Comments on: Resize a UIImage the right way

By: Lucas

Lucas — Sat, 24 Jul 2010 02:30:13 +0000

Simply fabulous. I replaced my current thumbnail generation method with this much better one! I was in need of a simple way to save the image with rounded edges so that the table didn’t have to call the .layer method for every single cell (and create major lag) and this did the trick! Thanks!!

By: Christopher Cotton

Christopher Cotton — Fri, 16 Jul 2010 17:05:21 +0000

Using the code, I added in the ability to do automatic hires scaling for the iPhone 4. This makes the images show up nicer when on the iPhone 4.

http://gist.github.com/478626

One thing I haven’t tested yet, is making sure it works when the original is of Scale 2.0. I will test it soon. But it works great with other images.

By: Erik

Erik — Sat, 03 Jul 2010 03:41:16 +0000

…and I’m an idiot. I’d like to thank everybody for not making fun of me.

By: Erik

Erik — Wed, 30 Jun 2010 06:05:41 +0000

Fantastic code. A really useful method you should consider adding is resizing an image with a maximum dimension. If either the width or height of the image exceeds the specified max, it gets resized without altering the aspect ratio. If the image does not exceed the specified max, it does not get resized.

By: Erik

Erik — Tue, 29 Jun 2010 21:55:18 +0000

Yes, same issue here. A 24bit PNG with alpha when resized appears blank. XCode 3.2.3 here

By: Paul

Paul — Sun, 27 Jun 2010 13:09:22 +0000

Firstly, thanks for the sharing this code.

I’m using this library to crop and then resize an image, then upload it to a site. The REALLY weird thing is it starts off 1536×2048 (623kb) and AFTER cropping and resizing it is 1000×1000 BUT (965kb)

Sorry but I am really confused. I’m trying to shrink the file to limit the amount of data sent and it just seems to be getting bigger.

Any one else had similar problems, or have any suggestions?

Thanks.

By: Fahad

Fahad — Mon, 07 Jun 2010 13:24:23 +0000

Hello,

Thank you for sharing the code, I’m not sure how to use the extra methods with my code, I want the users to be able to resize the image (without cropping it).

Any help would be much appreciated, Thank you.

By: Marc

Marc — Wed, 26 May 2010 02:33:17 +0000

Trevor,

Please forgive my simple question about the use of this application code. I have an application that is downloading very large images, they consume to much memory to use as is and just stuff into a view. Is it possible to use your code to create an alternate image that retains the same aspect ratio and boundaries so that the image is unchanged, and then save the image to a file for later use

Thanks again

By: Marc

Marc — Wed, 26 May 2010 01:15:43 +0000

Well I thought I knew. Looks just like my daughter when she graduated. closer examination by my kids found that the year on the hat is wrong. Still a real coincidence that the resemblance is so strong. everyone got a laugh.

Thanks for the blog very helpful.

By: Tom (v2.0)

Tom (v2.0) — Fri, 21 May 2010 13:02:08 +0000

Just a little suggestion.

rename hasAlpha to hasSupportedAlpha and remove kCGImageAlphaFirst and kCGImageAlphaLast from the test so the image will be copied into a supported format even if it has an alpha channel if the type is unsupported.

It seems to be working for me but I’m no expert with quartz.