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