private void RenderThreadFunc()
{
lock (this)
{
_activeRequest = null;
if (_pendingRequest != null)
{
_activeRequest = _pendingRequest;
_pendingRequest = null;
}
}
if (_activeRequest != null)
{
try
{
// Return null if no update required
BitmapSource result = Dispatcher.HasShutdownStarted ? null : (BitmapSource)RenderFrame(_activeRequest.Visible, _activeRequest.Output, _activeRequest);
if (result != null)
{
Dispatcher.BeginInvoke(
new RenderCompletionHandler(OnRenderCompleted),
new RenderResult(_activeRequest, result));
}
}
catch (Exception exc)
{
Trace.WriteLine(string.Format("RenderRequest {0} failed: {1}", _activeRequest.RequestID, exc.Message));
}
}
}
protected virtual void OnRenderCompleted(RenderResult result)
{
if (result.IsSuccess)
{
_completedRequest = result.Request;
_completedBitmap = result.Bitmap;
_bitmapInvalidated = false;
InvalidateVisual();
BackgroundRenderer.RaiseRenderingFinished(this);
}
}
private void CreateRenderTask(DataRect visible, Rect output)
{
lock (this)
{
_bitmapInvalidated = true;
if (_activeRequest != null)
{
_activeRequest.Cancel();
}
_pendingRequest = new RenderRequest(_nextRequestId++, visible, output);
_renderAction.InvokeAction(RenderThreadFunc);
}
}
/// <summary>Constructs successul rendering result</summary>
/// <param name="request">Source request</param>
/// <param name="result">Rendered bitmap</param>
public RenderResult(RenderRequest request, BitmapSource result)
{
_request = request;
_source = result;
}
protected abstract BitmapSource RenderFrame(DataRect visible, Rect output, RenderRequest renderRequest);