_RGBA32 - mkilgore/QB64pe GitHub Wiki

The _RGBA32 function returns the 32-bit RGBA color value with the specified red, green, blue and alpha component intensities.

color32value~& = _RGBA32(red&, green&, blue&, alpha&)

• The value returned is a 32-bit _UNSIGNED LONG color value.
• Return variable types must be _UNSIGNED LONG or 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.
• alpha& specifies the ''alpha'' component transparency value from 0 (fully transparent) to 255 (opaque).
• Alpha or intensity values outside of the valid range of 0 to 255 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$(MKL$(color32value~&), 3) to place 3 colors.
• NOTE: Default 32-bit backgrounds are clear black or _RGBA(0, 0, 0, 0). Use CLS to make the black opaque.

Example: Changing the ALPHA value to fade an image in and out using a 32 bit PNG image.

img& = _LOADIMAGE("qb64_trans.png")  'use any 24/32 bit image
'Turn off auto display
_DISPLAY

' Fade in
FOR...NEXT i% = 255 TO 0 STEP -5
  _LIMIT 20                          'control fade speed 
  _PUTIMAGE (0, 0)-(600, 400), img&
  LINE (0, 0)-(600, 400), _RGBA(0, 0, 0, i%), BF 'decrease black box transparency
  _DISPLAY
NEXT

' Fade out
FOR...NEXT i% = 0 TO 255 STEP 5
  _LIMIT 20                          'control fade speed 
  _PUTIMAGE (0, 0)-(600, 400), img&
  LINE (0, 0)-(600, 400), _RGBA(0, 0, 0, i%), BF 'increase black box transparency
  _DISPLAY
NEXT
END '' ''

• _RGB32, _RGBA, _RGB
• _RED32, _GREEN32, _BLUE32
• HEX$ 32 Bit Values, POINT
• SAVEIMAGE
• Hexadecimal Color Values