Re: pnoJpegLib - Now with encoding

[Miguel Angel Sotomayor Hernandez]

I downloaded the library and started using it. I think I could help with 
the documentation (examples storing images to VFS or something like 
that) if I can make it work.

I'm facing a problem but since I've never used it before I'm not sure if 
I'm doing something wrong. I want to store an image to a sd card but the 
file is 0 bytes length. I get the bitmap from the treo's camera and then 
I try to save it and then I display the image. Everything works fine and 
there is no error while storing the image. The bitmap is properly 
displayed. Here is what I do to store the image (only part of the code, 
relevant to the pnoJpegLibrary, the complete function is below):

err = pnoJpeg2EncodeCreate(pnoJpegRefNum, &jpegEncode);
   if(err == errNone){
           pnoJpeg2EncodeToVFS(pnoJpegRefNum, jpegEncode, volRefNum, path);
           pnoJpeg2EncodeSetQuality(pnoJpegRefNum, jpegEncode, 50);
           pnoJpeg2EncodeProgressive(pnoJpegRefNum, jpegEncode, true);
           err = pnoJpeg2Write(pnoJpegRefNum, jpegEncode, bitmapP);
           pnoJpeg2EncodeFree(pnoJpegRefNum, &jpegEncode);
}
am I doing it right? what am I missing? I hope you can point me to the 
right direction.

Here is how I get the bitmap, how I get the VFS ref, how I store the 
image and how I display it. The only problem is with the resulting file 
(0 bytes).

BitmapType  * bitmapP;
bitmapP = BmpCreate (previewWidth, previewHeight, previewDepth, 0, &err);
UInt16       * bits;
bits = (UInt16 *) BmpGetBits (bitmapP);
        
for (i = 0; i < previewWidth * previewHeight; i++)
           bits[i] = 0x07e0;
        
err = CameraLibPreview (gLibRefNum, bits, kCameraImageFormatRGB16, 
previewWidth, previewHeight);
if(!err){
   pnoJpeg2EncPtr jpegEncode;
   UInt16 volRefNum;
   UInt32 volIterator;
   Char path[64];
   UInt16 pathLength;
   FileRef fr;
   Err err=0;
   Err error=0;

   volIterator = vfsIteratorStart;
   pathLength = 64;
   error = VFSVolumeEnumerate(&volRefNum, &volIterator);
   if (error == errNone)
   error = VFSGetDefaultDirectory(volRefNum, ".jpg", path, &pathLength);
   else
   DisplayError("VFS Error", error);
   if (error == errNone)
   {
   if (pathLength > 0 && path[pathLength - 1] == '\0')
           pathLength--;
   if (pathLength > 0 && path[pathLength - 1] != '/')
           path[pathLength++] = '/';
   StrNCopy(path + pathLength, "image.jpg", 64 - pathLength);
   error = VFSFileOpen(volRefNum, path, vfsModeCreate | 
vfsModeReadWrite, &fr);
   }else
   DisplayError("Error reading default directory", error);
   if (error == errNone){
   err = pnoJpeg2EncodeCreate(pnoJpegRefNum, &jpegEncode);
   if(err == errNone){
           pnoJpeg2EncodeToVFS(pnoJpegRefNum, jpegEncode, volRefNum, path);
           pnoJpeg2EncodeSetQuality(pnoJpegRefNum, jpegEncode, 50);
           pnoJpeg2EncodeProgressive(pnoJpegRefNum, jpegEncode, true);
           err = pnoJpeg2Write(pnoJpegRefNum, jpegEncode, bitmapP);
           pnoJpeg2EncodeFree(pnoJpegRefNum, &jpegEncode);
   }

   }else
   DisplayError("Error openning file", error);
   if(err != errNone)
   DisplayError("Error saving image", error);
   if(err == errNone) {
   // Now do what you want with the JPEG-Data MemHandleFree(hJpeg);
   }
   WinDrawBitmap (bitmapP, previewLeft, previewTop);
}
I hope you can help me, I can't find any other source of documentation 
(I switched from Yves Piguet's jpeg library because It's better documented).
Thanks in advance.

Stefan Stolz wrote:
Hi together,
finally i've got the time to complete the pnoJpegLib. Now it's possible
to encode 16-Bit Bitmaps into Jpeg-Files.
Also, a bug which caused a crash when loading progressive JPEGs is fixed.
Best regards
Stefan Stolz
---
pnoJpegLib: http://www.bin-people.de/pnoJpegLib/
 

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