Difference between revisions of "RGB"

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The {{KW|_RGB}} function returns the closest palette index OR the 32 bit color value in 32 bit screens only.
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{{DISPLAYTITLE:_RGB}}
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The [[_RGB]] function returns the closest palette attribute index (legacy SCREEN modes) OR the [[LONG]] 32-bit color value (32-bit screens).  
  
  
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:{{Parameter|colorindex}} = {{KW|_RGB}}({{Parameter|red}}, {{Parameter|green}}, {{Parameter|blue}}[, {{Parameter|image_handle}}])
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{{PageSyntax}}
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: {{Parameter|colorIndex~&}} = [[_RGB]]({{Parameter|red&}}, {{Parameter|green&}}, {{Parameter|blue&}}[, {{Parameter|imageHandle&}}])
  
  
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* {{Parameter|red&}} specifies the red component intensity.
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{{PageDescription}}
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* {{Parameter|green&}} specifies the green component intensity.
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* The value returned is either the closest color attribute number or a 32-bit [[_UNSIGNED]] [[LONG]] color value.
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* {{Parameter|blue&}} specifies the blue component intensity.
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* '''Return variable types must be [[LONG]] or resulting color may lose the [[_BLUE]] value.'''
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* Valid component intensity values range from 0 (no intensity; color not present) to 255 (full intensity).
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* {{Parameter|red&}} specifies the red component intensity from 0 to 255.
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* Values outside the valid range are clipped.
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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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* Intensity values outside the valid range are clipped.
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* Returns [[LONG]] 32-bit hexadecimal values from '''&HFF{{text|00|red}}{{text|00|green}}{{text|00|blue}}''' to '''&HFF{{text|FF|red}}{{text|FF|green}}{{text|FF|blue}}''', always with full [[_ALPHA]].
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* When [[LONG]] values are [[PUT]] to file, the ARGB values become BGRA. Use [[LEFT$]]([[MKL$]]({{Parameter|colorIndex~&}}), 3) to place 3 colors.
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* If the {{Parameter|imageHandle&}} is omitted the image is assumed to be the current [[_DEST|destination]] or [[SCREEN]] page.
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* Colors returned are always opaque as the transparency value is always 255. Use [[_ALPHA]] or [[_CLEARCOLOR]] to change it.
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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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{{PageExamples}}
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''Example:'' Converting the color port RGB intensity palette values 0 to 63 to 32 bit hexadecimal values.
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{{CodeStart}}
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{{Cl|SCREEN}} 12
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{{Cl|DIM}} hex32$(15)
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{{Cl|FOR...NEXT|FOR}} attribute = 1 {{Cl|TO}} 15
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  {{Cl|OUT}} {{Cl|&H}}3C7, attribute      'set color attribute to read
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  red = {{Cl|INP}}({{Cl|&H}}3C9) * 4      'multiply by 4 to convert intensity to 0 to 255 RGB values
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  grn = {{Cl|INP}}({{Cl|&H}}3C9) * 4
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  blu = {{Cl|INP}}({{Cl|&H}}3C9) * 4
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  hex32$(attribute) = "{{Cl|&H}}" + {{Cl|HEX$}}({{Cl|_RGB32}}(red, grn, blu))  'always returns the 32 bit value
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  {{Cl|COLOR}} attribute
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  {{Cl|PRINT}} "{{Cl|COLOR}}" + {{Cl|STR$}}({{Cl|_RGB}}(red, grn, blu)) + " = " + hex32$(attribute)  'closest attribute
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{{Cl|NEXT}} '' ''
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{{CodeEnd}}
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{{OutputStart}}{{text|COLOR 1 <nowiki>=</nowiki> &HFF0000A8|#0000A8}}
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{{text|COLOR 2 <nowiki>=</nowiki> &HFF00A800|#00A800}}
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{{text|COLOR 3 <nowiki>=</nowiki> &HFF00A8A8|#00A8A8}}
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{{text|COLOR 4 <nowiki>=</nowiki> &HFFA80000|#A80000}}
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{{text|COLOR 5 <nowiki>=</nowiki> &HFFA800A8|#A800A8}}
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{{text|COLOR 6 <nowiki>=</nowiki> &HFFA85400|#A85400}}
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{{text|COLOR 7 <nowiki>=</nowiki> &HFFA8A8A8|#A8A8A8}}
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{{text|COLOR 8 <nowiki>=</nowiki> &HFF545454|#545454}}
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{{text|COLOR 9 <nowiki>=</nowiki> &HFF5454FC|#5454FC}}
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{{text|COLOR 10 <nowiki>=</nowiki> &HFF54FC54|#54FC54}}
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{{text|COLOR 11 <nowiki>=</nowiki> &HFF54FCFC|#54FCFC}}
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{{text|COLOR 12 <nowiki>=</nowiki> &HFFFC5454|#FC5454}}
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{{text|COLOR 13 <nowiki>=</nowiki> &HFFFC54FC|#FC54FC}}
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{{text|COLOR 14 <nowiki>=</nowiki> &HFFFCFC54|#FCFC54}}
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{{text|COLOR 15 <nowiki>=</nowiki> &HFFFCFCFC|#FCFCFC}}
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{{OutputEnd}}
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:''Note:'' This procedure also shows how the returns from [[_RGB]] and [[_RGB32]] differ in a non-32 bit screen mode.
  
  
 
{{PageSeeAlso}}
 
{{PageSeeAlso}}
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*{{KW|_RGBA}}, {{KW|_RGB32}}, {{KW|_RGBA32}}
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* [[_RGBA]], [[_RGB32]], [[_RGBA32]]
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*{{KW|_RED}}, {{KW|_GREEN}}, {{KW|BLUE}}
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* [[_RED]], [[_GREEN]], [[_BLUE]]
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*{{KW|_LOADIMAGE}}
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* [[_LOADIMAGE]], [[_NEWIMAGE]]
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* [[HEX$ 32 Bit Values]], [[POINT]]
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* [[SAVEIMAGE]]
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* [http://www.w3schools.com/html/html_colornames.asp Hexadecimal Color Values]
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{{PageNavigation}}
 
{{PageNavigation}}

Latest revision as of 03:16, 1 November 2017

The _RGB function returns the closest palette attribute index (legacy SCREEN modes) OR the LONG 32-bit color value (32-bit screens).


Syntax

colorIndex~& = _RGB(red&, green&, blue&[, imageHandle&])


Description

  • The value returned is either the closest color attribute number or a 32-bit _UNSIGNED LONG color value.
  • Return variable types must be LONG or resulting color may lose the _BLUE value.
  • red& specifies the red component intensity from 0 to 255.
  • green& specifies the green component intensity from 0 to 255.
  • blue& specifies the blue component intensity from 0 to 255.
  • Intensity values outside the valid range are clipped.
  • Returns LONG 32-bit hexadecimal values from &HFF000000 to &HFFFFFFFF, always with full _ALPHA.
  • When LONG values are PUT to file, the ARGB values become BGRA. Use LEFT$(MKL$(colorIndex~&), 3) to place 3 colors.
  • If the imageHandle& is omitted the image is assumed to be the current destination or SCREEN page.
  • Colors returned are always opaque as the transparency value is always 255. Use _ALPHA or _CLEARCOLOR to change it.
  • NOTE: Default 32-bit backgrounds are clear black or _RGBA(0, 0, 0, 0). Use CLS to make the black opaque.


Examples

Example: Converting the color port RGB intensity palette values 0 to 63 to 32 bit hexadecimal values.

SCREEN 12 DIM hex32$(15) FOR attribute = 1 TO 15 OUT &H3C7, attribute 'set color attribute to read red = INP(&H3C9) * 4 'multiply by 4 to convert intensity to 0 to 255 RGB values grn = INP(&H3C9) * 4 blu = INP(&H3C9) * 4 hex32$(attribute) = "&H" + HEX$(_RGB32(red, grn, blu)) 'always returns the 32 bit value COLOR attribute PRINT "COLOR" + STR$(_RGB(red, grn, blu)) + " = " + hex32$(attribute) 'closest attribute NEXT

COLOR 1 = &HFF0000A8 COLOR 2 = &HFF00A800 COLOR 3 = &HFF00A8A8 COLOR 4 = &HFFA80000 COLOR 5 = &HFFA800A8 COLOR 6 = &HFFA85400 COLOR 7 = &HFFA8A8A8 COLOR 8 = &HFF545454 COLOR 9 = &HFF5454FC COLOR 10 = &HFF54FC54 COLOR 11 = &HFF54FCFC COLOR 12 = &HFFFC5454 COLOR 13 = &HFFFC54FC COLOR 14 = &HFFFCFC54 COLOR 15 = &HFFFCFCFC

Note: This procedure also shows how the returns from _RGB and _RGB32 differ in a non-32 bit screen mode.


See also


Navigation:
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