"Beginner" on wrote...
| Hi,
|
| I have been using the ping method to return the size of a TIFF file.
| This size though, seems to be the size of the file on disk. The TIFFs
| I have been looking at had used LZW compression so the actually size
| of the raw image is larger than the disk size.
|
| Is there a way to retrieve the un-compressed file size from a file,
| hopefully as quickly as the ping method? Or is there a formula for
| working out the un-compressed size of a file; width x height x no.
| channel x bits per channel perhaps?
|
You can always get a good idea of a images uncompressed size by using...
width * height * bit_depth/8 * number_of_channels
The number of channels in an image is either 3 for RGB or 4 for RGBA
This is the base size so to make it more accurate you will also need to
add the images profile_size (hightly variable, unless striped) and a
roughly constant header size.
This is only rough but much more accurate than file size.
The -ping test is basically to try and do a minimal read on the image to
get basic information, nothing more. File size is basic information.
Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]>
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And then you turn the corner, as the Dungeon Master chuckles...
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Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
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