如何在WPF下将ImageBrush对象的大图像调整为小尺寸? [英] How to resizing a large image of ImageBrush object to small under WPF?

问题描述

大家好，

我有一个ImageBrush，并在运行时在其ImageSource中设置了较大的图像，因此我想将其调整为较小的图像.
换句话说，图像很大并在运行时加载，实际上我想在WPF设施下将自身大小调整为小图像，而不使用"System.Drawing"命名空间. />
我也使用了这种方法，但是对此我的问题有一个错误:

Hi everybody,

I have an ImageBrush and set an image large in its ImageSource in run-time, so I want resizing it to small image.
In other words, The image is large and loaded it in run-time, actually I want resize (in-place) selfsame to a small image under WPF facilities, don''t use ''System.Drawing'' namespaces.

I also used this method, but it has an error for this my problem:

public static BitmapSource CreateBitmapSourceFromVisual(double width, double height, Visual visual)
{
    if (visual == null)
    {
        return null;
    }
    RenderTargetBitmap bmp = new RenderTargetBitmap((Int32)Math.Ceiling(width), (Int32)Math.Ceiling(height), 300, 300, PixelFormats.Pbgra32);

    bmp.Render(visual);
    return bmp;
}

因为我想像以下程序一样调整myImageBrush的大小:

Because I want resizing the myImageBrush like this program:

myImageBrush.ImageSource = CreateBitmapSourceFromVisual(100, 100, myImageBrush);

任何帮助请...

在此先谢谢您.

Any help pls...

Thanks in advance.

推荐答案

您也应该能够在运行时创建较小的图像.您很可能需要根据需要设置DecodePixelWidth 和DecodePixelHeight .

示例:

http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.bitmapimage.decodepixelheight.aspx [

You should be able to create the smaller image at run time too. You''d most likely need to set DecodePixelWidth and DecodePixelHeight accordingly.

Example:

http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.bitmapimage.decodepixelheight.aspx[^]

使用 ^ ]:

Use Graphics.DrawImage[^]:

public Image Resize(Image i, int w, int h){
 Bitmap r = new Bitmap(w, h);
 Graphics g = Graphics.FromImage(r);
 g.DrawImage(i, 0, 0, w, h);
 g.Dispose();
 return r;
}

请注意，这会产生栅格大小调整，这可能是您想要的缩略图大小.如果您想变得聪明，则必须构造与传递给您的图像相同类型的新图像.但是由于您在示例中使用的是位图，因此在此处执行此操作似乎是合理的.

Note that this produces a raster resize, which is probably what you want for a thumbnail. If you want to be clever you''d have to construct a new image of the same type as the one passed in to you. But since you''re using a bitmap in your example, it seems reasonable to do that here.

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