#--------------------------------------------------------------------
#
#   PyGUI - DrawableContainer - Win32
#
#--------------------------------------------------------------------

from GUI import export
from GUI import Canvas
from GUI.Geometry import rect_topleft, rect_size, offset_rect, empty_rect
from GUI.GDrawableContainers import DrawableContainer as GDrawableContainer
import GUI.GDIPlus as gdi

class DrawableContainer(GDrawableContainer):

    _double_buffer = True
    _win_paint_broken = False

    def update(self):
        self._win.UpdateWindow()

    def with_canvas(self, body):
        win = self._win
        dc = win.GetDC()
        self._win_prepare_dc(dc)
        try:
            canvas = Canvas._from_win_dc(dc)
            body(canvas)
        finally:
            win.ReleaseDC(dc)

    def OnPaint(self):
        if not self._win_paint_broken:
            try:
                win = self._win
                dc, ps = win.BeginPaint()
                try:
                    win_update_rect = ps[2]
                    if not empty_rect(win_update_rect):
                        #print "DrawableContainer.OnPaint: win_update_rect =", win_update_rect ###
                        scroll_offset = self._win_scroll_offset()
                        view_update_rect = offset_rect(win_update_rect, scroll_offset)
                        if self._double_buffer:
                            dx, dy = rect_topleft(view_update_rect)
                            width, height = rect_size(view_update_rect)
                            buffer = gdi.Bitmap(width, height)
                            canvas = Canvas._from_win_image(buffer)
                            canvas.translate(-dx, -dy)
                            self.draw(canvas, view_update_rect)
                            graphics = gdi.Graphics.from_dc(dc)
                            src_rect = (0, 0, width, height)
                            graphics.DrawImage_rr(buffer, win_update_rect, src_rect)
                        else:
                            self._win_prepare_dc(dc)
                            canvas = Canvas._from_win_dc(dc)
                            self.draw(canvas, view_update_rect)
                finally:
                    win.EndPaint(ps)
            except Exception:
                self._win_paint_broken = True
                raise

    def _win_prepare_dc(self, dc):
        dc.SetWindowOrg(self._win_scroll_offset())
    
    def _win_scroll_offset(self):
        return (0, 0)

export(DrawableContainer)