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 NAME     
 |  |  |  | RGB, readcolmap, writecolmap – access display color map 
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 SYNOPSIS     
 |  |  |  | #include <u.h> #include <libc.h>
 #include <draw.h> 
    
    
    
    
    
    
    
    
    int    readcolmap(Display *d, RGB *map) 
    
    
    int    writecolmap(Display *d, RGB *map)
 
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 DESCRIPTION     
 |  |  |  | Colors are described by their red, green, and blue light intensities,
    in an RGB datum: 
 Black is represented by zero in all three positions and white
    has the maximum unsigned long value in all three positions. 
    
    
    A color map is an array of RGBs, of length 2depth, giving the
    colors for pixels 0, 1, 2, etc. On displays with color mapped
    pixels (typically 8-bit displays), one retrieves RGB color information
    by treating the pixel data as an offset into the color map. 
    
    
    Readcolmap reads the color map for the given display into the
    provided map, which must have enough space to hold it. Writecolmap
    associates the given color map with the given display, if possible.
    (The hardware might not allow this.) Both return 0 on success,
    or –1 on error, setting errstr. 
    
    
    Changing the hardware color map does not change the color map
    used by the draw(3) operator to convert between mapped and true
    color or greyscale images, which is described in color(7).|  |  |  | typedef struct RGB {
 
 } RGB;|  |  |  | ulong red; ulong green;
 ulong blue;
 
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 SOURCE     
 SEE ALSO     
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