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QB64-PE/internal/help/_RGBA.txt
2016-03-18 08:36:04 -03:00

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{{DISPLAYTITLE:_RGBA}}
The [[_RGBA]] function returns the closest palette index OR the 32 bit [[LONG]] color value in 32 bit screens.
{{PageSyntax}}
:colorindex~& = '''_RGBA('''{{Parameter|red}}, {{Parameter|green}}, {{Parameter|blue}}, {{Parameter|alpha}}[, {{Parameter|image_handle}}]''')'''
* 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 redulting color may lose the [[_BLUE]] value!''''
* {{Parameter|red&}} specifies the red component intensity from 0 to 255.
* {{Parameter|green&}} specifies the green component intensity from 0 to 255.
* {{Parameter|blue&}} specifies the blue component intensity from 0 to 255.
* 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.
* 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$]]([[MKL$]](colorvalue&), 3) to place 3 colors.
* If the ''image_handle'' is omitted the image is assumed to be the current [[_DEST|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!'''
''Example:'' Setting a font's background color alpha to clear to overlay a second text color.
{{CodeStart}} '' ''
scrn& = {{Cl|_NEWIMAGE}}(400, 400, 32)
{{Cl|SCREEN (statement)|SCREEN}} scrn&
fnt& = {{Cl|_LOADFONT}}("C:\WINDOWS\FONTS\ARIAL.TTF", 26)
{{Cl|_FONT}} fnt&
X% = 20
Y% = 20
{{Cl|COLOR}} {{Cl|_RGB}}(255, 255, 255), {{Cl|_RGB}}(0, 0, 0) 'Foreground set to WHITE background to BLACK
{{Cl|_PRINTSTRING}} (X%, Y%), "Hello World"
{{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|END}} '' ''
{{CodeEnd}}
{{small|Code by Unseen Machine}}
''Explanation:'' [[_PRINTSTRING]] allows text or font colors to be alpha blended in 32 bit screens.
{{PageSeeAlso}}
* [[_RGB]], [[_RGB32]], [[_RGBA32]]
* [[_RED]], [[_GREEN]], [[_BLUE]]
* [[_LOADIMAGE]]
* [[_PRINTSTRING]]
* [[HEX$ 32 Bit Values]], [[POINT]]
* [[SAVEIMAGE]] {{text|(bitmap creator)}}
* [http://www.w3schools.com/html/html_colornames.asp Hexadecimal Color Values]
{{PageNavigation}}