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

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{{DISPLAYTITLE:_RED}}
The [[_RED]] function returns the palette index or the red component intensity of a 32-bit image color.
{{PageSyntax}}
:: redintensity& = '''_RED('''{{Parameter|rgbaColorIndex&}}[, {{Parameter|imageHandle&}}]''')'''
{{PageDescription}}
* {{Parameter|rgbaColorIndex&}} is the ''RGBA'' color value or palette index of the color to retrieve the red component intensity from.
* The [[LONG]] intensity value returned ranges from 0 (no intensity, not present) to 255 (full intensity).
* If {{Parameter|imageHandle&}} specifies a 32-bit color image, {{Parameter|rgbaColorIndex&}} is interpreted as a 32-bit ''RGBA'' color value.
* If {{Parameter|imageHandle&}} specifies an image that uses a palette, {{Parameter|rgbaColorIndex&}} is interpreted as a palette index.
* If {{Parameter|imageHandle&}} is not specified, it is assumed to be the current write page.
* If {{Parameter|imageHandle&}} is an invalid handle, an [[ERROR Codes|invalid handle]] error occurs.
* If {{Parameter|rgbaColorIndex&}} is outside the range of valid indexes for a given image mode, an [[ERROR Codes|illegal function call]] error occurs.
* Uses index parameters passed by the {{KW|_RGB}}, {{KW|_RGBA}}, {{KW|_RGB32}} or {{KW|_RGBA32}} funtions.
* An image handle is optional.
''See Example:''
* [[POINT]]
{{PageSeeAlso}}
* [[_GREEN]], [[_BLUE]]
* [[_RGB]], [[RGB32]]
* [[_LOADIMAGE]]
{{PageNavigation}}