public void Draw(IViewport view, Graphics canvas)
{
// This object is readonly.
Debug.Assert(view != null, "It is necessary to have viewport to draw!");
Debug.Assert(canvas != null, "It is necessary to have canvas to draw!");
if (viewport.Equals(view))
{
canvas.DrawImage(data, new Point(0, 0));
}
else
{
var x1 = Math.Max(view.LeftCorner, viewport.LeftCorner);
var x2 = Math.Min(view.RightCorner, viewport.RightCorner);
var y1 = Math.Max(view.BottomCorner, viewport.BottomCorner);
var y2 = Math.Min(view.TopCorner, viewport.TopCorner);
if ((x1 < x2) && (y1 < y2))
{
// Image is at least partly on the screen.
var destLeft = view.XToCanvasX(x1);
var destTop = view.YToCanvasY(y2);
var srcLeft = viewport.XToCanvasX(x1);
var srcTop = viewport.YToCanvasY(y2);
canvas.DrawImage(data,
new Rectangle(destLeft, destTop, view.XToCanvasX(x2) - destLeft,
view.YToCanvasY(y1) - destTop),
new Rectangle(srcLeft, srcTop, viewport.XToCanvasX(x2) - srcLeft,
viewport.YToCanvasY(y1) - srcTop), GraphicsUnit.Pixel);
}
}
}