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TIFF and LibTiff Mail List Archive

Thread

2006.08.25 05:40 "[Tiff] How to find/read resolution values of TIFF image file", by muthu kumar
2006.08.25 05:56 "Re: [Tiff] How to find/read resolution values of TIFF image file", by Toby Thain
2006.08.29 14:02 "Re: [Tiff] How to find/read resolution values", by muthu kumar
2006.08.29 15:32 "Re: [Tiff] How to find/read resolution values", by Joris

2006.08.25 05:40 "[Tiff] How to find/read resolution values of TIFF image file", by muthu kumar

Dear Friends,

I am new to Tiff file processing.

I can read the tiff file and i used the functions to assign the resolution of the image as follows,

uint32 w,h,bpp, xres=0, yres=0, resunit=2;

TIFFSetField(tiff,TIFFTAG_RESOLUTIONUNIT,(uint16)resunit);

TIFFSetField(tiff,TIFFTAG_XRESOLUTION,(float)xres);

TIFFSetField(tiff,TIFFTAG_YRESOLUTION,(float)yres);

and it works well. But when i tried to read the resolution using the functions

uint32 w,h,bpp,xres=0, yres=0, resunit=0;

TIFFGetField(tiff, TIFFTAG_XRESOLUTION, &xres);

TIFFGetField(tiff, TIFFTAG_YRESOLUTION, &yres);

TIFFGetField(tiff, TIFFTAG_RESOLUTIONUNIT, &resunit);

I got the results like

   xres = 0x42900000 or   xres = 0x43960000 

I know that the
    xres = 0x42900000 for dpi = 72
and xres = 0x43960000 for dpi = 300

But I want to know how to calculate the dpi values from this hex values. Is there any fomula for this. Or the function i am using is wrong.

Please help.

Thankyou.

Muthu.J

muthupyr@yahoo.com

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