mirror of https://github.com/SixLabors/ImageSharp
James South
13 years ago
6 changed files with 249 additions and 110 deletions
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using System.Collections.Generic; |
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using System.Drawing; |
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using System.Text.RegularExpressions; |
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using ImageProcessor.Helpers.Extensions; |
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namespace ImageProcessor.Processors |
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{ |
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/// <summary>
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/// Constrains an image to the given dimensions.
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/// </summary>
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public class Constrain : ResizeBase |
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{ |
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private static readonly Regex QueryRegex = new Regex(@"constrain=\d+,\d+", RegexOptions.Compiled); |
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public override Regex RegexPattern |
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{ |
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get |
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{ |
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return QueryRegex; |
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} |
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} |
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public override dynamic DynamicParameter { get; set; } |
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public override int SortOrder { get; protected set; } |
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public override Dictionary<string, string> Settings { get; set; } |
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public override int MatchRegexIndex(string queryString) |
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{ |
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int index = 0; |
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// Set the sort order to max to allow filtering.
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this.SortOrder = int.MaxValue; |
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foreach (Match match in this.RegexPattern.Matches(queryString)) |
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{ |
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if (match.Success) |
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{ |
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if (index == 0) |
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{ |
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// Set the index on the first instance only.
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this.SortOrder = match.Index; |
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int[] constraints = match.Value.ToPositiveIntegerArray(); |
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int x = constraints[0]; |
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int y = constraints[1]; |
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this.DynamicParameter = new Size(x, y); |
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} |
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index += 1; |
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} |
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} |
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return this.SortOrder; |
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} |
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public override Image ProcessImage(ImageFactory factory) |
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{ |
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double constrainedWidth = DynamicParameter.Width; |
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double constrainedHeight = DynamicParameter.Height; |
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var original = factory.Image; |
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double width = original.Width; |
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double height = original.Height; |
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if (width > constrainedWidth || height > constrainedHeight) |
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{ |
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double constraintRatio = constrainedHeight / constrainedWidth; |
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double originalRatio = height / width; |
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Size newSize = originalRatio < constraintRatio |
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? new Size((int)constrainedWidth, 0) |
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: new Size(0, (int)constrainedHeight); |
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int defaultMaxWidth; |
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int defaultMaxHeight; |
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int.TryParse(this.Settings["MaxWidth"], out defaultMaxWidth); |
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int.TryParse(this.Settings["MaxHeight"], out defaultMaxHeight); |
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return ResizeImage(factory, newSize.Width, newSize.Height, defaultMaxWidth, defaultMaxHeight); |
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} |
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return factory.Image; |
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} |
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} |
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} |
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@ -0,0 +1,104 @@ |
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using System; |
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using System.Collections.Generic; |
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using System.Drawing; |
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using System.Drawing.Drawing2D; |
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using System.Drawing.Imaging; |
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using System.Text.RegularExpressions; |
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namespace ImageProcessor.Processors |
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{ |
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public abstract class ResizeBase : IGraphicsProcessor |
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{ |
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public abstract Regex RegexPattern { get; } |
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public abstract dynamic DynamicParameter { get; set; } |
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public abstract int SortOrder { get; protected set; } |
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public abstract Dictionary<string, string> Settings { get; set; } |
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public abstract int MatchRegexIndex(string queryString); |
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public abstract Image ProcessImage(ImageFactory factory); |
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protected Image ResizeImage(ImageFactory factory, int width, int height, int defaultMaxWidth, int defaultMaxHeight) |
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{ |
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Bitmap newImage = null; |
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Image image = factory.Image; |
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try |
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{ |
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int sourceWidth = image.Width; |
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int sourceHeight = image.Height; |
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int maxWidth = defaultMaxWidth > 0 ? defaultMaxWidth : int.MaxValue; |
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int maxHeight = defaultMaxHeight > 0 ? defaultMaxHeight : int.MaxValue; |
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// If height or width is not passed we assume that the standard ratio is to be kept.
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if (height == 0) |
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{ |
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// Bit of simple fractional maths here.
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float percentWidth = Math.Abs(width/(float) sourceWidth); |
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height = (int) Math.Floor(sourceHeight*percentWidth); |
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} |
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if (width == 0) |
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{ |
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float percentHeight = Math.Abs(height/(float) sourceHeight); |
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width = (int) Math.Floor(sourceWidth*percentHeight); |
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} |
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if (width > 0 && height > 0 && width <= maxWidth && height <= maxHeight) |
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{ |
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// Dont use an object initializer here.
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newImage = new Bitmap(width, height, PixelFormat.Format32bppPArgb); |
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newImage.Tag = image.Tag; |
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using (Graphics graphics = Graphics.FromImage(newImage)) |
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{ |
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// We want to use two different blending algorithms for enlargement/shrinking.
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// Bicubic is better enlarging for whilst Bilinear is better for shrinking.
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// http://www.codinghorror.com/blog/2007/07/better-image-resizing.html
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if (image.Width < width && image.Height < height) |
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{ |
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// We are making it larger.
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graphics.SmoothingMode = SmoothingMode.AntiAlias; |
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graphics.InterpolationMode = InterpolationMode.HighQualityBicubic; |
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graphics.PixelOffsetMode = PixelOffsetMode.HighQuality; |
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graphics.CompositingQuality = CompositingQuality.HighQuality; |
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} |
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else |
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{ |
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// We are making it smaller.
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graphics.SmoothingMode = SmoothingMode.None; |
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// Contrary to everything I have read bicubic is producing the best results.
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graphics.InterpolationMode = InterpolationMode.HighQualityBicubic; |
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graphics.PixelOffsetMode = PixelOffsetMode.None; |
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graphics.CompositingQuality = CompositingQuality.HighSpeed; |
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} |
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// An unwanted border appears when using InterpolationMode.HighQualityBicubic to resize the image
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// as the algorithm appears to be pulling averaging detail from surFlooring pixels beyond the edge
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// of the image. Using the ImageAttributes class to specify that the pixels beyond are simply mirror
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// images of the pixels within solves this problem.
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using (ImageAttributes wrapMode = new ImageAttributes()) |
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{ |
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wrapMode.SetWrapMode(WrapMode.TileFlipXY); |
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Rectangle destRect = new Rectangle(0, 0, width, height); |
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graphics.DrawImage(image, destRect, 0, 0, sourceWidth, sourceHeight, GraphicsUnit.Pixel, wrapMode); |
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} |
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// Reassign the image.
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image.Dispose(); |
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image = newImage; |
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} |
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} |
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} |
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catch |
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{ |
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if (newImage != null) |
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{ |
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newImage.Dispose(); |
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} |
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} |
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return image; |
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} |
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} |
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} |
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