114 lines
4.4 KiB
C#
114 lines
4.4 KiB
C#
using System.Drawing;
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namespace Mk0.Tools.Images
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{
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public class BorderCropper
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{
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#region CropUnwantedBackground
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/// <summary>
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/// Entfernt gleichfarbige Bildränder
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/// </summary>
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/// <param name="bmp">Bild dessen Ränder entfernt werden sollen</param>
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/// <returns>Bild dem die Ränder entfernt wurden</returns>
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public static Bitmap CropUnwantedBackground(Bitmap bmp)
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{
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var backColor = GetMatchedBackColor(bmp);
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if (backColor.HasValue)
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{
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var bounds = GetImageBounds(bmp, backColor);
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var diffX = bounds[1].X - bounds[0].X + 1;
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var diffY = bounds[1].Y - bounds[0].Y + 1;
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var croppedBmp = new Bitmap(diffX, diffY);
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var g = Graphics.FromImage(croppedBmp);
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var destRect = new Rectangle(0, 0, croppedBmp.Width, croppedBmp.Height);
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var srcRect = new Rectangle(bounds[0].X, bounds[0].Y, diffX, diffY);
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g.DrawImage(bmp, destRect, srcRect, GraphicsUnit.Pixel);
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return croppedBmp;
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}
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else
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{
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return null;
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}
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}
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#endregion
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#region Private Methods
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#region GetImageBounds
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private static Point[] GetImageBounds(Bitmap bmp, Color? backColor)
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{
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//--------------------------------------------------------------------
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// Finding the Bounds of Crop Area bu using Unsafe Code and Image Proccesing
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Color c;
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int width = bmp.Width, height = bmp.Height;
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bool upperLeftPointFounded = false;
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var bounds = new Point[2];
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for (int y = 0; y < height; y++)
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{
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for (int x = 0; x < width; x++)
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{
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c = bmp.GetPixel(x, y);
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bool sameAsBackColor = ((c.R <= backColor.Value.R * 1.1 && c.R >= backColor.Value.R * 0.9) &&
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(c.G <= backColor.Value.G * 1.1 && c.G >= backColor.Value.G * 0.9) &&
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(c.B <= backColor.Value.B * 1.1 && c.B >= backColor.Value.B * 0.9));
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if (!sameAsBackColor)
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{
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if (!upperLeftPointFounded)
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{
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bounds[0] = new Point(x, y);
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bounds[1] = new Point(x, y);
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upperLeftPointFounded = true;
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}
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else
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{
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if (x > bounds[1].X)
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bounds[1].X = x;
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else if (x < bounds[0].X)
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bounds[0].X = x;
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if (y >= bounds[1].Y)
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bounds[1].Y = y;
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}
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}
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}
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}
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return bounds;
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}
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#endregion
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#region GetMatchedBackColor
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private static Color? GetMatchedBackColor(Bitmap bmp)
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{
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// Getting The Background Color by checking Corners of Original Image
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var corners = new Point[]{
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new Point(0, 0),
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new Point(0, bmp.Height - 1),
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new Point(bmp.Width - 1, 0),
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new Point(bmp.Width - 1, bmp.Height - 1)
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}; // four corners (Top, Left), (Top, Right), (Bottom, Left), (Bottom, Right)
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for (int i = 0; i < 4; i++)
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{
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var cornerMatched = 0;
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var backColor = bmp.GetPixel(corners[i].X, corners[i].Y);
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for (int j = 0; j < 4; j++)
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{
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var cornerColor = bmp.GetPixel(corners[j].X, corners[j].Y);// Check RGB with some offset
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if ((cornerColor.R <= backColor.R * 1.1 && cornerColor.R >= backColor.R * 0.9) &&
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(cornerColor.G <= backColor.G * 1.1 && cornerColor.G >= backColor.G * 0.9) &&
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(cornerColor.B <= backColor.B * 1.1 && cornerColor.B >= backColor.B * 0.9))
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{
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cornerMatched++;
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}
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}
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if (cornerMatched > 2)
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{
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return backColor;
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}
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}
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return null;
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}
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#endregion
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#endregion
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}
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}
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