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　　Gets a pixel value at a specified position in a GdkImage.

　　image : a GdkImage.

　　x : the x coordinate of the pixel to get.

　　y : the y coordinate of the pixel to get.

　　Returns : the pixel value at the given position.

　　See Also

　　Bitmaps and Pixmaps

　　Graphics which are stored on the X Windows server. Since these are stored on the server they can be drawn very quickly, and all of the Drawing Primitives can be used to draw on them. Their main disadvantage is that manipulating individual pixels can be very slow.

　　GdkRGB

　　Built on top of GdkImage, this provides much more functionality, including the dithering of colors to produce better output on low-color displays.

　　Colormaps and Colors

　　Name

　　Colormaps and Colors -- manipulation of colors and colormaps.

　　Synopsis

#include <gdk/gdk.h>
structGdkColor;
structGdkColormap;
GdkColormap* gdk_colormap_new (GdkVisual *visual,gint allocate);
GdkColormap* gdk_colormap_ref (GdkColormap *cmap);
voidgdk_colormap_unref(GdkColormap *cmap);
GdkColormap* gdk_colormap_get_system(void);
gintgdk_colormap_get_system_size(void);
voidgdk_colormap_change (GdkColormap *colormap,gint ncolors);
gintgdk_colormap_alloc_colors (GdkColormap *colormap,GdkColor *colors,
gint ncolors,gboolean writeable,gboolean best_match,gboolean *success);
gbooleangdk_colormap_alloc_color(GdkColormap *colormap,GdkColor *color,
gboolean writeable,gboolean best_match);
voidgdk_colormap_free_colors(GdkColormap *colormap,
GdkColor *colors,gint ncolors);
GdkVisual*gdk_colormap_get_visual (GdkColormap *colormap);
voidgdk_colors_store(GdkColormap *colormap,GdkColor *colors,gint ncolors);
GdkColor* gdk_color_copy(GdkColor *color);
voidgdk_color_free(GdkColor *color);
gbooleangdk_colors_alloc(GdkColormap *colormap,
gint contiguous,gulong *planes,gint nplanes,gulong *pixels,gint npixels);
voidgdk_colors_free (GdkColormap *colormap,
gulong *pixels,gint npixels,gulong planes);
gbooleangdk_color_white (GdkColormap *colormap,GdkColor *color);
gbooleangdk_color_black (GdkColormap *colormap,GdkColor *color);
gbooleangdk_color_parse (const gchar *spec,GdkColor *color);
gbooleangdk_color_alloc (GdkColormap *colormap,GdkColor *color);
gbooleangdk_color_change(GdkColormap *colormap,GdkColor *color);
gintgdk_color_equal (const GdkColor *colora,const GdkColor *colorb);
guint gdk_color_hash(const GdkColor *colora,const GdkColor *colorb); 

　　Description

　　These functions are used to modify colormaps. A colormap is an object that contains the mapping between the color values stored in memory and the RGB values that are used to display color values. In general, colormaps only contain significant information for pseudo-color visuals, but even for other visual types, a colormap object is required in some circumstances.

　　There are a couple of special colormaps that can be retrieved. The system colormap (retrieved with gdk_colormap_get_system()) is the default colormap of the system. If you are using GdkRGB, there is another colormap that is important - the colormap in which GdkRGB works, retrieved with gdk_rgb_get_cmap(). However, when using GdkRGB, it is not generally necessary to allocate colors directly.

　　In previous revisions of this interface, a number of functions that take a GdkColormap parameter were replaced with functions whose names began with "gdk_colormap_". This process will probably be extended somewhat in the future - gdk_color_white(), gdk_color_black(), and gdk_color_change() will probably become aliases.

　　Details

　　struct GdkColor

struct GdkColor
{
gulongpixel;
gushort red;
gushort green;
gushort blue;
}; 

　　The GdkColor structure is used to describe an allocated or unallocated color.

　　pixel For allocated colors, the value used to draw this color on the screen.

　　red The red component of the color. This is a value between 0 and 65535, with 65535 indicating full intensitiy.

　　green the blue component of the color.

　　blue the green component of the color..

　　struct GdkColormap

struct GdkColormap
{
gintsize;
GdkColor *colors;
}; 

　　The colormap structure contains the following public fields.

　　size For pseudo-color colormaps, the number of colors in the colormap..

　　colors An array containing the current values in the colormap. This can be used to map from pixel values back to RGB values. This is only meaningful for pseudo-color colormaps.