Trying to change PNG Checksum Value with no experience - png

I apologies in advance if any of my terminology is wrong or used incorrectly.
I am trying to edit a PNG image that is part of a program that requires a CRC-32 checksum in order to function. I have looked online about how to change the value but my lack of programing knowledge prevents me from making any progress. Could someone possibly help me change the value back to the correct one after I have edited the PNG image please?

Related

How to make a .bmp file (some hex data) display as a qr-code

I am a college student dealing with some file problems.
I have saved a .bmp file which I knew it should be a qr-code.
Instead, it displayed as a meaningless picture.
Example meaningless picture
I'm wondering what's might be happening and what can I do ?
Thanks.
Huh. First, welcome to SO.
Second, your question needs clarification. How do you get this file (maybe it's auto-generated or something)? Can you ask for another one and see if it's meaningless too?
File definetely looks corrupted, but I'm not sure if it's due to creation error or some kind of saving/network/whatever malfunction.
Also, your question is possibly off-topic and you ought to address it to https://superuser.com/ instead.

modify a template PDF using iTextSharp server side

So I'm brand spanking new to iTextSharp and I know I have quite a bit of reading ahead of me but in an attempt to shave a bunch of time off a relatively trivial task I thought I reach out the stack brain-trust.
I have a very simple goal: Starting with a template pdf, I need to create new pdf with a few of the characters changed. We're talking single characters on each page. I don't need a detailed answer complete with code (although that'd be awesome) so much as a general list of tools and api's I'm going to need.
The data I need will already be in a db which I could output to xml files if need be.
So far it looks like my template will need the "editable" characters tagged somehow (not sure how to do that yet) and using PDFStamper I can modify the copy. Is that the right path or is there a better way?
Thanks for any insight.

VB to download torrent, deflate gzipped section selectively

Apologies if this is a basic question, i'm a very casual programmer.
I'm writing a program which will search for torrents, grab them based on certain criteria (one being that they are indicated as freeware, you'll be pleased to hear) and then throw them over to utorrent. I'm getting stuck downloading the .torrent file, because, I believe, of the encoding.
I've worked out thus far that the bulk of the top of the file can be gzip deflated on the fly using HTTPrequest - but it seems that half-way through the file, something changes - and looking in a hex editor at a .torrent i've grabbed from a site directly versus the one I download here, everything is identical up to a point, then all is totally different.
If i'm being vague i'm afraid it's because i'm making this all up as I go along! Is it likely that the encoding / compression in a torrent file would change part way through, and how could I catch this in VB to avoid corrupting the latter half?
Thanks very much in advance,
Dan

How does one add custom metadata tags to an image on the iPhone?

I tried adding custom entries in the exif dictionaries I received from an image. This didn't work. I'm assuming this is due to the fact exif is a standard that is already defined.
Basically I am trying to create a metadata tag that can be placed in jpegs that will have no character limit.
I read that XMP metadata tags do not have character limits. Is this true? If so how would I create these on the iPhone?
Thank you.
I'm not sure what you've all tried code wise, but Caffeinated Cocoa has a pretty good blog entry on Image Metadata that I've used in an application for a client a while ago that might help you.
Also, the SO post Problem setting exif data for an image looks like it references the Caffeinated Cocoa. Although this question is a little over a year old, it still might help.
Try giving these a shot.

Exif and iPhone files

Im using a library for extracting EXIF data from google code.
I assume with iPhone OS 3 that you can use UIImagepicker to do it.
I just want to be able to extract the f-Stop, Shutter Speed and ISO data from the image.
I want to discard the image and just use the information that I store up.
Would I end up extracting the tag data in the viewcontroller.m or h?
This part of coding seems to baffle me a little bit and I cant figure out what to put where.
Can anyone help me out? I still havent figured out XCode all that well.
Whatever executable code you have needs to go in a .m (implementation) file, not a .h (header file). The headers are just for declaring things like classes, protocols, and methods, not for any real processing work.
Are there any tutorials that you know of that explain using exif step by step?
im using the one found here -
http://iphone-land.blogspot.com/2008/06/geo-tagging-images-using-iphone-exif.html
However, for a newbie like me, its not all that thorough because im coming up with errors and i am not sure how to resolve them.
I guess im just shy in all this. need a good place to start
You will likely have trouble getting access to an images metadata if you get it via UIImagePickerController, due to the issues described in this question: UIImagePickerController and extracting EXIF data from existing photos