Blank screen using DrawImage method

问题:

I have to draw a bitmap image using DrawingContext.DrawImage method.

Using the code below everything is working correctly:

BitmapImage myImage = new BitmapImage(); myImage.BeginInit(); myImage.UriSource = new Uri("image.png", UriKind.Relative); myImage.EndInit();  Rect area = new Rect(new Size(myImage.PixelWidth, myImage.PixelHeight)); DrawingVisual myVisual = new DrawingVisual();  using (DrawingContext context = myVisual.RenderOpen()) { context.DrawImage(myImage, area); } 

But only if the image does not exceed 2Mb about, i.e. the area (myImage.PixelWidth x myImage.PixelHeight) is not larger than 10000x10000. In this case the screen remains blank and no any exception is thrown (so I can not tell if there was an error).

How could I fix this problem? Thanks.

回答1:

Looks like larger images aren't yet loaded when you render them. Try the following to load the bitmap:

BitmapSource myImage = BitmapFrame.Create(     new Uri("image.png"),     BitmapCreateOptions.None,     BitmapCacheOption.OnLoad); 

Or this desperate attempt:

using (Stream fileStream = new FileStream("image.png", FileMode.Open)) {     BitmapSource myImage = BitmapFrame.Create(         fileStream, BitmapCreateOptions.None, BitmapCacheOption.OnLoad); } 

文章来源: Blank screen using DrawImage method