RGB

Computes a valid color value for hi/truecolor modes

Syntax
   #define RGB(r,g,b) CULng((CUByte(r) Shl 16) Or (CUByte(g) Shl 8) Or 
   CUByte(b) Or (&hFF000000ul))

Usage
   result = RGB(red, green, blue)

Parameters
   red
      red color component value
   green
      green color component value
   blue
      blue color component value

Return Value
   The combined color.

Description
   red, green and blue are components ranging 0-255.

   The RGB function can be used to compute a valid color value for use 
   while in hi/truecolor modes. It returns an unsigned long, in the format 
   &hAARRGGBB, where RR, GG and BB equal the values passed to this 
   function, in hexadecimal format. AA is the implicit alpha value and is 
   automatically set to &hFF (opaque).
   It is possible to retrieve the red, green, blue and alpha values from a 
   color value, by using a combination of And and Shr.  The second example 
   below shows how to #define and use macros to do this.

   Note for Windows API programmers: The macro named RGB in the Windows 
   references has been renamed BGR in the FB headers for Windows to avoid 
   collisions. 

Example
   See Put (Graphics) example in addition.

   ScreenRes 640,480,32  '32 bit color
   Line(0,0)-(319,479), RGB(255,0,0) 'draws a bright red box on the left side of the window
   Line(639,0)-(320,479), RGB(0,0,255) 'draws a bright blue box on the right side of the window

   Sleep 'wait before exiting
      

   '' setting and retrieving Red, Green, Blue and Alpha values

   #define RGBA_R( c ) ( CULng( c ) Shr 16 And 255 )
   #define RGBA_G( c ) ( CULng( c ) Shr  8 And 255 )
   #define RGBA_B( c ) ( CULng( c )        And 255 )
   #define RGBA_A( c ) ( CULng( c ) Shr 24         )

   Dim As UByte r, g, b, a

   Dim As ULong col = RGB(128, 192, 64)

   Print Using "Color: _&H\      \"; Hex(col, 8)

   r = RGBA_R( col )
   g = RGBA_G( col )
   b = RGBA_B( col )
   a = RGBA_A( col )

   Print
   Print Using "Red:         _&H\\ = ###"; Hex(r, 2); r
   Print Using "Green:       _&H\\ = ###"; Hex(g, 2); g
   Print Using "Blue:        _&H\\ = ###"; Hex(b, 2); b
   Print Using "Alpha:       _&H\\ = ###"; Hex(a, 2); a
      

Version
   * Before fbc 1.08.0:
         Syntax:
            #define RGB(r,g,b) ((CULng(r) Shl 16) Or (CULng(g) Shl 8) Or 
            CULng(b) Or &hFF000000)
         RGB function returned an unsigned integer.

Dialect Differences
   * Not available in the -lang qb dialect unless referenced with the 
     alias __Rgb.

Differences from QB
   * New to FreeBASIC

See also
   * RGBA
   * Color
   * #define

   

   
