HUE32: Difference between revisions

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:* However, this function is not suitable for the HSL (L=Lightness) colorspace, which is widely used in the Web/CSS.
:* However, this function is not suitable for the HSL (L=Lightness) colorspace, which is widely used in the Web/CSS.
;Precision drawbacks
;Precision drawbacks
:* When converting between colorspaces, rounding errors can occur. While the HSB colorspace has virtually infinite precision only limited by the used floating point type, RGB is represented in 8-bit integers (0-255) only, which can lead to quantization errors. In fact, not all colors in HSB can be accurately represented in RGB and vice versa.
:* When converting between colorspaces, rounding errors can occur.
:* However, if you limit yourself to only passing integer values to [[_HSB32]] or [[_HSBA32]], just as you do for the respective RGB colorspace functions [[_RGB32]] or [[_RGBA32]], then you can get back that exact values by [[CINT]]ing the results returned by [[_HUE32]], [[_SATURATION32]] and [[_BRIGHTNESS32]].
:* While the HSB colorspace has virtually infinite precision using floating point values, RGB is limited to 8-bit integers (0-255) only, which can lead to quantization errors.
:* In fact, not all colors in HSB can be accurately represented in RGB, but the opposite is possible.
:* It can be guaranteed, that the [[_HUE32]], [[_SATURATION32]] and [[_BRIGHTNESS32]] values retrieved from any arbitrary RGB color will reproduce the exact same RGB color when passed back through [[_HSB32]].




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{{CodeStart}}
{{CodeStart}}
{{Cl|PRINT}} {{Text|<nowiki>"Creating a color using the HSB colorspace..."</nowiki>|#FFB100}}
{{Cl|PRINT}} {{Text|<nowiki>"Creating a color using the HSB colorspace..."</nowiki>|#FFB100}}
c~& = {{Cl|_HSB32}}({{Text|90|#F580B1}}, {{Text|75|#F580B1}}, {{Text|65|#F580B1}})
c~&amp; = {{Cl|_HSB32}}({{Text|90|#F580B1}}, {{Text|75|#F580B1}}, {{Text|65|#F580B1}})


{{Cl|PRINT}} {{Text|<nowiki>"_HSB32( 90, 75, 65 ) = _RGB32("</nowiki>|#FFB100}}; {{Cl|_RED32}}(c~&); {{Text|<nowiki>","</nowiki>|#FFB100}}; {{Cl|_GREEN32}}(c~&); {{Text|<nowiki>","</nowiki>|#FFB100}}; {{Cl|_BLUE32}}(c~&); {{Text|<nowiki>")"</nowiki>|#FFB100}}
{{Cl|PRINT}} {{Text|<nowiki>"_HSB32( 90, 75, 65 ) = _RGB32("</nowiki>|#FFB100}}; {{Cl|_RED32}}(c~&amp;); {{Text|<nowiki>","</nowiki>|#FFB100}}; {{Cl|_GREEN32}}(c~&amp;); {{Text|<nowiki>","</nowiki>|#FFB100}}; {{Cl|_BLUE32}}(c~&amp;); {{Text|<nowiki>")"</nowiki>|#FFB100}}
{{Cl|PRINT}}
{{Cl|PRINT}}
{{Cl|PRINT}} {{Text|<nowiki>"back to HSB values (notice the precision loss)..."</nowiki>|#FFB100}}
{{Cl|PRINT}} {{Text|<nowiki>"back to HSB values (notice the precision loss)..."</nowiki>|#FFB100}}
{{Cl|PRINT}} {{Text|<nowiki>"Hue.......:"</nowiki>|#FFB100}}; {{Cl|_HUE32}}(c~&)
{{Cl|PRINT}} {{Text|<nowiki>"Hue.......:"</nowiki>|#FFB100}}; {{Cl|_HUE32}}(c~&amp;)
{{Cl|PRINT}} {{Text|<nowiki>"Saturation:"</nowiki>|#FFB100}}; {{Cl|_SATURATION32}}(c~&)
{{Cl|PRINT}} {{Text|<nowiki>"Saturation:"</nowiki>|#FFB100}}; {{Cl|_SATURATION32}}(c~&amp;)
{{Cl|PRINT}} {{Text|<nowiki>"Brightness:"</nowiki>|#FFB100}}; {{Cl|_BRIGHTNESS32}}(c~&)
{{Cl|PRINT}} {{Text|<nowiki>"Brightness:"</nowiki>|#FFB100}}; {{Cl|_BRIGHTNESS32}}(c~&amp;)
{{Cl|PRINT}}
{{Cl|PRINT}}
{{Cl|PRINT}} {{Text|<nowiki>"but with CINT() we can get back the original values..."</nowiki>|#FFB100}}
{{Cl|PRINT}} {{Text|<nowiki>"but with CINT() we can get back the original values..."</nowiki>|#FFB100}}
{{Cl|PRINT}} {{Text|<nowiki>"Hue.......:"</nowiki>|#FFB100}}; {{Cl|CINT}}({{Cl|_HUE32}}(c~&))
{{Cl|PRINT}} {{Text|<nowiki>"Hue.......:"</nowiki>|#FFB100}}; {{Cl|CINT}}({{Cl|_HUE32}}(c~&amp;))
{{Cl|PRINT}} {{Text|<nowiki>"Saturation:"</nowiki>|#FFB100}}; {{Cl|CINT}}({{Cl|_SATURATION32}}(c~&))
{{Cl|PRINT}} {{Text|<nowiki>"Saturation:"</nowiki>|#FFB100}}; {{Cl|CINT}}({{Cl|_SATURATION32}}(c~&amp;))
{{Cl|PRINT}} {{Text|<nowiki>"Brightness:"</nowiki>|#FFB100}}; {{Cl|CINT}}({{Cl|_BRIGHTNESS32}}(c~&))
{{Cl|PRINT}} {{Text|<nowiki>"Brightness:"</nowiki>|#FFB100}}; {{Cl|CINT}}({{Cl|_BRIGHTNESS32}}(c~&amp;))


{{Cl|END}}
{{Cl|END}}

Revision as of 18:47, 30 January 2025

The _HUE32 function returns the hue value (HSB colorspace) of a given 32-bit ARGB color.


Syntax

hue# = _HUE32(argbColor~&)


Parameters

  • argbColor~& is the 32-bit ARGB color value to retrieve the hue value from.


Description

  • The value returned is of type DOUBLE in the range 0 to 360 degrees, use CINT to work with integers only.
    • The color wheel starts with red(0), turns to yellow(60), green(120), cyan(180), blue(240), magenta(300) to red(360) again.
    • Mixed colors are represented by values between those 6 base color angles.
Naming differences
  • The HSB (B=Brightness) colorspace is also known as HSV (V=Value) and sometimes even called HSI (I=Intensity), but that's all just different names for the same thing.
  • However, this function is not suitable for the HSL (L=Lightness) colorspace, which is widely used in the Web/CSS.
Precision drawbacks
  • When converting between colorspaces, rounding errors can occur.
  • While the HSB colorspace has virtually infinite precision using floating point values, RGB is limited to 8-bit integers (0-255) only, which can lead to quantization errors.
  • In fact, not all colors in HSB can be accurately represented in RGB, but the opposite is possible.
  • It can be guaranteed, that the _HUE32, _SATURATION32 and _BRIGHTNESS32 values retrieved from any arbitrary RGB color will reproduce the exact same RGB color when passed back through _HSB32.


Availability

  • none

    none

  • v4.0.0

    v4.0.0

  • Apix.png
  • yes

    yes

  • yes

    yes

  • yes

    yes


Examples

PRINT "Creating a color using the HSB colorspace..."
c~& = _HSB32(90, 75, 65)

PRINT "_HSB32( 90, 75, 65 ) = _RGB32("; _RED32(c~&); ","; _GREEN32(c~&); ","; _BLUE32(c~&); ")"
PRINT
PRINT "back to HSB values (notice the precision loss)..."
PRINT "Hue.......:"; _HUE32(c~&)
PRINT "Saturation:"; _SATURATION32(c~&)
PRINT "Brightness:"; _BRIGHTNESS32(c~&)
PRINT
PRINT "but with CINT() we can get back the original values..."
PRINT "Hue.......:"; CINT(_HUE32(c~&))
PRINT "Saturation:"; CINT(_SATURATION32(c~&))
PRINT "Brightness:"; CINT(_BRIGHTNESS32(c~&))

END


See also


Navigation:
Main Page with Articles and Tutorials
Keyword Reference - Alphabetical
Keyword Reference - By usage
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