public void ShouldThresholdTheSpecifiedChannel()
{
using (var image = new MagickImage(Files.MagickNETIconPNG))
{
image.BlackThreshold(new Percentage(90), Channels.Green);
ColorAssert.Equal(new MagickColor("#3400bd"), image, 43, 74);
ColorAssert.Equal(new MagickColor("#a800f8"), image, 60, 74);
}
}
public void ShouldThresholdTheImage()
{
using (var image = new MagickImage(Files.MagickNETIconPNG))
{
image.BlackThreshold(new Percentage(90));
ColorAssert.Equal(MagickColors.Black, image, 43, 74);
ColorAssert.Equal(new MagickColor("#0000f8"), image, 60, 74);
}
}
private static byte[] PreprocessImage(IMagickImage sourceImage, Rectangle cropRegion, float scale,
string cropRegionPath = "")
{
using var mImage = new MagickImage(MagickColors.White, cropRegion.Width, cropRegion.Height);
mImage.Format = MagickFormat.Png;
if (cropRegion.Width > 0 && cropRegion.Height > 0)
{
mImage.CopyPixels(sourceImage,
new MagickGeometry(cropRegion.X, cropRegion.Y, cropRegion.Width, cropRegion.Height));
}
else
{
mImage.CopyPixels(sourceImage);
}
mImage.Threshold(new Percentage(65f)); // 60 is OK
mImage.Depth = 1;
// mImage.GammaCorrect(0.20); //0.20
// mImage.BlackThreshold(new Percentage(50f), Channels.RGB);
mImage.ColorSpace = ColorSpace.Gray;
mImage.Negate(Channels.RGB);
if (scale != 0f && !(Math.Abs(scale - 1f) < float.Epsilon))
{
mImage.FilterType = FilterType.Cubic;
mImage.Resize(new Percentage(scale * 100.0f));
}
mImage.BlackThreshold(new Percentage(55f), Channels.RGB);
mImage.GaussianBlur(0.85, 0.85);
// mImage.BlackThreshold(new Percentage(50f), Channels.RGB);
// mImage.MedianFilter(2);
// mImage.BlackThreshold(new Percentage(20f), Channels.RGB);
if (!string.IsNullOrEmpty(cropRegionPath))
{
mImage.Write(cropRegionPath);
}
return(mImage.ToByteArray());
}