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JPEG and PNG Extensions for Specific Bitmap Functions and Structures

On certain versions of Microsoft Windows, the StretchDIBits and SetDIBitsToDevice functions allow JPEG and PNG images to be passed as the source image to printer devices. This extension is not intended as a means to supply general JPEG and PNG decompression to applications, but rather to allow applications to send JPEG- and PNG-compressed images directly to printers having hardware support for JPEG and PNG images.

The BITMAPINFOHEADER, BITMAPV4HEADER and BITMAPV5HEADER structures are extended to allow specification of biCompression values indicating that the bitmap data is a JPEG or PNG image. These compression values are only valid for SetDIBitsToDevice and StretchDIBits when the hdc parameter specifies a printer device. To support metafile spooling of the printer, the application should not rely on the return value to determine whether the device supports the JPEG or PNG file. The application must issue QUERYESCSUPPORT with the corresponding escape before calling SetDIBitsToDevice and StretchDIBits. If the validation escape fails, the application must then fall back on its own JPEG or PNG support to decompress the image into a bitmap.

 

 

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