RGB


Computes a valid color value for hi/truecolor modes

Syntax:
#define RGB(r,g,b) ((cuint(r) shl 16) or (cuint(g) shl 8) or cuint(b) or &hFF000000)

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 integer 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.

Examples:
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 ) ( CUInt( c ) Shr 16 And 255 )
#define RGBA_G( c ) ( CUInt( c ) Shr  8 And 255 )
#define RGBA_B( c ) ( CUInt( c )        And 255 )
#define RGBA_A( c ) ( CUInt( c ) Shr 24         )

Dim As UInteger r, g, b, a

Dim As UInteger 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


Dialect Differences:
Differences from QB:
See also:
Back to 2D Drawing Functions




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