Freeze hDC

[Lance Edmonds]

Unless you create a bitmap and select it into the DC, the DC has no size... the bitmap specifies the 'boundary' (for lack of a better word) of the DC.

From WIN32.HLP:

CreateCompatibleDC:
Before an application can use a memory device context for drawing operations, it must select a bitmap of the correct width and height into the device context. Once a bitmap has been selected, the device context can be used to prepare images that will be copied to the screen or printed.

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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Semen Matusovski]

Jules --
I see in this sample

memdc = CreateCompatibleDC(hdc)
hbit = CreateCompatibleBitmap(hdc, maxX, maxY)
SelectObject memdc, hbit

This way I know and it's works.
I am surprised that it's necessary to create dummy bitmap, because in my code I execute BitBlt hdc -> hdcMem in any case.


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[Jules Marchildon]

semen, this will answer your questions.

creating a virtual window for supercharged repaints.

[url]http://l]

hth
jules

[Semen Matusovski]

Lance --
I understood idea. Thanks.

One probem. It looks that in any case I should
CreateCompatibleBitMap and select it into CreateCompatibleDC
Is it so ?

[This message has been edited by Semen Matusovski (edited April 07, 2000).]

[Lance Edmonds]

I gather you want to eliminate the "flicker"?

The best way if to use a "hidden DC" and then just BltBit() it to the window during %WM_PAINT.

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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Semen Matusovski]

Inside WM_PAINT I try to execute two covering each other TextOut
(big font).
I use different colors and it's visible blinking during a short time.
Is it possible to "freeze" hDC from GetDC up to ReleaseDC ?