Sorry your browser is not supported!

You are using an outdated browser that does not support modern web technologies, in order to use this site please update to a new browser.

Browsers supported include Chrome, FireFox, Safari, Opera, Internet Explorer 10+ or Microsoft Edge.

Newcomers DBPro Corner / Catching an error

Author
Message
sberk
14
Years of Service
User Offline
Joined: 6th Jun 2010
Location: next to a cup of coffee
Posted: 25th Jul 2011 19:30 Edited at: 26th Jul 2011 00:53
Link
Hi,
I'm trying to catch a runtime error. I'm loading an image using the following code:
.
However, if the file is damaged my program crashes. Is there any way to use something along try... catch ... like vb.net?
Back to top
Profile PM
=PRoF=
21
Years of Service
User Offline
Joined: 17th Mar 2003
Location: Milton Keynes, UK
Posted: 27th Jul 2011 11:28
Link
Sadly not. It would be a great addition to DBP's language.

You could possibly load the image into a memblock, validate it as an actual working image there before converting the memblock to image with the make image from memblock command. Altho I have no idea how you would go about the actual checking.


Bitmap Font Creator Alpha Out Now!
Back to top
Profile PM Email Website
sberk
14
Years of Service
User Offline
Joined: 6th Jun 2010
Location: next to a cup of coffee
Posted: 27th Jul 2011 11:31
Link
mmm.... sounds pretty complicated. You would have to implement the whole jpg-standard (if you limit it to jpgs) on your own.
Back to top
Profile PM
Grog Grueslayer
Valued Member
19
Years of Service
User Offline
Joined: 30th May 2005
Playing: Green Hell
Posted: 28th Jul 2011 04:18 Edited at: 28th Jul 2011 04:54
Link
Do you have a damaged pic we can test this problem with or would a file renamed to .jpg or .png do the same?

Edit: I decided to create a pre-checker for .jpg files for you. It requires IanMs Matrix 1 Utilities Plugin so if you don't have it nows your chance to be one of the cool kids.

IanMs Matrix 1 Utilities Plugin Direct Download:
https://forumfiles.thegamecreators.com/download/2192430

What the following code does it checks for the .jpg identifier that's 6 bytes into all .jpgs. If the .jpg doesn't have "JFIF" at that specific spot it's not a true .jpg. This of course won't help if the .jpg is damaged beyond the "JFIF" identifier.



Back to top
Profile PM Email
sberk
14
Years of Service
User Offline
Joined: 6th Jun 2010
Location: next to a cup of coffee
Posted: 28th Jul 2011 10:17
Link
Hi,
your solution won't help. The picture was a jpg, but it was damaged during downloading (the last bytes were missing). I used

which reports whether the download was successfully started, but not successfully finished. At the moment I just check after downloading whether the file size is correct, to prevent this specific mistake.

However, I can't guarantee that the server reports always the correct size. Therfore I just wanted to make sure the programm didn't crash.
I have attached a sample pic.

sberk

PS: Since I'm not sure whether I have all necessary rights to upload the original picture I used one from wiki commons and created the same probleme.
http://commons.wikimedia.org/wiki/File:Black-tailed_gull.jpg?uselang=en
I'm not the photographer of this picture, it was me, Bamse, and all license details can be found there.
PPS: just to make it clear, the wiki picture is correct, the attached picture is the destroyed one

Attachments

Login to view attachments
Back to top
Profile PM
Back to top

Login to post a reply

Server time is: 2024-11-24 02:34:44
Your offset time is: 2024-11-24 02:34:44