TColorRef (type) (WinTypes unit)


  TColorRef (type)     (WinTypes unit)


  TColorRef = Longint;


TColorRef is a 32-bit value corresponding to a color, used by numerous GDI functions. It can be interpreted in three different ways, depending on the value of the high-order byte of the high-order word in the long integer.

 - If that highest-order byte is zero, the next three bytes represent RGB
   color intensities  for blue, green, and red, respectively, so the value
   $00FF0000 represents full-intensity,  pure blue, $0000FF00 is pure green,
   and $000000FF is pure red.

   $00000000 is black, and $00FFFFFF is white.

   RGB values can most easily be converted into TColorRef values using the
   RGB  function.

 - If the highest-order byte is one, the next byte must be zero. The
   low-order word (the  next two bytes) form an index into a logical
   palette. Thus, $01000000 is index zero (the  first entry) of a palette.
   Integer-type palette indexes can be converted into TColorRef  values
   using the GetNearestPaletteIndex function.

 - If the highest-order byte is two, the next three bytes represent RGB
   color intensities (as  with RGB values described for a zero-highest
   byte), but the value will be matched to  the nearest color in the logical
   palette in the current device context. Palette-relative  RGB TColorRef
   values can be produced from RGB values with the  PaletteRGB function.

In order for palette index or palette-relative TColorRef values to work with a device context, an application with its own palette must select its palette into the device context being written to (using SelectPalette) and realize it (using RealizePalette) in order to have drawing functions use the correct colors from the palette. Similarly, before creating a logical drawing tool, the palette must be selected and realized if the colors are to take effect.

Тэги: TColorRef Types
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