SetPixelFormat function (wingdi.h)

Article
02/22/2024

The SetPixelFormat function sets the pixel format of the specified device context to the format specified by the iPixelFormat index.

Syntax

BOOL SetPixelFormat(
  HDC                         hdc,
  int                         format,
  const PIXELFORMATDESCRIPTOR *ppfd
);

Parameters

hdc

Specifies the device context whose pixel format the function attempts to set.

format

Index that identifies the pixel format to set. The various pixel formats supported by a device context are identified by one-based indexes.

ppfd

Pointer to a PIXELFORMATDESCRIPTOR structure that contains the logical pixel format specification. The system's metafile component uses this structure to record the logical pixel format specification. The structure has no other effect upon the behavior of the SetPixelFormat function.

Return value

If the function succeeds, the return value is TRUE.

If the function fails, the return value is FALSE. To get extended error information, call GetLastError.

Remarks

If hdc references a window, calling the SetPixelFormat function also changes the pixel format of the window. Setting the pixel format of a window more than once can lead to significant complications for the Window Manager and for multithread applications, so it is not allowed. An application can only set the pixel format of a window one time. Once a window's pixel format is set, it cannot be changed.

You should select a pixel format in the device context before calling the wglCreateContext function. The wglCreateContext function creates a rendering context for drawing on the device in the selected pixel format of the device context.

An OpenGL window has its own pixel format. Because of this, only device contexts retrieved for the client area of an OpenGL window are allowed to draw into the window. As a result, an OpenGL window should be created with the WS_CLIPCHILDREN and WS_CLIPSIBLINGS styles. Additionally, the window class attribute should not include the CS_PARENTDC style.

Examples

The following code example shows SetPixelFormat usage.

PIXELFORMATDESCRIPTOR pfd = { 
    sizeof(PIXELFORMATDESCRIPTOR),   // size of this pfd  
    1,                     // version number  
    PFD_DRAW_TO_WINDOW |   // support window  
    PFD_SUPPORT_OPENGL |   // support OpenGL  
    PFD_DOUBLEBUFFER,      // double buffered  
    PFD_TYPE_RGBA,         // RGBA type  
    24,                    // 24-bit color depth  
    0, 0, 0, 0, 0, 0,      // color bits ignored  
    0,                     // no alpha buffer  
    0,                     // shift bit ignored  
    0,                     // no accumulation buffer  
    0, 0, 0, 0,            // accum bits ignored  
    32,                    // 32-bit z-buffer  
    0,                     // no stencil buffer  
    0,                     // no auxiliary buffer  
    PFD_MAIN_PLANE,        // main layer  
    0,                     // reserved  
    0, 0, 0                // layer masks ignored  
}; 
HDC  hdc; 
int  iPixelFormat; 
 
// get the best available match of pixel format for the device context   
iPixelFormat = ChoosePixelFormat(hdc, &pfd); 
 
// make that the pixel format of the device context  
SetPixelFormat(hdc, iPixelFormat, &pfd);

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	wingdi.h
Library	Gdi32.lib
DLL	Gdi32.dll

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