinate of the pixel to get.
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@y: the y coordinate of the pixel to get.
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@Returns: the pixel value at the given position.
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