测试打印机是否支持 JPEG 或 PNG

SetDIBitsToDevice 函数使用 DIB 中的颜色数据来设置设备上与目标设备上下文关联的指定矩形中的像素。

SetDIBitsToDevice 已扩展，允许 JPEG 或 PNG 映像作为源映像传递。

例如：

// 
// pvJpgImage points to a buffer containing the JPEG image 
// nJpgImageSize is the size of the buffer 
// ulJpgWidth is the width of the JPEG image 
// ulJpgHeight is the height of the JPEG image 
// 

// 
// Check if CHECKJPEGFORMAT is supported (device has JPEG support) 
// and use it to verify that device can handle the JPEG image. 
// 

ul = CHECKJPEGFORMAT;

if (
    // Check if CHECKJPEGFORMAT exists: 

    (ExtEscape(hdc, QUERYESCSUPPORT,
               sizeof(ul), &ul, 0, 0) > 0) &&

    // Check if CHECKJPEGFORMAT executed without error: 

    (ExtEscape(hdc, CHECKJPEGFORMAT,
               pvJpgImage, nJpgImageSize, sizeof(ul), &ul) > 0) &&

    // Check status code returned by CHECKJPEGFORMAT: 

    (ul == 1)
   )
{
    // 
    // Initialize the BITMAPINFO. 
    // 

    memset(&bmi, 0, sizeof(bmi));
    bmi.bmiHeader.biSize        = sizeof(BITMAPINFOHEADER);
    bmi.bmiHeader.biWidth       = ulJpgWidth;
    bmi.bmiHeader.biHeight      = -ulJpgHeight; // top-down image 
    bmi.bmiHeader.biPlanes      = 1;
    bmi.bmiHeader.biBitCount    = 0;
    bmi.bmiHeader.biCompression = BI_JPEG;
    bmi.bmiHeader.biSizeImage   = nJpgImageSize;

    // 
    // Do the SetDIBitsToDevice. 
    // 

    iRet = SetDIBitsToDevice(hdc,
                             ulDstX, ulDstY,
                             ulDstWidth, ulDstHeight,
                             0, 0,
                             0, ulJpgHeight,
                             pvJpgImage,
                             &bmi,
                             DIB_RGB_COLORS);

    if (iRet == GDI_ERROR)
        return FALSE;
}
else
{
    // 
    // Decompress image into a DIB and call SetDIBitsToDevice  
    // with the DIB instead. 
    // 
}