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Diffstat (limited to 'Emby.Drawing.Net/ImageExtensions.cs')
| -rw-r--r-- | Emby.Drawing.Net/ImageExtensions.cs | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/Emby.Drawing.Net/ImageExtensions.cs b/Emby.Drawing.Net/ImageExtensions.cs new file mode 100644 index 000000000..dec2613d0 --- /dev/null +++ b/Emby.Drawing.Net/ImageExtensions.cs @@ -0,0 +1,217 @@ +using System; +using System.Drawing; +using System.Drawing.Drawing2D; +using System.Drawing.Imaging; +using System.IO; + +namespace Emby.Drawing.Net +{ + public static class ImageExtensions + { + /// <summary> + /// Saves the image. + /// </summary> + /// <param name="outputFormat">The output format.</param> + /// <param name="image">The image.</param> + /// <param name="toStream">To stream.</param> + /// <param name="quality">The quality.</param> + public static void Save(this Image image, ImageFormat outputFormat, Stream toStream, int quality) + { + // Use special save methods for jpeg and png that will result in a much higher quality image + // All other formats use the generic Image.Save + if (ImageFormat.Jpeg.Equals(outputFormat)) + { + SaveAsJpeg(image, toStream, quality); + } + else if (ImageFormat.Png.Equals(outputFormat)) + { + image.Save(toStream, ImageFormat.Png); + } + else + { + image.Save(toStream, outputFormat); + } + } + + /// <summary> + /// Saves the JPEG. + /// </summary> + /// <param name="image">The image.</param> + /// <param name="target">The target.</param> + /// <param name="quality">The quality.</param> + public static void SaveAsJpeg(this Image image, Stream target, int quality) + { + using (var encoderParameters = new EncoderParameters(1)) + { + encoderParameters.Param[0] = new EncoderParameter(Encoder.Quality, quality); + image.Save(target, GetImageCodecInfo("image/jpeg"), encoderParameters); + } + } + + private static readonly ImageCodecInfo[] Encoders = ImageCodecInfo.GetImageEncoders(); + + /// <summary> + /// Gets the image codec info. + /// </summary> + /// <param name="mimeType">Type of the MIME.</param> + /// <returns>ImageCodecInfo.</returns> + private static ImageCodecInfo GetImageCodecInfo(string mimeType) + { + foreach (var encoder in Encoders) + { + if (string.Equals(encoder.MimeType, mimeType, StringComparison.OrdinalIgnoreCase)) + { + return encoder; + } + } + + return Encoders.Length == 0 ? null : Encoders[0]; + } + + /// <summary> + /// Crops an image by removing whitespace and transparency from the edges + /// </summary> + /// <param name="bmp">The BMP.</param> + /// <returns>Bitmap.</returns> + /// <exception cref="System.Exception"></exception> + public static Bitmap CropWhitespace(this Bitmap bmp) + { + var width = bmp.Width; + var height = bmp.Height; + + var topmost = 0; + for (int row = 0; row < height; ++row) + { + if (IsAllWhiteRow(bmp, row, width)) + topmost = row; + else break; + } + + int bottommost = 0; + for (int row = height - 1; row >= 0; --row) + { + if (IsAllWhiteRow(bmp, row, width)) + bottommost = row; + else break; + } + + int leftmost = 0, rightmost = 0; + for (int col = 0; col < width; ++col) + { + if (IsAllWhiteColumn(bmp, col, height)) + leftmost = col; + else + break; + } + + for (int col = width - 1; col >= 0; --col) + { + if (IsAllWhiteColumn(bmp, col, height)) + rightmost = col; + else + break; + } + + if (rightmost == 0) rightmost = width; // As reached left + if (bottommost == 0) bottommost = height; // As reached top. + + var croppedWidth = rightmost - leftmost; + var croppedHeight = bottommost - topmost; + + if (croppedWidth == 0) // No border on left or right + { + leftmost = 0; + croppedWidth = width; + } + + if (croppedHeight == 0) // No border on top or bottom + { + topmost = 0; + croppedHeight = height; + } + + // Graphics.FromImage will throw an exception if the PixelFormat is Indexed, so we need to handle that here + var thumbnail = new Bitmap(croppedWidth, croppedHeight, PixelFormat.Format32bppPArgb); + + // Preserve the original resolution + TrySetResolution(thumbnail, bmp.HorizontalResolution, bmp.VerticalResolution); + + using (var thumbnailGraph = Graphics.FromImage(thumbnail)) + { + thumbnailGraph.CompositingQuality = CompositingQuality.HighQuality; + thumbnailGraph.SmoothingMode = SmoothingMode.HighQuality; + thumbnailGraph.InterpolationMode = InterpolationMode.HighQualityBicubic; + thumbnailGraph.PixelOffsetMode = PixelOffsetMode.HighQuality; + thumbnailGraph.CompositingMode = CompositingMode.SourceCopy; + + thumbnailGraph.DrawImage(bmp, + new RectangleF(0, 0, croppedWidth, croppedHeight), + new RectangleF(leftmost, topmost, croppedWidth, croppedHeight), + GraphicsUnit.Pixel); + } + return thumbnail; + } + + /// <summary> + /// Tries the set resolution. + /// </summary> + /// <param name="bmp">The BMP.</param> + /// <param name="x">The x.</param> + /// <param name="y">The y.</param> + private static void TrySetResolution(Bitmap bmp, float x, float y) + { + if (x > 0 && y > 0) + { + bmp.SetResolution(x, y); + } + } + + /// <summary> + /// Determines whether or not a row of pixels is all whitespace + /// </summary> + /// <param name="bmp">The BMP.</param> + /// <param name="row">The row.</param> + /// <param name="width">The width.</param> + /// <returns><c>true</c> if [is all white row] [the specified BMP]; otherwise, <c>false</c>.</returns> + private static bool IsAllWhiteRow(Bitmap bmp, int row, int width) + { + for (var i = 0; i < width; ++i) + { + if (!IsWhiteSpace(bmp.GetPixel(i, row))) + { + return false; + } + } + return true; + } + + /// <summary> + /// Determines whether or not a column of pixels is all whitespace + /// </summary> + /// <param name="bmp">The BMP.</param> + /// <param name="col">The col.</param> + /// <param name="height">The height.</param> + /// <returns><c>true</c> if [is all white column] [the specified BMP]; otherwise, <c>false</c>.</returns> + private static bool IsAllWhiteColumn(Bitmap bmp, int col, int height) + { + for (var i = 0; i < height; ++i) + { + if (!IsWhiteSpace(bmp.GetPixel(col, i))) + { + return false; + } + } + return true; + } + + /// <summary> + /// Determines if a color is whitespace + /// </summary> + /// <param name="color">The color.</param> + /// <returns><c>true</c> if [is white space] [the specified color]; otherwise, <c>false</c>.</returns> + private static bool IsWhiteSpace(Color color) + { + return (color.R == 255 && color.G == 255 && color.B == 255) || color.A == 0; + } + } +} |