Static controls flicker slightly when the main window changes

Question

INTRODUCTION AND RELATED INFORMATION:

I have a complicated picture to implement in my main WM_PAINT window.

I presented the image below to illustrate this:

The main window has static controls, not buttons with the SS_NOTIFY style.

When the user clicks on them, certain actions take place in the program.

The following figure shows which static controls are in the main window:

The map on the orange panel is an EMF file, the top left and right logos are PNG files, and other images are bitmap images.

To implement this task, I decided to draw the whole picture in WM_PAINT and put invisible static image controls on the image that corresponds to them.

Therefore, I only return NULL_BRUSH in the WM_CTLCOLORSTATIC handler as follows:

 case WM_CTLCOLORSTATIC: return (LRESULT)( (HBRUSH)GetStockObject(NULL_BRUSH) ); 

I am working on Windows XP using the MS Visual Studio C++ 2008 Express Edition and the pure Win32 API .

One note : since Express VS does not have one , the resource editor, resource file and resource header were created using ResEdit from here: http://www.resedit.net/ .

Problem:

When I resize the window, the static controls flicker slightly.

MY EFFORTS TO SOLVE THE PROBLEM:

I processed WM_ERASEBKGND (returned (LRESULT)1 ), and I excluded the CS_VREDRAW and CS_HREDRAW from my window class, so this should not cause flickering.

There is no WS_CLIPCHILDREN style in my window.

EDIT: In response to the comment below, I will explain why this window does not have this style set:

The problem is that part of the desktop image is visible where static controls are installed.

I implemented double buffering for both handlers to avoid flickering.

I used the GDIView tool downloaded here: http://www.nirsoft.net/utils/gdi_handles.html to track the GDI leaks .

Every time I resize the window, GDIView shows +4 in the column for regions, which means that I am leaking regions.

I cannot understand how this is possible, since I do not use APIs that manipulate regions.

To illustrate what I came across, I made a demo application with detailed comments: http://www.filedropper.com/geotermistgrafika

I believe this is a more efficient way and then send the code as it will consume too much space.

Question:

How can I change the code in a demo project to get rid of the flicker?

Is my approach wrong, and if so, which one is right?

Thanks. Best wishes.

Answer 1

When resizing the main window, the WM_SIZE handler moves the static child windows.

When the child window is moved, Windows automatically copies the client area of ​​the child control from the old location to the new location.

The main window will then be repainted into the WM_PAINT handler.

In other words, when the window is resized, all static controls are moved to a new position, and then the rest of the window is redrawn. Lack of synchronization looks like a flicker.

You can avoid this by passing the SWP_NOCOPYBITS flag to SetWindowPos .