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How to draw into memDC, then show it

I would like to:
1. memDC.LineTo(60,60)
2. Determine the extension of memDC
3. draw memDC to my window screen

Is this possible without using bitmap?

If bitmap is needed to use, now I can
handle it but must first determine the
extension of bitmap first, then draw on
memDC. But I want to first draw on
memDC, then create a bitmap with the
correct needed extension, then draw
bitmap on window.

Please write sample code.
I use VisualStudio 6, MFC, c++

Thanks, Tomas

tko092397

ASKER

Edited text of question.

migel

Hi!
You can not transwer data from one DC to another without bitmaps.

When you use memoryDC
You must before create bitmap with required dims. select it into thebmemory context? draw into the context, BitBlt from memory context to the destination context and then select memory context old bitmap back.
for example:
{
CDC dcDisplay;
dcDisplay.CreateIC("DISPLAY", "", "", NULL)
CDC dcMem;
dcMem.CreateCompatibleDC(NULL);
CBitmap bm;
bm.CreateCompatibleBitmap(&dcDisplay,100,100 );
CBitmap* pbmOld = dcMem.SelectObject(&bm);
/* drawing routines here width using dcMem */
dcDest.BitBlt(...); //dcDest is the DC where to your image will be transfered
dcMem.SelectObject(pbmOld);
dcDisplay.DeleteDC();

}

Zoppo

Hi tko,

perhaps you'd prefer drawing to a metafile in memory and than draw this metafile to your dc. For this see help for CreateMetaFile, CloseMetaFile and CDC::PlayMetaFile()

ZOPPO

chensu

A memory DC without a bitmap selected into it can't be used for drawing.

ASKER CERTIFIED SOLUTION

jclanz

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tko092397

ASKER

Thanks!!

Tomas