How to uncompress .PNG graphics files in app bundle

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Level 1

66 points

How to uncompress .PNG graphics files in app bundle

Is there a utility or application code that will allow me to uncompress or uncompile the .PNG images in a myApp.app bundle?

Apparently XCode or something else can compress compile or alter the .PNG files so that what is in the app bundle (when extracted) is no longer readable as a .PNG file by the quicktime, preview or other graphic applications. However, If I include the files as-is in another application, including in a .xib file, then once the new application is compiled, the images are usable, and appear just fine.

I would like to decompress or decompile theses somehow so that I can manipulate the images, use their size and shape information (which is unrecognized in their current state) for layouts in Interface Builder and other graphics programs. My extracted .jpg and .gif files do not suffer from this problem.

Is there a utility that can do this, or can XCode do it?

Help! Thanks!

PB Ti G4 1Gh 10.5.7 768M, 15" iMac G4 800Mh 10.3.9 768M DM9 1.6Gh 10.5.7 2G, Mac OS X (10.5.7)

Posted on Aug 30, 2009 1:52 PM

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Answer 1

reststop Author

Level 1

66 points

Aug 30, 2009 6:16 PM in response to reststop

Answering my own question again...

It seems that the compression is more a transformation to make it faster to load and draw if you are using UIKit routines for your PNG graphics. Further explanation and information on how to convert back to regular PNG format can be found at http://modmyi.com/wiki/index.php/IphonePNGimages

Answer found thanks to google and finding the right selective keywords (XCode PNG).

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Answer 2

K T

Level 7

23,895 points

Aug 30, 2009 2:30 PM in response to reststop

If you have the originals, use them. If you're trying to re-use images from someone else's app, ask them for the originals. If you re-use someone else's images, be aware they or Apple can tag you if they decide something was used without permission.

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Answer 3

reststop Author

Level 1

66 points

Aug 30, 2009 3:28 PM in response to K T

Hi K T,

Unfortunately, the images I'm talking about are from an app I'm trying to port to the iPhone and the original author is no longer contactable by his 1991-2000 contact information. Thus, I don't have access to the originals, if they still exist. I collaborated with the author years ago on some of this. I can recreate them from scratch, if I have to, but since I have an app bundle containing the files, it would be so much easier if I could decompress them and work with the original data.

For other images, I have been able to use screen shots which I then edited by hand, and that took several days of work in Photoshop. I can do without, but I figure if there is a utility, or other programmatic way then I will learn something and be that much farther ahead on getting the program re-released.

Thank you for the awareness about using other images. I don't usually use other people's images without making changes to better suit my purpose. In this case, I am trying to have the first release be a recreation of the "classic" version, and want to be as true to the original images as I can.

What I find interesting is that NOT ALL of the .PNG files are unreadable as-is.

-Carl

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