public static WindowsGraphics FromGraphics(Graphics g, ApplyGraphicsProperties properties)
{
Debug.Assert(g != null, "null Graphics object.");
//Debug.Assert( properties != ApplyGraphicsProperties.None, "Consider using other WindowsGraphics constructor if not preserving Graphics properties." );
WindowsRegion wr = null;
float[] elements = null;
Region clipRgn = null;
Matrix worldTransf = null;
if ((properties & ApplyGraphicsProperties.TranslateTransform) != 0 || (properties & ApplyGraphicsProperties.Clipping) != 0)
{
if (g.GetContextInfo() is object[] data && data.Length == 2)
{
clipRgn = data[0] as Region;
worldTransf = data[1] as Matrix;
}
if (worldTransf != null)
{
if ((properties & ApplyGraphicsProperties.TranslateTransform) != 0)
{
elements = worldTransf.Elements;
}
worldTransf.Dispose();
}
if (clipRgn != null)
{
if ((properties & ApplyGraphicsProperties.Clipping) != 0)
{
// We have to create the WindowsRegion and dipose the Region object before locking the Graphics object,
// in case of an unlikely exception before releasing the WindowsRegion, the finalizer will do it for us.
// (no try-finally block since this method is used frequently - perf).
// If the Graphics.Clip has not been set (Region.IsInfinite) we don't need to apply it to the DC.
if (!clipRgn.IsInfinite(g))
{
wr = WindowsRegion.FromRegion(clipRgn, g); // WindowsRegion will take ownership of the hRegion.
}
}
clipRgn.Dispose(); // Disposing the Region object doesn't destroy the hRegion.
}
}
WindowsGraphics wg = WindowsGraphics.FromHdc(g.GetHdc()); // This locks the Graphics object.
wg.graphics = g;
// Apply transform and clip
if (wr != null)
{
using (wr)
{
// If the Graphics object was created from a native DC the actual clipping region is the intersection
// beteween the original DC clip region and the GDI+ one - for display Graphics it is the same as
// Graphics.VisibleClipBounds.
wg.DeviceContext.IntersectClip(wr);
}
}
if (elements != null)
{
// elements (XFORM) = [eM11, eM12, eM21, eM22, eDx, eDy], eDx/eDy specify the translation offset.
wg.DeviceContext.TranslateTransform((int)elements[4], (int)elements[5]);
}
return(wg);
}
