Flicker happen in display form when drawing

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I am drawing in a 1024x1024 MFC Form using directx control. 1024X1024 resolution not occupied in my monitor screen, so i enabled scroll bar control for the Display form. I am using thread to draw the form (1024x1024) continuously. At the time i am scrolling to view the hidden part of the display, some flicker is happen. How to avoid that flicker while moving scroll bar in the display.

Posted 26-Mar-13 3:20am

Rajeshkumar Ramasamy

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3 solutions

Solution 1

>I am using thread to draw the form (1024x1024) continuously.
>At the time i am scrolling to view the hidden part of the display, some flicker is happen.

I would not draw the form during scrolling. You can use

SQL

SetRedraw(FALSE)

on the begin and

C++

SetRedraw(TRUE)

on the end of scrolling. Take a look at this example from MSDN:

C++

// Updating a control or window with large amounts of data may cause
// flicker. In such cases it may be better to turn off drawing

//...

   //m_list is a member of type CListCtrl
   m_List.SetRedraw(FALSE);  // turn drawing off regardless of list mode

//...
// Update control
//...

   m_List.SetRedraw(TRUE);  // turn drawing back on and update the window

   // invalidate the entire control, force painting
   m_List.Invalidate();
   m_List.UpdateWindow();

Posted 26-Mar-13 3:32am

Leo Chapiro

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Sergey Alexandrovich Kryukov 26-Mar-13 13:49pm

I'm not sure it will work, without double buffering. Imagine that GDI draws a filled rectangle, and something thin on top of it, say, a line. It will flicked on each invalidation, no matter what you do.
Please see Solution 2 and Solution 3.
—SA

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

nv3 · Accepted Answer · 2013-03-26T04:21:00

Instead of painting directly to your control you could create an equally sized memory DC and bitmap and paint into that. Then, when ready, just bitblt the currently visible part to the DC of the control. That has several advantages:

- drawing to a memory bitmap is faster than drawing to the screen
- you don't have to execute your drawing code for every scroll step; instead you draw once the entire control and just bitblt the part that is visible. Your might oven use the window scrolling functions for scrolling and just bitblt the small stripe that became visible in the last scrolls step.

This technique is called double-buffering and is used widely to suppress screen flicker.

Sergey Alexandrovich Kryukov · Accepted Answer · 2013-03-26T07:47:00

Solution 3

The technique of elimination flicker is called "double buffering".

Please see this CodeProject article: Flicker Free Drawing In MFC[^].

See also:
http://forums.codeguru.com/showthread.php?462696-Double-Buffering-MFC[^],
http://www.cs.sjsu.edu/faculty/beeson/courses/cs130/LectureNotes/17-DoubleBuffering/DoubleBuffer.html[^].

—SA

Posted 26-Mar-13 7:47am

Sergey Alexandrovich Kryukov

Comments

nv3 26-Mar-13 14:32pm

As so often you have a couple of very good links in your sleeve, Sergey. I particularly liked the first one. +5

Sergey Alexandrovich Kryukov 26-Mar-13 14:59pm

Thank you.
And I like your expression "in you sleeve". Pretty often, this is exactly the case. Due to all that CodeProject experience, I keep decent set of links handy, in my records... :-)
—SA

Flicker happen in display form when drawing

3 solutions

Solution 1

Solution 2

Solution 3

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Flicker happen in display form when drawing

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Solution 3

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