Graphics Function: Returns the current background Red-Green-Blue (RGB) color value for both text and graphics.
The result type is INTEGER(4). The result is the RGB value of the current background color for both text and graphics.
In each RGB color value, each of the three colors, red, green, and blue, is represented by an eight-bit value (2 hex digits). In the value you retrieve with GETBKCOLORRGB, red is the rightmost byte, followed by green and blue. The RGB value's internal structure is as follows:
Larger numbers correspond to stronger color intensity with binary 1111111 (hex FF) the maximum for each of the three components. For example, Z'0000FF' yields full-intensity red, Z'00FF00' full-intensity green, Z'FF0000' full-intensity blue, and Z'FFFFFF' full-intensity for all three, resulting in bright white.
GETBKCOLORRGB returns the RGB color value of the current background for both text and graphics, set with SETBKCOLORRGB. The RGB color value of text over the background color (used by text functions such as OUTTEXT, WRITE, and PRINT) is set with SETTEXTCOLORRGB and returned with GETTEXTCOLORRGB. The RGB color value of graphics over the background color (used by graphics functions such as ARC, OUTGTEXT, and FLOODFILLRGB) is set with SETCOLORRGB and returned with GETCOLORRGB.
SETBKCOLORRGB (and the other RGB color selection functions SETCOLORRGB and SETTEXTCOLORRGB) sets the color to a value chosen from the entire available range. The non-RGB color functions (SETBKCOLOR, SETCOLOR, and SETTEXTCOLOR) use color indexes rather than true color values. If you use color indexes, you are restricted to the colors available in the palette, at most 256. Some display adapters (SVGA and true color) are capable of creating 262,144 (256K) colors or more. To access any available color, you need to specify an explicit RGB value with an RGB color function, rather than a palette index with a non-RGB color function.
! Build as a QuickWin or Standard Graphics App.
INTEGER(4) back, fore, oldcolor
INTEGER(2) status, x1, y1, x2, y2
x1 = 80; y1 = 50
x2 = 240; y2 = 150
oldcolor = SETCOLORRGB(Z'FF') ! red
! reverse the screen
back = GETBKCOLORRGB()
fore = GETCOLORRGB()
oldcolor = SETBKCOLORRGB(fore)
oldcolor = SETCOLORRGB(back)
CALL CLEARSCREEN ($GCLEARSCREEN)
status = ELLIPSE($GBORDER, x1, y1, x2, y2)