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Drawing in a window?

Hi there
I would like to display the contents of a matrix in a window.
if I use code like this:

CClientDC dc;
//do drawing
dc.SetPixel(...);

It works of course, but I do not want to draw directly into the window. Instead I would like to draw to a CDC (i guess) and then blt the contents into the window causing all the changes to happen at once instead of one pixel at a time.

I have tried something like this:

CCLientDC dc;
CDC dcMem;
dcMem.CreateCompatibleDC(&dc);
//do drawing
dcMem.SetPixel(...)
dc.BitBlt(0, 0, Width, Height, &dcMem, 0, 0, SRCCOPY);

but it does not work (no change in the window)

How should I do it?
(maybe creating a bitmap - how?)

Jacob

jacobkristensen

Asked: 2000-02-21

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System Programming

1 Solution

LVL 5

WynCommented: 2000-02-21

The problem is you must select a bitmap into the Memory Device Context.

LVL 5

WynCommented: 2000-02-21

Use the CreateCompatibleBitmap().
Code here:

LVL 5

WynCommented: 2000-02-21

CCLientDC dc;
CDC dcMem;
dcMem.CreateCompatibleDC(&dc);
CBitmap bmp;
bmp.CreateCompatibleBitmap(&dc,1,1);
CBitmap* pOldBmp = dcMem.SelectObject( &bmp );
//do drawing
dcMem.SetPixel(...)
dc.BitBlt(0, 0, Width, Height, &dcMem, 0, 0, SRCCOPY);
dcMem.SelectObject( pOldBmp );
dcMem.DeleteDC();