StretchDIBits function

The StretchDIBits function copies the color data for a rectangle of pixels in a DIB, JPEG, or PNG image to the specified destination rectangle. If the destination rectangle is larger than the source rectangle, this function stretches the rows and columns of color data to fit the destination rectangle. If the destination rectangle is smaller than the source rectangle, this function compresses the rows and columns by using the specified raster operation.

Syntax

int StretchDIBits(
  __in  HDC hdc,
  __in  int XDest,
  __in  int YDest,
  __in  int nDestWidth,
  __in  int nDestHeight,
  __in  int XSrc,
  __in  int YSrc,
  __in  int nSrcWidth,
  __in  int nSrcHeight,
  __in  const VOID *lpBits,
  __in  const BITMAPINFO *lpBitsInfo,
  __in  UINT iUsage,
  __in  DWORD dwRop
);

Parameters

hdc [in]

A handle to the destination device context.

XDest [in]

The x-coordinate, in logical units, of the upper-left corner of the destination rectangle.

YDest [in]

The y-coordinate, in logical units, of the upper-left corner of the destination rectangle.

nDestWidth [in]

The width, in logical units, of the destination rectangle.

nDestHeight [in]

The height, in logical units, of the destination rectangle.

XSrc [in]

The x-coordinate, in pixels, of the source rectangle in the image.

YSrc [in]

The y-coordinate, in pixels, of the source rectangle in the image.

nSrcWidth [in]

The width, in pixels, of the source rectangle in the image.

nSrcHeight [in]

The height, in pixels, of the source rectangle in the image.

lpBits [in]

A pointer to the image bits, which are stored as an array of bytes. For more information, see the Remarks section.

lpBitsInfo [in]

A pointer to a BITMAPINFO structure that contains information about the DIB.

iUsage [in]

Specifies whether the bmiColors member of the BITMAPINFO structure was provided and, if so, whether bmiColors contains explicit red, green, blue (RGB) values or indexes. The iUsage parameter must be one of the following values.

Value	Meaning
DIB_PAL_COLORS	The array contains 16-bit indexes into the logical palette of the source device context.
DIB_RGB_COLORS	The color table contains literal RGB values.

 

For more information, see the Remarks section.

dwRop [in]

Specifies how the source pixels, the destination device context's current brush, and the destination pixels are to be combined to form the new image. For more information, see the following Remarks section.

Return value

If the function succeeds, the return value is the number of scan lines copied. Note that this value can be negative for mirrored content.

If the function fails, or no scan lines are copied, the return value is 0.

If the driver cannot support the JPEG or PNG file image passed to StretchDIBits, the function will fail and return GDI_ERROR. If failure does occur, the application must fall back on its own JPEG or PNG support to decompress the image into a bitmap, and then pass the bitmap to StretchDIBits.

Remarks

The origin of a bottom-up DIB is the lower-left corner; the origin of a top-down DIB is the upper-left corner.

StretchDIBits creates a mirror image of a bitmap if the signs of the nSrcWidth and nDestWidth parameters, or if the nSrcHeight and nDestHeight parameters differ. If nSrcWidth and nDestWidth have different signs, the function creates a mirror image of the bitmap along the x-axis. If nSrcHeight and nDestHeight have different signs, the function creates a mirror image of the bitmap along the y-axis.

This function allows a JPEG or PNG image to be passed as the source image. How each parameter is used remains the same, except:

• If the biCompression member of BITMAPINFOHEADER is BI_JPEG or BI_PNG, lpBits points to a buffer containing a JPEG or PNG image, respectively. The biSizeImage member of the BITMAPINFOHEADER structure specifies the size of the buffer. The iUsage parameter must be set to DIB_RGB_COLORS. The dwRop parameter must be set to SRCCOPY.
• To ensure proper metafile spooling while printing, applications must call the CHECKJPEGFORMAT or CHECKPNGFORMAT escape to verify that the printer recognizes the JPEG or PNG image, respectively, before calling StretchDIBits.

ICM: Color management is performed if color management has been enabled with a call to SetICMMode with the iEnableICM parameter set to ICM_ON. If the bitmap specified by lpBitsInfo has a BITMAPV4HEADER that specifies the gamma and endpoints members, or a BITMAPV5HEADER that specifies either the gamma and endpoints members or the profileData and profileSize members, then the call treats the bitmap's pixels as being expressed in the color space described by those members, rather than in the device context's source color space.

Examples

For an example, see Sizing a JPEG or PNG Image.

Requirements

See also

Bitmaps Overview

Bitmap Functions

SetMapMode

SetStretchBltMode

BITMAPINFO

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Build date: 9/7/2011