WPF Canvas生成图片的时候，我想把分辨率改成300，怎么做？代码 见内

[Jonney]

public void ExportToBmp(Uri path, Canvas surface)
{
if (path == null) return;

Transform transform = surface.LayoutTransform;
surface.LayoutTransform = null;

Size size = new Size(surface.Width, surface.Height);
surface.Measure(size);
surface.Arrange(new Rect(size));

RenderTargetBitmap renderBitmap =
new RenderTargetBitmap(
(int)size.Width,
(int)size.Height,
96d, //这个地方就是输出分辨率的设置，我把这两个96改成300，输出的图片就不完整，为什么 ？
96d,
PixelFormats.Default);
renderBitmap.Render(surface);

using (FileStream outStream = new FileStream(path.LocalPath, FileMode.Create))
{
BmpBitmapEncoder encoder = new BmpBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(renderBitmap));
encoder.Save(outStream);
}
surface.LayoutTransform = transform;
}

[jiaoshiyao]

Bitmap

[dongxy14]

WriteableBitmap