_RGBA32 - QB64Official/qb64 GitHub Wiki

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

Syntax

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

Description

  • 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(s)

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


SCREEN _NEWIMAGE(600, 400, 32)

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

' Fade in
FOR 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 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 

See Also