The function obtains the RGB value for the pixel value in the pixel member of the specified structure and then converts the value to the target format as specified by the result_format argument. If the pixel is not a valid index in the specified colormap, a error results. The function obtains the RGB values for pixel values in the pixel members of structures and then converts the values to the target format as specified by the result_format argument. If a pixel is not a valid index into the specified colormap, a error results. If more than one pixel is in error, the one that gets reported is arbitrary.
and can generate and errors.
The function looks up the string name of a color with respect to the screen associated with the specified colormap. It returns both the exact color values and the closest values provided by the screen with respect to the visual type of the specified colormap. The values are returned in the format specified by result_format. If the color name is not in the Host Portable Character Encoding, the result is implementation-dependent. Use of uppercase or lowercase does not matter. returns or if the name is resolved; otherwise, it returns If is returned, the color specification returned in color_screen_return is the result of gamut compression.