void OnDrawAreaRedraw(object sender, RedrawEventArgs e)
{
if (redraw_backbuffer)
{
if (!RedrawBackbuffer(e.Painter))
{
return; //no active drawing
}
screen_dirty = new Rectangle2i(0, 0, backbuffer.Width - 1, backbuffer.Height - 1); //entire screen is now dirty
}
RedrawOverlay();
}
void RedrawOverlay()
{
Drawing drw = CurrentDrawing;
if (drw == null || backbuffer == null)
{
return; //no overlay if no drawing
}
//Point2i dcs = cursorpixel;
Point2d cursor_wcs = CursorWorldPos;
//make sure overlay area is as big as backbuffer
if (overlay == null || overlay.Width < backbuffer.Width || overlay.Height < backbuffer.Height)
{
if (overlay != null)
{
overlay.Dispose();
}
overlay = Guppy.CreatePicture(backbuffer.Width, backbuffer.Height, PictureMode.Software);
}
using (PainterExtentsRecorder exrec = new PainterExtentsRecorder()) //to remember area drawn to
{
using (Painter overlaypainter = overlay.CreatePainter())
{
if (overlay_needs_background)
{
overlaypainter.Blit(backbuffer, 0, 0, backbuffer.Width, backbuffer.Height, 0, 0, backbuffer.Width, backbuffer.Height);
overlay_needs_background = false;
}
using (PainterAggregate painter = new PainterAggregate(overlaypainter, exrec))
{
//let the current sink do its job
painter.Transform = CurrentDrawing.ViewTransform;
CurrentSink.OnTracking(cursorpixel, cursor_wcs, painter);
}
Rectangle2i fliprect = Rectangle2i.Empty; //the part of screen to flip
Rectangle2i newdirtyrect = fliprect; //the new dirty screen rectangle
//compute slightly grown extents of area to show
var er = exrec.RecordedExtents;
if (!er.Empty)
{
newdirtyrect = new Rectangle2i((int)(er.XMin - 5), (int)(er.YMin - 5), (int)(er.XMax + 5), (int)(er.YMax + 5));
fliprect = newdirtyrect;
}
//include old dirty area in flipping rectangle
if (!screen_dirty.IsEmpty)
{
fliprect = fliprect.Append(screen_dirty.XMin, screen_dirty.YMin);
fliprect = fliprect.Append(screen_dirty.XMax, screen_dirty.YMax);
}
//flip if fliprect not empty.
if (!fliprect.IsEmpty)
{
using (Painter frontpainter = drawarea.CreatePainter())
{
int x = fliprect.XMin, y = fliprect.YMin, w = fliprect.Width, h = fliprect.Height;
frontpainter.Blit(overlay, x, y, w, h, x, y, w, h);
overlaypainter.Blit(backbuffer, x, y, w, h, x, y, w, h);
}
}
//remove the temp graphics from the overlay buffer
if (!screen_dirty.IsEmpty)
{
int x = screen_dirty.XMin, y = screen_dirty.YMin, w = screen_dirty.Width, h = screen_dirty.Height;
overlaypainter.Color = RGB.Green;
}
screen_dirty = newdirtyrect;
}
}
}