public void BeforeRender(RectFloat clipRect)
{
if ((!this.afterRenderCalled || this.beforeRenderCalled) || this.renderCalled)
{
throw new PaintDotNet.InternalErrorException();
}
this.afterRenderCalled = false;
this.beforeRenderCalled = true;
bool flag = this.canvasView.RenderTarget.IsSupported(RenderTargetType.Software, null, null, null);
if (flag || this.IsActive)
{
this.renderStopwatch.Restart();
RectInt32 num2 = RectInt32.Intersect(clipRect.Int32Bound, this.owner.Document.Bounds());
bool flag2 = false;
if (num2.HasPositiveArea)
{
PointInt32 num7;
PointInt32[] array = this.nonCurrentTileOffsets.ToArrayEx <PointInt32>();
this.nonCurrentTileOffsets.Clear();
PointInt32 sourcePt = PointDouble.Round(this.owner.Owner.MouseLocation, MidpointRounding.AwayFromZero);
PointInt32 comparand = this.tileMathHelper.ConvertSourcePointToTileOffset(sourcePt);
CompareTileOffsetsByDistance comparer = new CompareTileOffsetsByDistance(comparand);
ListUtil.Sort <PointInt32, ArrayStruct <PointInt32>, CompareTileOffsetsByDistance>(array.AsStruct <PointInt32>(), comparer);
DequeSet <PointInt32> set = new DequeSet <PointInt32>(array);
int count = set.Count;
while (set.TryDequeue(out num7))
{
if (!this.isDeviceBitmapCurrent[num7.Y][num7.X])
{
if (flag2)
{
this.nonCurrentTileOffsets.TryEnqueue(num7);
}
else
{
if (!this.TryUpdateDeviceBitmap(num7))
{
this.nonCurrentTileOffsets.TryEnqueue(num7);
flag2 = true;
}
if ((!flag2 && !flag) && (this.renderStopwatch.ElapsedMilliseconds > 0x7fffffffffffffffL))
{
flag2 = true;
}
}
}
}
}
}
}