msdf/MSDF-Test/Glyph.cs

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using System.Diagnostics.CodeAnalysis;
using System.Drawing;
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namespace MSDF_Test;
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[SuppressMessage("Interoperability", "CA1416:Validate platform compatibility")]
internal class Glyph
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{
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private readonly Bitmap _originalBitmap;
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private const float MaxColor = 255; //255 for Bitmaps
private const float DistanceRange = 255; //255 for Bitmaps
public Glyph(Bitmap texture)
{
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this._originalBitmap = texture;
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}
internal Bitmap GetBitmap(int size, Color foreground, Color background)
{
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Bitmap ret = new(size, size, _originalBitmap.PixelFormat);
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for (int x = 0; x < ret.Width; x++)
{
for (int y = 0; y < ret.Height; y++)
{
PointF scaledPoint = new (x, y);
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ret.SetPixel(x, y, GeneratePixel(scaledPoint.Scale((float)_originalBitmap.Width / size)) ? foreground : background);
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}
}
return ret;
}
private bool GeneratePixel(PointF point)
{
Color s = SampleBilinear(point);
float sample = Median(s);
float d = ColorDistance(sample);
return d >= 0;
}
private Color SampleBilinear(PointF point)
{
int x1 = (int)Math.Floor(point.X - .5);
int y1 = (int)Math.Floor(point.Y - .5);
int x2 = x1 + 1;
int y2 = y1 + 1;
double wx = point.X - x1 - .5;
double wy = point.Y - y1 - .5;
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if (x1 >= 0 && y1 >= 0 && x2 <= (_originalBitmap.Width - 1) && y2 <= (_originalBitmap.Height - 1))
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{
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Color x1y1 = _originalBitmap.GetPixel(x1, y1).MultiplyWith((1 - wx) * (1 - wy));
Color x1y2 = _originalBitmap.GetPixel(x1, y2).MultiplyWith((1 - wx) * wy);
Color x2y1 = _originalBitmap.GetPixel(x2, y1).MultiplyWith(wx * (1 - wy));
Color x2y2 = _originalBitmap.GetPixel(x2, y2).MultiplyWith(wx * wy);
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return x1y1.Add(x1y2).Add(x2y1).Add(x2y2);
}
return Color.Black; //Edges can not be interpolated. Just return 0
}
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private static float Median(float r, float g, float b)
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{
return Math.Max(Math.Min(r, g), Math.Min(Math.Max(r, g), b));
}
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private static float Median(Color c) => Median(c.R, c.G, c.B);
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private static float ColorDistance(float sample)
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{
return ((sample / MaxColor) - .5f) * DistanceRange;
}
}