RGBA: Difference between revisions

From QB64 Phoenix Edition Wiki
Jump to navigation Jump to search
No edit summary
No edit summary
 
(4 intermediate revisions by the same user not shown)
Line 7: Line 7:




* The value returned is either the closest color attribute number or a 32-bit [[_UNSIGNED]] [[LONG]] color value.  
* 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.'''
* '''Return variable types must be [[LONG]] or the resulting color may lose the [[_BLUE]] value.'''
* {{Parameter|red&}} specifies the red component intensity from 0 to 255.
* {{Parameter|red&}} specifies the red component intensity from 0 to 255.
Line 14: Line 14:
* The [[_ALPHA|''alpha&'']] value can be set to make the color transparent (0), opaque (255) or somewhere in between.
* The [[_ALPHA|''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.
* Parameter values outside of the 0 to 255 range are clipped.
* Returns [[LONG]] 32-bit hexadecimal values from '''&H00{{text|00|red}}{{text|00|green}}{{text|00|blue}}''' to '''&HFF{{text|FF|red}}{{text|FF|green}}{{text|FF|blue}}''' with varying [[_ALPHA]] transparency.
* Returns [[LONG]] 32-bit hexadecimal values from '''&H00{{Text|00|red}}{{Text|00|green}}{{Text|00|blue}}''' to '''&HFF{{Text|FF|red}}{{Text|FF|green}}{{Text|FF|blue}}''' with varying [[_ALPHA]] transparency.
* When [[LONG]] values are [[PUT]] to file, the ARGB values become BGRA. Use [[LEFT$]]([[MKL$]]({{Parameter|colorIndex~&}}), 3) to place 3 colors.
* When [[LONG]] values are [[PUT]] to file, the ARGB values become BGRA. Use [[LEFT$]]([[MKL$]]({{Parameter|colorIndex~&}}), 3) to place 3 colors.
* If {{Parameter|imageHandle&}} is omitted, the image is assumed to be the current [[_DEST|destination]] or [[SCREEN]] page.
* If {{Parameter|imageHandle&}} is omitted, the image is assumed to be the current [[_DEST|destination]] or [[SCREEN]] page.
Line 25: Line 25:
{{CodeStart}}
{{CodeStart}}
scrn& = {{Cl|_NEWIMAGE}}(400, 400, 32)
scrn& = {{Cl|_NEWIMAGE}}(400, 400, 32)
{{Cl|SCREEN (statement)|SCREEN}} scrn&
{{Cl|SCREEN}} scrn&
fnt& = {{Cl|_LOADFONT}}("C:\WINDOWS\FONTS\ARIAL.TTF", 26)
fnt& = {{Cl|_LOADFONT}}("C:\WINDOWS\FONTS\ARIAL.TTF", 26)
{{Cl|_FONT}} fnt&
{{Cl|_FONT}} fnt&
Line 34: Line 34:
{{Cl|COLOR}} {{Cl|_RGB}}(255, 0, 0), {{Cl|_RGBA}}(0, 0, 0, 0) 'Foreground set to RED background to TRANSPARENT BLACK
{{Cl|COLOR}} {{Cl|_RGB}}(255, 0, 0), {{Cl|_RGBA}}(0, 0, 0, 0) 'Foreground set to RED background to TRANSPARENT BLACK
{{Cl|_PRINTSTRING}} (X% + 2, Y% + 2), "Hello World"
{{Cl|_PRINTSTRING}} (X% + 2, Y% + 2), "Hello World"
{{Cl|END}}  
{{Cl|END}}
{{CodeEnd}}
{{CodeEnd}}
{{small|Code by Unseen Machine}}
{{Small|Code by Unseen Machine}}
''Explanation:'' [[_PRINTSTRING]] allows text or font colors to be alpha blended in 32 bit screens.
''Explanation:'' [[_PRINTSTRING]] allows text or font colors to be alpha blended in 32 bit screens.


Line 46: Line 46:
* [[_PRINTSTRING]]
* [[_PRINTSTRING]]
* [[HEX$ 32 Bit Values]], [[POINT]]
* [[HEX$ 32 Bit Values]], [[POINT]]
* [[SAVEIMAGE]]
* [[SaveImage SUB]]
* [http://www.w3schools.com/html/html_colornames.asp Hexadecimal Color Values]
* [http://www.w3schools.com/html/html_colornames.asp Hexadecimal Color Values]




{{PageNavigation}}
{{PageNavigation}}
[[Category:Latest]]

Latest revision as of 20:04, 5 January 2024

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


Navigation:
Main Page with Articles and Tutorials
Keyword Reference - Alphabetical
Keyword Reference - By usage
Report a broken link
Retrieved from "https://qb64phoenix.com/qb64wiki/index.php?title=RGBA&oldid=8670"