HUE32

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.
  • ARGB colors are returned by various functions, such as _PALETTECOLOR, POINT and obviously by the color creating _RGB32, _RGBA32, _HSB32 or _HSBA32 functions.

Description

• The value returned is of type DOUBLE in the range 0 to 360 degrees.
  • 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

• 

  v4.0.0

• 
• 

  yes

• 

  yes

• 

  yes

Examples

Example 1

Showcasing the HSB value retrieving functions and demonstrate the quantization errors.

PRINT "Creating a color using the HSB colorspace..." cOrig~& = _HSB32(90, 75, 65) PRINT "_HSB32( 90, 75, 65 ) = _RGB32("; _RED32(cOrig~&); ","; _GREEN32(cOrig~&); ","; _BLUE32(cOrig~&); ")" PRINT PRINT "Back to HSB values (notice the quantization errors)." PRINT "The HSB color was not accurately representable in RGB." PRINT "Hue.......:"; _HUE32(cOrig~&) PRINT "Saturation:"; _SATURATION32(cOrig~&) PRINT "Brightness:"; _BRIGHTNESS32(cOrig~&) PRINT cBack~& = _HSB32(_HUE32(cOrig~&), _SATURATION32(cOrig~&), _BRIGHTNESS32(cOrig~&)) PRINT "However, when using the retrieved HSB values again for conversion," PRINT "then we definitly get back the exact same RGB color again." PRINT "Red.......:"; _RED32(cBack~&) PRINT "Green.....:"; _GREEN32(cBack~&) PRINT "Blue......:"; _BLUE32(cBack~&) PRINT PRINT "Conclusion:" PRINT "Not every HSB color can be accurately represented in 8-bit integer RGB," PRINT "but every RGB color can be accurately represented in floating point HSB." END

See also

• _HSB32, _HSBA32
• _SATURATION32, _BRIGHTNESS32
• _RGB32, _RGBA32
• _RED32, _GREEN32, _BLUE32, _ALPHA32

---

Navigation: Main Page with Articles and Tutorials Keyword Reference - Alphabetical Keyword Reference - By usage Report a broken link