RGBA

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 destination 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.

Examples

Example: 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

Code by Unseen Machine

Explanation: _PRINTSTRING allows text or font colors to be alpha blended in 32 bit screens.

See also

• _RGB, _RGB32, _RGBA32
• _RED, _GREEN, _BLUE
• _LOADIMAGE
• _PRINTSTRING
• HEX$ 32 Bit Values, POINT
• SaveImage SUB
• Hexadecimal Color Values

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