WPF多点触控和缩放 [英] WPF Multitouch and zooming

问题描述

大家好，

我有一个问题:

我有几张图像，将它们放到画布上，订阅了事件ManipulationStarting e ManipulationDelta，到目前为止一切顺利.

我正在从这样的代码后面添加图像:

Hello everybody,

I have just a problem:

I have a few images and I put them into a canvas, subscribing the event ManipulationStarting e ManipulationDelta and so far so good.

I'm adding images from code behind like that :

private void CreateAThumbnail()
        {
            // Create an Image control
            Image thumbnailImage = new Image();
            thumbnailImage.Width = 130;
            thumbnailImage.IsManipulationEnabled = true;

            // Create a BitmapImage and sets its DecodePixelWidth and DecodePixelHeight
            BitmapImage bmpImage = new BitmapImage();
            bmpImage.BeginInit();
            bmpImage.UriSource = new Uri("38-determinazione funzionario resp.tif_page001.tif", UriKind.RelativeOrAbsolute);
 
            thumbnailImage.RenderTransform = new MatrixTransform();
            bmpImage.DecodePixelWidth = 200;
            bmpImage.EndInit();

            // Set Source property of Image
            thumbnailImage.Source = bmpImage;
            canvas.Children.Add(thumbnailImage);

        }

如您所见，我创建了一个BitMapImage并以比原始像素少的像素对其进行解码，因此可以节省内存(实际上我应该加载多达50张图像.tif非常沉重).可以，但同时我想放大 可读的图像，因此我尝试将该图像恢复到其原始像素，以便缩放完全可读.但是我做不到直到现在.

如您所见，我尝试将DecodePixelWidth设置为1200nbsp;在image_ManipulationStarting中，但是图像的像素始终为200.

As you can see, I created a BitMapImage and decoded it with less pixels than the original, so I can save memory (in fact I should load as many as 50 images .tif very heavy).When I zoom the image everything is okay but at the same time I'd like to zoom a readable image, so I tried to restore that image to its original pixel so the zooming would be perfectly readable. But I couldn't do  much until now.

as you see, I tried to set DecodePixelWidth to 1200  in the image_ManipulationStarting but the pixel of image is always 200.

代码在这里:

void image_ManipulationStarting(object sender, ManipulationStartingEventArgs e)
{
    var uie = e.OriginalSource as UIElement;
   

    ImageSource imageSource = ((Image) (uie)).Source;
    BitmapImage bmpToAdjust = imageSource as BitmapImage;

    bmpToAdjust.DecodePixelWidth = 1200;

    //canvas is the parent of the image starting the manipulation;
    //Container does not have to be parent, but that is the most common scenario
    e.ManipulationContainer = canvas;
    e.Handled = true; 
               
}

任何建议将不胜感激！谢谢

Any suggestion would be appreciated! Thanks.

Domenico Mustara

Domenico Mustara

推荐答案

穆斯塔拉，

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祝你有美好的一天.

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