ColorHLS

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ColorHLS

Screenshot ColorHLS

TColorHLS is a freeware OWL class that represents a color in the HLS modell. It is a stand alone class without inheritance, but it has mostly the same interface as the original TColor class.

The HLS modell is widely used by artists. Its color components are hue, lightness, and saturation.

	Hue has the same meaning as the HSV model, except that a hue angle of 0° corresponds to blue in this model. Magenta is at 60°, red is at 120°. As with the HSV model, complementary colors are 180° apart.
	Lightness (Luminance) is the amount of black or white in a color. Increasing lightness adds white to the hue. Decreasing lightness adds black to the hue.
	Saturation in the HLS model is a measure of the "purity" of a hue. As saturation is decreased, the hue becomes more gray. A saturation value of zero results in a grayscale value.

The HLS modell makes it very easy, to draw such things as color gradients between any color:

void DrawGradient(CDC& dc, int x, int y, TColorHLS c1, TColorHLS c2,
int width, int height)
{
PRECONDITION(width > 0);
float dh = (c2.GetHue() - c1.GetHue()) / width;
float dl = (c2.GetLuminance() - c1.GetLuminance()) / width;
float ds = (c2.GetSaturation() - c1.GetSaturation()) / width;
for (int i = 0; i < width; ++i)
{
    TPen pen(TColor(c1.GetValue()));
    dc.SelectObject(pen);
    dc.MoveTo(x + i, y);
    dc.LineTo(x + i, y + height);
    dc.RestorePen();
    c1.SetHue(c1.GetHue() + dh);
    c1.SetLuminance(c1.GetLuminance() + dl);
    c1.SetSaturation(c1.GetSaturation() + ds);
}
}

Perhaps NT 5.0 will support the HLS (or the similary HSB) color modell.

Portions of code are based on MFC class CColor written by Christian Rodemeyer. Very special thanks.

The code was tested using Microsoft Visual C++ 6.0 SR2 with OWL6 patch 7 and Borland C++ 5.02 with OWL 5.02. Both under Windows NT 4.0 SP4.

Please send me bug reports, bug fixes, enhancements, requests, etc., and I'll try to keep this in next versions:
EMail: dieter.windau@usa.net

Happy coding

Download

Ver	File	Description
1.02	06/05/99, 7 KB	Only the source of TColorHLS class and this HTML-Document
-	06/05/99, 39 KB	The sample application demonstrates the use of the TColorHLS class

History

Ver	Date	Description
1.02	06/05/99	Stream operators work with VC++ now. Very special thanks to Yura Bidus.
1.01	05/09/99	Limit the values in SetHue(), SetLuminance(), SetSaturation()
1.0	04/24/99	Basic version.