Win32:wm_paint implementation of double buffering slow graph

Related references:

Implement double buffering under GDI-http://jingyan.baidu.com/article/e73e26c0f8df2424acb6a76e.html

<Win32_19> with double buffering technology for a smooth-http://www.myexception.cn/program/1407847.html

Set double buffering to reduce form flicker-Http://hi.baidu.com/robinlxzh/item/ad70a4ae92db5bf614329be7

The usual way to draw without using double buffering on a form:

Case WM_PAINT:

{

Paintstruct PS;

Prepares the drawing work for the specified window and fills in a PAINTSTRUCT structure with information about the drawing.

HDC HDC = BeginPaint (hwnd, &PS);

Hpen Hpen = CreatePen (ps_solid, 1, RGB (128, 128, 128)); Set color

Hpen Hpen = CreatePen (ps_solid, 1, GetSysColor (Color_btnshadow)); 3D Shadow of the button

SelectObject (hdc, hpen);

Rectangle (hdc,-1,-1, 680, 72); Draw a rectangle

DeleteObject (Hpen); Once you no longer need a brush, remember to delete it with the DeleteObject function

Draw Line

Hpen = CreatePen (ps_solid, 1, GetSysColor (Color_btnshadow)); 3D Shadow of the button

SelectObject (hdc, hpen);

MOVETOEX (hdc, 0, 484, NULL); Starting point

LineTo (HDC, 680, 484); End

DeleteObject (Hpen); Once you no longer need a brush, remember to delete it with the DeleteObject function

ReleaseDC (hwnd, HDC); Release

EndPaint (hwnd, &PS); End Slow

return 0;

}

-----------------------------------------------------------------------------

Use the double buffering technique below to draw, compared with the above code, just the original HDC----hdc_old, and then insert the red two parts to implement a double-buffered drawing.

The combination of WM_ERASEBKGND and WM_PAINT:

Case WM_ERASEBKGND:

{

return 1; Avoid heavy brush on window background-Http://hi.baidu.com/robinlxzh/item/ad70a4ae92db5bf614329be7

}

Case WM_PAINT:

{

Paintstruct PS;

Drawing with double buffering technology

Variable: hdc_old represents the system default HDC

Variable: HDC represents a double-buffered memory DC

Prepares the drawing work for the specified window and fills in a PAINTSTRUCT structure with information about the drawing.

HDC Hdc_old = BeginPaint (hwnd, &PS);

Memory DC for Buffering

HDC hdc = CreateCompatibleDC (hdc_old);

Need to get the width and height of the window, ease the size

RECT Clientrect;

GetClientRect (Hwnd,&clientrect);

printf ("width:%d, height:%d\n", clientrect.right,clientrect.bottom);

Create a memory-compatible bitmap hbmp

Hbitmap hbmp = CreateCompatibleBitmap (Hdc_old,clientrect.right,clientrect.bottom);

Select a memory bitmap into the buffer memory DC--so that multiple bitmaps can be drawn

SelectObject (hdc,hbmp);

If you do not perform these two steps, the window will appear with a black background

SelectObject (hdc, Getsyscolorbrush (Color_3dface)); Set Brush color-fill color of Rectangle ()

Since Rectangle () draws a black border line, this is deliberately drawn from -1,-1 +2, +2, so that the black border line beyond the visual range, you can not see

Rectangle (hdc,-1,-1, Clientrect.right + 2, Clientrect.bottom + 2); Draw the entire background of a form

Hpen Hpen = CreatePen (ps_solid, 1, RGB (128, 128, 128)); Set color

Hpen Hpen = CreatePen (ps_solid, 1, GetSysColor (Color_btnshadow)); 3D Shadow of the button

SelectObject (hdc, hpen);

Rectangle (hdc,-1,-1, 680, 72); Draw a rectangle

DeleteObject (Hpen); Once you no longer need a brush, remember to delete it with the DeleteObject function

Draw Line

Hpen = CreatePen (ps_solid, 1, GetSysColor (Color_btnshadow)); 3D Shadow of the button

SelectObject (hdc, hpen);

MOVETOEX (hdc, 0, 484, NULL); Starting point

LineTo (HDC, 680, 484); End

DeleteObject (Hpen); Once you no longer need a brush, remember to delete it with the DeleteObject function

displaying in-memory content to Windows-using the BitBlt function

BitBlt (hdc_old,0,0,clientrect.right,clientrect.bottom,hdc,0,0,srccopy);

Note Reclaim Memory resources

DeleteObject (hbmp);

DELETEDC (HDC);

ReleaseDC (hwnd, HDC); Release

EndPaint (hwnd, &PS); End Slow

return 0;

}

2014-07-03

Win32:wm_paint implementation of double buffering slow graph