Legacy ImageMagick Discussions Archive

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Zoom_in_on_Image (jpegBuffer, jSize)
{
wand    myWand;
size_t   *image_length;
unsigned char *myBuffer;

  // create wand
   NewWandGenesis ( myWand);
  // copy jpeg to wand
   MagicReadImageFromBlob (myWand, jpegBuffer, jSize);
  // Scale 2x
   MagickMagnifyImage (myWand);
  // get contents of the wand
   myBuffer = MagickGetImageBlob(myWand, &image_length);
  // copy it to the frame buffer memory
   memcpy (frameBuffer, myBuffer,image_length);

  //  Display it in the frame buffer. If I use jpegBuffer it displayes a normal sized image. 
  display_fb (frameBuffer, Dev_0);

Code: Select all

void Zoom_in_on_image (char  *Image_Buffer; private_image_data_t *Image_struct)
{
MagickBooleanType	status;
MagickWand	*magick_wand;
ExceptionInfo           *exception;
ImageInfo               *image_info;
ExceptionType	an_error;
int 		j=0;
size_t		iLen=0, iSize=0;
unsigned char	*IM_Image_Buffer;

// Routine enters with a 
// char * Image_Buffer  ( pointer to the jpeg image)
// and an Image_struct which has data on the image like .img_size, .geometry members
// from an outside encoder 
// The Image structure also has (for the decoder) .data and a .queue members

	iSize = Image_struct.img_size;

	printf("Beginning bytes, byte1=0x%X, byte2=0x%X\n",Image_Buffer[0],Image_Bufferf[1] );
	// *** These bytes are 0xFF and 0xD8 *** which are the right bytes (SOI) for a JPEG

                 printf( "last 2 bytes = [0x%X], [0x%X]\n",Image_Buffer[iSize-2],Image_Buffer[iSize-1] );
	// *** These bytes are 0xFF and 0xD9 *** which are the right bytes (EOI) for a JPEG

               // Start of ImageMagicK code
	MagickWandGenesis ();

	magick_wand = NewMagickWand();
	MagickGetException ( magick_wand, &an_error);
	if (an_error)
		printf( "Error in creating wand\n")

	// Clear wand space
	ClearMagickWand (magick_wand);

	// Tell ImageMagick it is a jpeg 
	MagickSetFormat ( magick_wand, "JPG" );

	// copy image into wand
	// The failure is here ****  Seems to be caught in a loop ***** Never gets past this point. *****
	printf( "At ReadImageBlob\n");
	status = MagickReadImageBlob ( magick_wand, Image_Buffer, iSize);
	MagickGetException ( magick_wand, &an_error);
	if (an_error)
	{
		ExceptionType severity;
  		char *err = MagickGetException(magick_wand, &severity);
		printf( "ImageMagickReadImageBlob Error:[%s]", err);
		MagickRelinquishMemory(err);
	}
	if (status)
	{
  		printf("MagicReadImageBlob returned error=[%d]\n",status);
	}

[ Zoom code goes here, and since I never get past the MagickReadImageBlob, it would be irrelevant ]

	MagickWandTerminus();