The _RGBA function returns the closest palette index (legacy SCREEN modes) OR the 32-bit LONG color value (32-bit screens).
Syntax
colorIndex~& = _RGBA(red&, green&, blue&, alpha&[, imageHandle&])
- The value returned is either the closest color attribute number or a 32-bit _UNSIGNED LONG color value.
- Return variable types must be LONG or the resulting color may lose the _BLUE value.
- red& specifies the red component intensity from 0 to 255.
- green& specifies the green component intensity from 0 to 255.
- blue& specifies the blue component intensity from 0 to 255.
- The _ALPHA value can be set to make the color transparent (0), opaque (255) or somewhere in between.
- Parameter values outside of the 0 to 255 range are clipped.
- Returns LONG 32-bit hexadecimal values from &H00000000 to &HFFFFFFFF with varying _ALPHA transparency.
- When LONG values are PUT to file, the ARGB values become BGRA. Use LEFT$(MKL$(colorIndex~&), 3) to place 3 colors.
- If imageHandle& is omitted, the image is assumed to be the current _DEST or SCREEN page.
- Allows the blending of pixel colors red, green and blue to create any of 16 million colors.
- NOTE: Default 32-bit backgrounds are clear black or _RGBA(0, 0, 0, 0). Use CLS to make the black opaque.
Example(s)
Setting a font’s background color alpha to clear to overlay a second text color.
scrn& = _NEWIMAGE(400, 400, 32)
SCREEN scrn&
fnt& = _LOADFONT("C:\WINDOWS\FONTS\ARIAL.TTF", 26)
_FONT fnt&
X% = 20
Y% = 20
COLOR _RGB(255, 255, 255), _RGB(0, 0, 0) 'Foreground set to WHITE background to BLACK
_PRINTSTRING (X%, Y%), "Hello World"
COLOR _RGB(255, 0, 0), _RGBA(0, 0, 0, 0) 'Foreground set to RED background to TRANSPARENT BLACK
_PRINTSTRING (X% + 2, Y% + 2), "Hello World"
END
Explanation: _PRINTSTRING allows text or font colors to be alpha blended in 32 bit screens.