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2006.08.25 05:40 "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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