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71 lines
2.7 KiB
Markdown
71 lines
2.7 KiB
Markdown
The [_RGB](_RGB) function returns the closest palette attribute index (legacy SCREEN modes) OR the [LONG](LONG) 32-bit color value (32-bit screens).
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## Syntax
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> colorIndex~& = [_RGB](_RGB)(red&, green&, blue&[, imageHandle&])
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## Description
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* The value returned is either the closest color attribute number or a 32-bit [_UNSIGNED](_UNSIGNED) [LONG](LONG) color value.
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* **Return variable types must be [LONG](LONG) or resulting color may lose the [_BLUE](_BLUE) value.**
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* red& specifies the red component intensity from 0 to 255.
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* green& specifies the green component intensity from 0 to 255.
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* blue& specifies the blue component intensity from 0 to 255.
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* Intensity values outside the valid range are clipped.
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* Returns [LONG](LONG) 32-bit hexadecimal values from **&HFF000000** to **&HFFFFFFFF**, always with full [_ALPHA](_ALPHA).
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* When [LONG](LONG) values are [PUT](PUT) to file, the ARGB values become BGRA. Use [LEFT$](LEFT$)([MKL$](MKL$)(colorIndex~&), 3) to place 3 colors.
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* If the imageHandle& is omitted the image is assumed to be the current [_DEST](_DEST) or [SCREEN](SCREEN) page.
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* Colors returned are always opaque as the transparency value is always 255. Use [_ALPHA](_ALPHA) or [_CLEARCOLOR](_CLEARCOLOR) to change it.
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* **NOTE: Default 32-bit backgrounds are clear black or [_RGBA](_RGBA)(0, 0, 0, 0). Use [CLS](CLS) to make the black opaque.**
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## Example(s)
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Converting the color port RGB intensity palette values 0 to 63 to 32 bit hexadecimal values.
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```vb
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SCREEN 12
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DIM hex32$(15)
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FOR attribute = 1 TO 15
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OUT &H3C7, attribute 'set color attribute to read
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red = INP(&H3C9) * 4 'multiply by 4 to convert intensity to 0 to 255 RGB values
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grn = INP(&H3C9) * 4
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blu = INP(&H3C9) * 4
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hex32$(attribute) = "&H" + HEX$(_RGB32(red, grn, blu)) 'always returns the 32 bit value
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COLOR attribute
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PRINT "COLOR" + STR$(_RGB(red, grn, blu)) + " = " + hex32$(attribute) 'closest attribute
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NEXT
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```
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```text
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COLOR 1 = &HFF0000A8
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COLOR 2 = &HFF00A800
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COLOR 3 = &HFF00A8A8
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COLOR 4 = &HFFA80000
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COLOR 5 = &HFFA800A8
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COLOR 6 = &HFFA85400
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COLOR 7 = &HFFA8A8A8
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COLOR 8 = &HFF545454
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COLOR 9 = &HFF5454FC
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COLOR 10 = &HFF54FC54
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COLOR 11 = &HFF54FCFC
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COLOR 12 = &HFFFC5454
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COLOR 13 = &HFFFC54FC
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COLOR 14 = &HFFFCFC54
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COLOR 15 = &HFFFCFCFC
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```
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> *Note:* This procedure also shows how the returns from [_RGB](_RGB) and [_RGB32](_RGB32) differ in a non-32 bit screen mode.
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## See Also
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* [_RGBA](_RGBA), [_RGB32](_RGB32), [_RGBA32](_RGBA32)
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* [_RED](_RED), [_GREEN](_GREEN), [_BLUE](_BLUE)
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* [_LOADIMAGE](_LOADIMAGE), [_NEWIMAGE](_NEWIMAGE)
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* [HEX$ 32 Bit Values](HEX$-32-Bit-Values), [POINT](POINT)
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* [SAVEIMAGE](SAVEIMAGE)
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* [Hexadecimal Color Values](http://www.w3schools.com/html/html_colornames.asp)
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