[ACCEPTED]-How to render a WPF UserControl to a bitmap without creating a window-graphics
Accepted answer
Have you tried spinning up an instance of 3 the user control and doing something like 2 this:
UserControl control = new UserControl1();
control.Measure(new Size(300, 300));
control.Arrange(new Rect(new Size(300,300)));
RenderTargetBitmap bmp = new RenderTargetBitmap(300, 300, 96, 96, PixelFormats.Pbgra32);
bmp.Render(control);
var encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bmp));
using (Stream stm = File.Create(@"c:\test.png"))
encoder.Save(stm);
It looks like you need to Measure, Arrange. This 1 worked for me.
Ended up using an HwndHost with no actual 1 window.
void cwind()
{
Application myapp = new Application();
mrenderer = new WPFRenderer();
mrenderer.Width = 256;
mrenderer.Height = 256;
HwndSourceParameters myparms = new HwndSourceParameters();
HwndSource msrc = new HwndSource(myparms);
myparms.HwndSourceHook = new HwndSourceHook(ApplicationMessageFilter);
msrc.RootVisual = mrenderer;
myapp.Run();
}
static IntPtr ApplicationMessageFilter(
IntPtr hwnd, int message, IntPtr wParam, IntPtr lParam, ref bool handled)
{
return IntPtr.Zero;
}
Apparently, if you call control.UpdateLayout() after measuring 2 and arranging, the user control doesn't 1 need to be in any window.
Based on IDWMaster's solution I did it a 4 bit differently using the System.Windows.Forms.UserControl. Otherwise the 3 bindings were not up-to-date when the export 2 to bitmap happened. This works for me (this is 1 the WPF control to render):
System.Windows.Forms.UserControl controlContainer = new System.Windows.Forms.UserControl();
controlContainer.Width = width;
controlContainer.Height = height;
controlContainer.Load += delegate(object sender, EventArgs e)
{
this.Dispatcher.BeginInvoke((Action)delegate
{
using (FileStream fs = new FileStream(path, FileMode.Create))
{
RenderTargetBitmap bmp = new RenderTargetBitmap(width, height, 96, 96, PixelFormats.Pbgra32);
bmp.Render(this);
BitmapEncoder encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bmp));
encoder.Save(fs);
controlContainer.Dispose();
}
}, DispatcherPriority.Background);
};
controlContainer.Controls.Add(new ElementHost() { Child = this, Dock = System.Windows.Forms.DockStyle.Fill });
IntPtr handle = controlContainer.Handle;
Source:
stackoverflow.com
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