private void UpdateColorMapFromControls(bool forceUpdate = false)
{
if (colorMapEditorType != ColorMapEditorType.Controls)
{
return;
}
AllocateColorMapData();
if (forceUpdate ||
!colorMapEditorGradient.Equals(colorMapEditorGradientOld) ||
colorMapEditorContrast_ != colorMapEditorContrast ||
colorMapEditorBrightness_ != colorMapEditorBrightness ||
colorMapEditorPosterize_ != colorMapEditorPosterize)
{
colorMapEditorGradientOld.CopyFrom(colorMapEditorGradient);
colorMapEditorContrast_ = colorMapEditorContrast;
colorMapEditorBrightness_ = colorMapEditorBrightness;
colorMapEditorPosterize_ = colorMapEditorPosterize;
AllocateColorMapData();
// Populate colorMapData
for (int i = 0; i < 256; i++)
{
// Apply contrast, brightness and posterization on the grayscale value
double value = (double)i / 255.0;
// Constrast and brightness
double contrastFactor = colorMapEditorContrast + 1; // UI runs from -1 to 1
value = (value - 0.5) * contrastFactor + 0.5 + colorMapEditorBrightness;
// Posterization
if (colorMapEditorPosterize > 0.0f)
{
// The posterization slider feels more useful if the progression is exponential. The function is emprically tuned.
const double posterizationBase = 50.0;
double posterize = (Math.Pow(posterizationBase, colorMapEditorPosterize) - 1.0) / (posterizationBase - 1.0);
value = Math.Round(value / posterize) * posterize;
}
// Clamp to [0, 1]
value = Math.Min(Math.Max(value, 0.0), 1.0);
// Map to value to color
Color color = colorMapEditorGradient.Evaluate((float)value);
WriteColorToColorMap(i, ref color);
}
styleDirty = true;
}
}
