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29 lines
1.4 KiB
Plaintext
29 lines
1.4 KiB
Plaintext
The {{KW|_RED}} function returns the palette index OR the red component intensity of a 32-bit screen only.
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{{PageSyntax}}
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:{{Parameter|result&}} = {{KW|_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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* 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 {{KW|_RGB}}, {{KW|_RGBA}}, {{KW|_RGB32}} or {{KW|_RGBA32}} funtions.
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* An image handle is optional.
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''See Example:'' [[POINT]]
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{{PageSeeAlso}}
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* {{KW|_GREEN}}, {{KW|_BLUE}}
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* {{KW|_RGB}}, {{KW|RGB32}}
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* {{KW|_LOADIMAGE}} <!-- why have this link ? -->
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{{PageNavigation}} |