When saving a bmp file on the iphone, is the file being manipulated ?

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When saving a bmp file on the iphone, is the file being manipulated ?

Hi, i've searched the forum, the net and documentation and couldn't find the answer-

When i save a bmp file to my iphone photos library, for example, when downloading it from a web or from an email, is the BMP file being manipulated to another form when it is saved on the iphone file system ?
my application deals with BMP files (among others). in my application flow, a user will choose a BMP image from the photo library (an image he previously put there as described before) and the application will need to use this image's BMP data AND i MUST be sure that the BMP file data did not change at all since the time it was stored in the photo library until my application retrieved it.

would really appreciate an answer,
thanks a lot.

imac, Mac OS X (10.5.7)

Posted on Jul 15, 2009 12:41 PM

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Answer 1

Jul 15, 2009 2:34 PM in response to nkobik

I can't imagine why you'd need or want to work with BMP files, but couldn't you determine whether or not they were being altered yourself with a simple checksum after each round trip?

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Answer 2

nkobik Author

Level 1

5 points

Jul 16, 2009 12:12 AM in response to Bang A. Lore

Hi,
Thanks,

The reason i work with BMP is that part of my app algorithm is an old and working C code which does what i need over a BMP file. Implementing that code in objective-c might be too much of an overhead for me.

You're right about the test. i'll do it ASAP.

Does anybody know if there's a simple way or what is the most simple way to write a PNG file to my Documents directory (app sandbox) as a BMP ? and i mean a real BMP image file.. a one i can actually open with some preview application.
assuming that a user chose a PNG image from the photo library (i'm using UIImagePickerControl), i recieve the image as UIImage* (to the userFinishedPickingImageithInfo ) in my app and i would like to write the selected image as a pure BMP file to my Documents dir.

thanks !

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Answer 3

K T

Level 7

23,889 points

Jul 16, 2009 9:21 AM in response to nkobik

BMP is not a supported iPhone file format. You would have to convert it before bringing it onboard and after taking it back down.

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Answer 4

Jul 16, 2009 9:25 PM in response to K T

Actually bmp and a number of surprising formats are supported according the iPhone Programming Guide. However this seems to only be for reading. I don't know of any built in functions except for PNG and JPG and the photo album seems deal only in JPEGS.

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Answer 5

K T

Level 7

23,889 points

Jul 16, 2009 10:33 PM in response to Scott Squires1

Scott Squires1 wrote:
Actually bmp (clip...) seems to only be for reading.

Yep, and thanks for the followup.

'supported' was assumed to be beyond read only according to the op's needs as I understood them - sorry if I misread those.

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