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Jasc Paint Shop Pro 9... cm vs. in

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crabby3:
This is a continuation of another topic I started with a similar name...  :P  ...but this one has a more accurate header and content.

I use Mousers SC screencap program to grab pics and save them in the PNG format. But when I open them in PSP the Image Dimensions are in metric (milimeters, ppcm) instead of US Standard (inches, ppi).

Obviously this question is aimed at other users of this Great Classic Program and any related info on this issue would be appreciated!   :)

BTW  I have these installed too: PSP 9.01 Patch, PSP 9.0.1.1
 

Jibz:
Related:

http://forum.corel.com/EN/viewtopic.php?f=56&t=43896

Looking at a screenshot saved from SSC, it appears to correctly set the pHYs chunk to 96 dpi, perhaps PSP fails to do the proper conversion when loading an image with the unit specifier flag set to meters?

mouser:
perhaps PSP fails to do the proper conversion when loading an image with the unit specifier flag set to meters?
--- End quote ---

wait this is the key part -- are you saying that its possible for the png file to specify whether it is stored in meters?

this is the key part we have been struggling with.  Jibz you sound like you are saying that the SC image says that the file should be viewed as using the "meters" unit.  Is that so?

Jibz:
wait this is the key part -- are you saying that its possible for the png file to specify whether it is stored in meters?
-mouser (March 28, 2012, 08:06 AM)
--- End quote ---

4.2.4.2. pHYs Physical pixel dimensions

The pHYs chunk specifies the intended pixel size or aspect ratio for display of the image. It contains:

   Pixels per unit, X axis: 4 bytes (unsigned integer)
   Pixels per unit, Y axis: 4 bytes (unsigned integer)
   Unit specifier:          1 byte

The following values are defined for the unit specifier:

   0: unit is unknown
   1: unit is the meter

When the unit specifier is 0, the pHYs chunk defines pixel aspect ratio only; the actual size of the pixels remains unspecified.

Conversion note: one inch is equal to exactly 0.0254 meters.
--- End quote ---

So, for PNG files, the pixels per unit are either for "meter" or "unknown". SSC sets the unit to meter (1) and pixels per unit to 3780x3780, which correctly converts to 96 dpi x 96 dpi.

Note that the only proper unit is meter here, there is no option to use inch, and the unknown unit seems to only be useful for specifying an aspect ratio.

crabby3:
Related:

http://forum.corel.com/EN/viewtopic.php?f=56&t=43896

Looking at a screenshot saved from SSC, it appears to correctly set the pHYs chunk to 96 dpi, perhaps PSP fails to do the proper conversion when loading an image with the unit specifier flag set to meters?
-Jibz (March 28, 2012, 07:36 AM)
--- End quote ---

Thanks for your time, Jibz, but I'm not sure I understand your answer.   :huh:   I entered unit specifier flag set to meters? into my browser and found this.  I don't understand much of it... so it may not even apply here.

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