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58 lines
2.7 KiB
Text
58 lines
2.7 KiB
Text
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The {{KW|_RGBA32}} function ALWAYS returns the 32-bit ''RGBA'' color value with specified red, green, blue and alpha component intensities.
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{{PageSyntax}}
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:{{Parameter|result~&}} = [[_RGBA32]]'''({{Parameter|red&}}, {{Parameter|green&}}, {{Parameter|blue&}}, {{Parameter|alpha&}})'''
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{{PageDescription}}
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* The value returned is ALWAYS a 32 bit [[_UNSIGNED]] [[LONG]] color value.
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* '''Return variable types MUST be [[LONG]] or you may lose the [[_BLUE]] value!'''
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* {{Parameter|red&}} specifies the red component intensity from 0 to 255.
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* {{Parameter|green&}} specifies the green component intensity from 0 to 255.
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* {{Parameter|blue&}} specifies the blue component intensity from 0 to 255.
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* {{Parameter|alpha&}} specifies the [[_ALPHA|''alpha'']] component transparency value from 0 (fully transparent) to 255 (opaque).
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* Alpha or intensity values outside of the valid range of 0 to 255 are clipped.
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* 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.
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* When [[LONG]] values are [[PUT]] to file, the ARGB values become BGRA. Use [[LEFT$]]([[MKL$]](colorvalue&), 3) to place 3 colors.
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* '''NOTE: Default 32 bit backgrounds are clear black or [[_RGBA]](0, 0, 0, 0)! Use [[CLS]] to make the black opaque!'''
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''Example:'' Changing the [[ALPHA]] value to fade an image in and out using a 32 bit PNG image!
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{{CodeStart}} '' ''
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{{Cl|SCREEN (statement)|SCREEN}} {{Cl|_NEWIMAGE}}(600, 400, 32)
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img& = {{Cl|_LOADIMAGE}}("qb64.png") 'use any 24/32 bit image
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'//Turn off auto display
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{{Cl|_DISPLAY}}
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' Fade in
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{{Cl|FOR...NEXT|FOR}} i% = 255 {{Cl|TO}} 0 {{Cl|STEP}} -5
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{{Cl|_LIMIT}} 20 'control fade speed
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{{Cl|_PUTIMAGE}} (0, 0)-(600, 400), img&
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{{Cl|LINE}} (0, 0)-(600, 400), {{Cl|_RGBA}}(0, 0, 0, i%), BF 'increase black box transparency
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{{Cl|_DISPLAY}}
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{{Cl|NEXT}}
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' Fade out
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{{Cl|FOR...NEXT|FOR}} i% = 0 {{Cl|TO}} 255 {{Cl|STEP}} 5
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{{Cl|_LIMIT}} 20 'control fade speed
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{{Cl|_PUTIMAGE}} (0, 0)-(600, 400), img&
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{{Cl|LINE}} (0, 0)-(600, 400), {{Cl|_RGBA}}(0, 0, 0, i%), BF 'decrease black box transparency
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{{Cl|_DISPLAY}}
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{{Cl|NEXT}}
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{{Cl|END}} '' ''
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{{CodeEnd}}
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{{small|Code by Unseen Machine}}
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:''Note:'' The QB64.PNG bee image used is available at the top of the QB64 forum: http://www.qb64.net/forum/index.php
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{{PageSeeAlso}}
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* [[_RGB32]], [[_RGBA]], [[_RGB]]
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* [[_RED32]], [[_GREEN32]], [[_BLUE32]]
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* [[HEX$ 32 Bit Values]], [[POINT]]
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* [[SAVEIMAGE]] {{text|(bitmap creator)}}
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* [http://www.w3schools.com/html/html_colornames.asp Hexadecimal Color Values]
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{{PageNavigation}}
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