FindColor

Find the closest matching color in a ColorMap. (V39)

cm

colormap

R

red level (32 bit left justified fraction)

G

green level (32 bit left justified fraction)

B

blue level (32 bit left justified fraction)

MaxPen

the maximum entry in the color table to search. A value of -1 will limit the search to only those pens which could be rendered in (for instance, it will not examine the sprite colors on a 4 color screen).

The system will attempt to find the color in the passed ColorMap which most closely matches the RGB values passed. No new pens will be allocated, and you should not ReleasePen() the returned pen.

This function is not sensitive to palette sharing issues. Its intended use is for:

• programs which pop up on public screens when those screens are not using palette sharing. You might use this function as a fallback when ObtainBestPenA() says that there are no sharable pens.
  
  
• Internal color matching by an application which is either running on a non-public screen, or which wants to match colors to an internal color table which may not be associated with any displayed screen.
  
  

In order to use the MaxPen=-1 feature, you must have initialized palette sharing via AttachPalExtra() (all intuition screens do this). Otherwise, MaxPen=-1 will search all colors in the colormap.

When searching for the color which most closely matches the RGB values passed, the graphics.library default color match function will be used. You cannot override this function and you cannot influence how it will perform the matching operation.

The default color match function in graphics.library V39-V47 pays no attention to how close two colors are in terms human perception because it lends greatest weight to the largest relative difference in any two random RGB components. This will impact fidelity and will randomly consider two colors to "match most closely" which may have little else in common.

This has been addressed in version 47.9 of graphics library

ObtainBestPenA(), GetColorMap(), ObtainPen(), ReleasePen()