Graphics平移原點及向上向右方向爲正方式變換

Image img = Image.FromFile(path);
using (var g = Graphics.FromImage(img))
{
	g.Transform = new System.Drawing.Drawing2D.Matrix(1, 0, 0, -1, 0, 0);//Y軸向上爲正，X向右爲正
	g.TranslateTransform(ox, oy, System.Drawing.Drawing2D.MatrixOrder.Append);//平移座標原點
}