/// <summary>
/// Convert Image to grayscale indexed image (like GIF)
/// </summary>
/// <param name="originalImage"></param>
/// <returns></returns>
public static QImage ConvertToGrayScaleIndexed(QImage originalImage)
{
var newImage = new QImage(originalImage.Size, QImage.Format.FormatGrayscale8);
newImage.ColorCount = 256;
for (int i = 0; i < 256; i++)
{
newImage.SetColor(i, qrgb.QRgb(i, i, i));
}
// Add color table for image
// [looking at example](http://stackoverflow.com/questions/5504768/how-to-use-a-color-lut-in-qt-qimage)
for (int x = 0; x < originalImage.Width; x++)
{
for (int y = 0; y < originalImage.Height; y++)
{
var point = new QPoint(x, y); // pixel position
UInt32 pixel = originalImage.Pixel(point);
var gray = qrgb.QGray(pixel);
newImage.SetPixel(point, qrgb.QRgb(gray, gray, gray));
}
}
//newImage.Save ( @"d:\dump.png", "png" );
return(newImage);
}
/// <summary>
/// Convert RGBA image to grayscale RGBA
/// </summary>
/// <param name="originalImage"></param>
/// <returns></returns>
public static QImage ConvertToGrayScale(QImage originalImage)
{
var newImage = originalImage.Copy();
for (int x = 0; x < originalImage.Width; x++)
{
for (int y = 0; y < originalImage.Height; y++)
{
var point = new QPoint(x, y); // pixel position
using (var color = originalImage.PixelColor(point)) {
UInt32 pixel = originalImage.Pixel(point);
int alpha = color.Alpha;
int gray = qrgb.QGray(pixel);
using (var qColor = new QColor(gray, gray, gray, alpha)) {
newImage.SetPixelColor(point, qColor);
}
}
}
}
return(newImage);
}
