[Customdrawn] VMG. attn Felipe

[Felipe Monteiro de Carvalho]

Ok, now I fixed the screenshot code =) rev 36559

Issues:

1> The ScreenDC is not zero. It is WND=0 which results in the DC
returned by GetDC(0) which will return CDWidgetset.ScreenDC. Each
interface should created a buffered TLazCanvas for ScreenDC
operations. I added some generic code in case the buffered ScreenDC is
not created and a new nice routine IsScreenDC(DC)

2> It was thinking that the DC has always size (100, 100), I fixed that.

The test case for screenshot taking is lazarus/examples/canvas_test
which has a screenshot test.

Nasty bug I just found: It seams that resizing forms with Align <>
alNone crash at least in X11 =(

-- 
Felipe Monteiro de Carvalho