Uses BGRABitmap, BGRABitmapTypes, XYZABitmap procedure TForm1. To render on screen, the bitmap needs to be drawn on a BGRA bitmap. So in this case, we need to prepare a bitmap that is twice as big and in the end draw it zoomed out. In theory the Y channel can be greater than one as well if it expresses a light source stronger than the illuminant, but that will saturate when rendering it on a screen.Īlso here the GetCanvasScaleFactor function (value 1 or greater) is used to determine if there is a Retina display for which the coordinates can be double the pixel size. The X and Z channels can be greater than one depending on the illuminant and typically in daylight the Z value for the brightest white is slightly greater than 1. In the example, the Y value (lightness) is set to 0.5 while the X and Z values varies to express different hues. The TXYZA type contains floating point values from 0 to 1. Instead of converting directly the values of pixels, it is possible to use a bitmap with another pixel format. With full color correction, the gradient is more progressive, and looks like what you would obtain with the Lab color model. Note that the THSLAPixel type is used, whatever the correction of the color model. InvalidateBitmap // changed by direct access image. Width p ^:= GSBAToBGRA ( hsla ) inc ( p ) end end image. Create ( ClientWidth, ClientHeight ) hsla. FormPaint ( Sender : TObject ) var x, y : integer p : PBGRAPixel image : TBGRABitmap hsla : THSLAPixel begin image := TBGRABitmap. The functions HtoG and GtoH apply or unapply a correction, where in the G hue, ranges are not of the same size. However, we do not perceive the same differences of colors in these different ranges. In the classical version of HSLA model, each range between primary colors (red/green/blue) is represented by 120 degrees, which equals 21845 colors in THSLAPixel. HSLA colors have gamma correction, but there are other possible corrections. Width p ^:= HSLAToBGRA ( hsla ) inc ( p ) end end image.

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