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2008.10.23 13:44 "Re: JPEGSetupEncode messages", by Bob Friesenhahn
On Wed, 22 Oct 2008, Frank Warmerdam wrote:
>>
>> JPEGSetupEncode: RowsPerStrip must be multiple of 8 for JPEG
>
> I would suggest selecting a RowsPerStrip value that is a multiple
> of 8.
This is the logic I am using in GraphicsMagick:
case COMPRESSION_JPEG:
{
/*
RowsPerStrip must be multiple of 8 for JPEG.
*/
rows_per_strip=rows_per_strip+(8-(rows_per_strip % 8));
(void) TIFFSetField(tiff,TIFFTAG_JPEGQUALITY,image_info->quality);
if (IsRGBColorspace(image->colorspace))
(void) TIFFSetField(tiff,TIFFTAG_JPEGCOLORMODE,JPEGCOLORMODE_RGB);
if (bits_per_sample == 12)
(void) TIFFSetField(tiff,TIFFTAG_JPEGTABLESMODE,JPEGTABLESMODE_QUANT);
break;
}
Bob
======================================
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/