blocks|key|1702782|text|在我看来，当你使用GDI%2B绘制图像时，它的伸缩性非常好。您可以使用此选项来创建缩放图像。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1702783|如果你想用GDI%2B缩放你的图像，你可以这样做：|1702784|Bitmap+original+=+...
Bitmap+scaled+=+new+Bitmap(new+Size(original.Width+*+4,+original.Height+*+4));
using+(Graphics+graphics+=+Graphics.FromImage(scaled))+{
++graphics.DrawImage(original,+new+Rectangle(0,+0,+scaled.Width,+scaled.Height));
}|code-block|syntax|javascript|1702785|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

When you draw the image using GDI+ it scales quite well in my opinion. You can use this to create a scaled image.

If you want to scale your image with GDI+ you can do something like this:

<pre><code>Bitmap original = ...
Bitmap scaled = new Bitmap(new Size(original.Width * 4, original.Height * 4));
using (Graphics graphics = Graphics.FromImage(scaled)) {
 graphics.DrawImage(original, new Rectangle(0, 0, scaled.Width, scaled.Height));
}
</code></pre>

blocks|key|1702820|text|经过测试的库，如Imagemagick和GD，可用于.NET|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1702821|你也可以读一些像双三次插值这样的东西，然后写你自己的。|1702822|entityMap|0|LINK|mutability|MUTABLE|url|http://www.imagemagick.org/|1|http://gd-sharp.sourceforge.net/^0|8|B|0|K|2|1|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@$A|Q|B|R|1|S]|$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|X|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]|N|$5|I|J|K|C|$L|O]]]]

Tested libraries like <a href="http://www.imagemagick.org/" rel="nofollow noreferrer">Imagemagick</a> and <a href="http://gd-sharp.sourceforge.net/" rel="nofollow noreferrer">GD</a> are available for .NET

You could also read up on things like bicubic interpolation and write your own.

blocks|key|1487772|text|尝试不同的Graphics.InterpolationMode值。在GDI%2B中有几种典型的缩放算法。如果其中一个足以满足您的需要，您可以使用此方法，而不是依赖外部库。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1487773|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Try the different values for Graphics.InterpolationMode. There are several typical scaling algorithms available in GDI+. If one of these is sufficient for your need, you can go this route instead of relying on an external library.

blocks|key|1487839|text|有一个关于使用.NET的GDI%2B来使用双三次插值来调整照片大小的article+on+Code+Project。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1487840|在另一个博客上也有关于这个话题的文章(我想是微软员工)，但我在任何地方都找不到链接。:(也许其他人可以找到它？|1487841|entityMap|0|LINK|mutability|MUTABLE|url|http://www.codeproject.com/KB/GDI-plus/imageresize.aspx^0|W|N|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

There's an <a href="http://www.codeproject.com/KB/GDI-plus/imageresize.aspx" rel="nofollow noreferrer">article on Code Project</a> about using GDI+ for .NET to do photo resizing using, say, Bicubic interpolation.

There was also another article about this topic on another blog (MS employee, I think), but I can't find the link anywhere. :( Perhaps someone else can find it?

blocks|key|1702958|text|您可以尝试我公司的产品之一dotImage，它包含一个object+for+resampling图像，其中包含用于各种质量级别的18+filter+types。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1702959|典型用法是：|1702960|//+BiCubic+is+one+technique+available+in+PhotoShop
ResampleCommand+resampler+=+new+ResampleCommand(newSize,+ResampleMethod.BiCubic);
AtalaImage+newImage+=+resampler.Apply(oldImage).Image;|code-block|syntax|javascript|1702961|此外，dotImage还包含140多个奇怪的图像处理命令，其中包括许多与PhotoShop中的滤镜类似的滤镜，如果这就是你要找的。|1702962|entityMap|0|LINK|mutability|MUTABLE|url|http://www.atalasoft.com/products/dotimage/|1|http://www.atalasoft.com/products/dotimage/docs/Atalasoft.dotImage~Atalasoft.Imaging.ImageProcessing.ResampleCommand_members.html|2|http://www.atalasoft.com/products/dotimage/docs/Atalasoft.dotImage~Atalasoft.Imaging.ImageProcessing.ResampleMethod.html^0|D|8|0|R|L|1|1S|F|2|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]|$A|12|B|13|1|14]|$A|15|B|16|1|17]]|C|$]]|$1|D|3|E|5|6|7|18|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|19|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|1A|8|@]|9|@]|C|$]]|$1|M|3|-4|5|6|7|1B|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]|W|$5|P|Q|R|C|$S|X]]]]

You can try <a href="http://www.atalasoft.com/products/dotimage/" rel="nofollow noreferrer">dotImage</a>, one of my company's products, which includes an <a href="http://www.atalasoft.com/products/dotimage/docs/Atalasoft.dotImage~Atalasoft.Imaging.ImageProcessing.ResampleCommand_members.html" rel="nofollow noreferrer">object for resampling</a> images that has <a href="http://www.atalasoft.com/products/dotimage/docs/Atalasoft.dotImage~Atalasoft.Imaging.ImageProcessing.ResampleMethod.html" rel="nofollow noreferrer">18 filter types</a> for various levels of quality.

Typical usage is:

<pre><code>// BiCubic is one technique available in PhotoShop
ResampleCommand resampler = new ResampleCommand(newSize, ResampleMethod.BiCubic);
AtalaImage newImage = resampler.Apply(oldImage).Image;
</code></pre>

in addition, dotImage includes 140 some odd image processing commands including many filters similar to those in PhotoShop, if that's what you're looking for.

blocks|key|1702988|text|这是我发现在Paint.NET的图像重采样代码中引用的一篇文章:+Paul+Bourke的Various+Simple+Image+Processing+Techniques。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1702989|entityMap|0|LINK|mutability|MUTABLE|url|http://paulbourke.net/texture_colour/imageprocess/^0|19|16|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

This is an article I spotted being referenced in Paint.NET's code for image resampling: <a href="http://paulbourke.net/texture_colour/imageprocess/" rel="nofollow noreferrer">Various Simple Image Processing Techniques</a> by Paul Bourke.

blocks|key|1487970|text|如果是lowres+cgi+2D+Image+Filter，你可以试试这个|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1487971|entityMap|0|LINK|mutability|MUTABLE|url|http://code.google.com/p/2dimagefilter/^0|E|F|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

you could try this one if it's a lowres cgi
<a href="http://code.google.com/p/2dimagefilter/" rel="nofollow noreferrer">2D Image Filter</a>

blocks|key|1703089|text|这可能会有帮助|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1703090|++++public+Image+ResizeImage(Image+source,+RectangleF+destinationBounds)
++++{
++++++++RectangleF+sourceBounds+=+new+RectangleF(0.0f,0.0f,(float)source.Width,+(float)source.Height);
++++++++RectangleF+scaleBounds+=+new+RectangleF();

++++++++Image+destinationImage+=+new+Bitmap((int)destinationBounds.Width,+(int)destinationBounds.Height);
++++++++Graphics+graph+=+Graphics.FromImage(destinationImage);
++++++++graph.InterpolationMode+=
++++++++++++System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

++++++++//+Fill+with+background+color
++++++++graph.FillRectangle(new+SolidBrush(System.Drawing.Color.White),+destinationBounds);

++++++++float+resizeRatio,+sourceRatio;
++++++++float+scaleWidth,+scaleHeight;

++++++++sourceRatio+=+(float)source.Width+/+(float)source.Height;

++++++++if+(sourceRatio+>=+1.0f)
++++++++{
++++++++++++//landscape
++++++++++++resizeRatio+=+destinationBounds.Width+/+sourceBounds.Width;
++++++++++++scaleWidth+=+destinationBounds.Width;
++++++++++++scaleHeight+=+sourceBounds.Height+*+resizeRatio;
++++++++++++float+trimValue+=+destinationBounds.Height+-+scaleHeight;
++++++++++++graph.DrawImage(source,+0,+(trimValue+/+2),+destinationBounds.Width,+scaleHeight);
++++++++}
++++++++else
++++++++{
++++++++++++//portrait
++++++++++++resizeRatio+=+destinationBounds.Height/sourceBounds.Height;
++++++++++++scaleWidth+=+sourceBounds.Width+*+resizeRatio;
++++++++++++scaleHeight+=+destinationBounds.Height;
++++++++++++float+trimValue+=+destinationBounds.Width+-+scaleWidth;
++++++++++++graph.DrawImage(source,+(trimValue+/+2),+0,+scaleWidth,+destinationBounds.Height);
++++++++}

++++++++return+destinationImage;

++++}|code-block|syntax|javascript|1703091|注意InterpolationMode.HighQualityBicubic+->这通常是性能和结果之间的一个很好的折衷。|offset|length|style|CODE|1703092|entityMap^0|0|0|2|10|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

This might help

<pre><code> public Image ResizeImage(Image source, RectangleF destinationBounds)
 {
 RectangleF sourceBounds = new RectangleF(0.0f,0.0f,(float)source.Width, (float)source.Height);
 RectangleF scaleBounds = new RectangleF();

 Image destinationImage = new Bitmap((int)destinationBounds.Width, (int)destinationBounds.Height);
 Graphics graph = Graphics.FromImage(destinationImage);
 graph.InterpolationMode =
 System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;

 // Fill with background color
 graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), destinationBounds);

 float resizeRatio, sourceRatio;
 float scaleWidth, scaleHeight;

 sourceRatio = (float)source.Width / (float)source.Height;

 if (sourceRatio &gt;= 1.0f)
 {
 //landscape
 resizeRatio = destinationBounds.Width / sourceBounds.Width;
 scaleWidth = destinationBounds.Width;
 scaleHeight = sourceBounds.Height * resizeRatio;
 float trimValue = destinationBounds.Height - scaleHeight;
 graph.DrawImage(source, 0, (trimValue / 2), destinationBounds.Width, scaleHeight);
 }
 else
 {
 //portrait
 resizeRatio = destinationBounds.Height/sourceBounds.Height;
 scaleWidth = sourceBounds.Width * resizeRatio;
 scaleHeight = destinationBounds.Height;
 float trimValue = destinationBounds.Width - scaleWidth;
 graph.DrawImage(source, (trimValue / 2), 0, scaleWidth, destinationBounds.Height);
 }

 return destinationImage;

 }
</code></pre>

Note the <code>InterpolationMode.HighQualityBicubic</code> -> this is generally a good tradeoff between performance and results.

blocks|key|1488103|text|使用这个库：http://imageresizing.net|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1488104|阅读这篇由库作者撰写的文章：20+Image+Sizing+Pitfalls+with+.NET|1488105|entityMap|0|LINK|mutability|MUTABLE|url|http://imageresizing.net/|1|http://nathanaeljones.com/163/20-image-resizing-pitfalls/^0|6|O|0|0|E|Y|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@$A|Q|B|R|1|S]]|C|$]]|$1|D|3|E|5|6|7|T|8|@]|9|@$A|U|B|V|1|W]]|C|$]]|$1|F|3|-4|5|6|7|X|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]|N|$5|I|J|K|C|$L|O]]]]

Use this library: <a href="http://imageresizing.net" rel="noreferrer">http://imageresizing.net</a>

Have a read of this article by the library author: <a href="http://nathanaeljones.com/163/20-image-resizing-pitfalls/" rel="noreferrer">20 Image Sizing Pitfalls with .NET</a>

blocks|key|1703269|text|你可以试试the+magic+kernel。它在放大时比双三次重采样产生的像素化伪影更少，并且在缩小时也能提供非常好的结果。源代码可以在c#的网站上找到。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1703270|entityMap|0|LINK|mutability|MUTABLE|url|http://johncostella.webs.com/magic/^0|5|G|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

You could try <a href="http://johncostella.webs.com/magic/" rel="nofollow">the magic kernel</a>. It produces less pixelation artifacts than bicubic resample when upscaling and it also gives very good results when downscaling.
The source code is available in c# from the web site.

blocks|key|1488222|text|试试这个基本的代码片段：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1488223|private+static+Bitmap+ResizeBitmap(Bitmap+srcbmp,+int+width,+int+height+)
{
++++Bitmap+newimage+=+new+Bitmap(width,+height);
++++using+(Graphics+g+=+Graphics.FromImage(newimage))
+++++++++++g.DrawImage(srcbmp,+0,+0,+width,+height);
++++return+newimage;
}|code-block|syntax|javascript|1488224|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try This basic code snippet:

<pre><code>private static Bitmap ResizeBitmap(Bitmap srcbmp, int width, int height )
{
 Bitmap newimage = new Bitmap(width, height);
 using (Graphics g = Graphics.FromImage(newimage))
 g.DrawImage(srcbmp, 0, 0, width, height);
 return newimage;
}
</code></pre>

blocks|key|1488263|text|我对琼斯博士的回答有一些改进。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1488264|它适用于那些想要按比例调整图像大小的人。它对我进行了测试并发挥了作用。|1488265|我添加的类的方法：|1488266|public+static+System.Drawing.Bitmap+ResizeImage(System.Drawing.Image+image,+Size+size)
{
++++return+ResizeImage(image,+size.Width,+size.Height);
}


public+static+Size+GetProportionedSize(Image+image,+int+maxWidth,+int+maxHeight,+bool+withProportion)
{
++++if+(withProportion)
++++{
++++++++double+sourceWidth+=+image.Width;
++++++++double+sourceHeight+=+image.Height;

++++++++if+(sourceWidth+<+maxWidth+&&+sourceHeight+<+maxHeight)
++++++++{
++++++++++++maxWidth+=+(int)sourceWidth;
++++++++++++maxHeight+=+(int)sourceHeight;
++++++++}
++++++++else
++++++++{
++++++++++++double+aspect+=+sourceHeight+/+sourceWidth;

++++++++++++if+(sourceWidth+<+sourceHeight)
++++++++++++{
++++++++++++++++maxWidth+=+Convert.ToInt32(Math.Round((maxHeight+/+aspect),+0));
++++++++++++}
++++++++++++else
++++++++++++{
++++++++++++++++maxHeight+=+Convert.ToInt32(Math.Round((maxWidth+*+aspect),+0));
++++++++++++}
++++++++}
++++}

++++return+new+Size(maxWidth,+maxHeight);
}|code-block|syntax|javascript|1488267|并根据此代码提供新的使用方法：|1488268|using+(var+resized+=+ImageUtilities.ResizeImage(image,+ImageUtilities.GetProportionedSize(image,+50,+100)))
{
++++ImageUtilities.SaveJpeg(@"C:\myimage.jpeg",+resized,+90);
}|1488269|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|S|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|T|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|V|8|@]|9|@]|A|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I have some improve for Doctor Jones's answer.

It works for who wanted to how to proportional resize the image. It tested and worked for me.

The methods of class I added:

<pre><code>public static System.Drawing.Bitmap ResizeImage(System.Drawing.Image image, Size size)
{
 return ResizeImage(image, size.Width, size.Height);
}


public static Size GetProportionedSize(Image image, int maxWidth, int maxHeight, bool withProportion)
{
 if (withProportion)
 {
 double sourceWidth = image.Width;
 double sourceHeight = image.Height;

 if (sourceWidth &lt; maxWidth &amp;&amp; sourceHeight &lt; maxHeight)
 {
 maxWidth = (int)sourceWidth;
 maxHeight = (int)sourceHeight;
 }
 else
 {
 double aspect = sourceHeight / sourceWidth;

 if (sourceWidth &lt; sourceHeight)
 {
 maxWidth = Convert.ToInt32(Math.Round((maxHeight / aspect), 0));
 }
 else
 {
 maxHeight = Convert.ToInt32(Math.Round((maxWidth * aspect), 0));
 }
 }
 }

 return new Size(maxWidth, maxHeight);
}
</code></pre>

and new available using according to this codes:

<pre><code>using (var resized = ImageUtilities.ResizeImage(image, ImageUtilities.GetProportionedSize(image, 50, 100)))
{
 ImageUtilities.SaveJpeg(@"C:\myimage.jpeg", resized, 90);
}
</code></pre>

I want to scale an image in C# with quality level as good as Photoshop does. Is there any C# image processing library available to do this thing?

High Quality Image Scaling Library

图像处理

我希望在C#中缩放图像的质量级别与Photoshop一样好。有没有可用的C#图像处理库来做这件事？

问高质量图像缩放库
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