Swift – Create PNG or JPG from UIImage (not for saving locally)

Oops. Original answer was specific to a similar question. This has been revised:

var canvas = document.getElementById("mycanvas");
var img    = canvas.toDataURL("image/png");

with the value in IMG you can write it out as a new Image like so:

document.write('<img src="'+img+'"/>');

Turn if off and then on again.

Seriously, restart the device — that’s what fixed it for me.

Here’s what didn’t work:

• Cleaning DerivedData
• Cleaning the project
• Uninstalling the app from the device
• Restarting Xcode
• Restarting the computer

Older observations:

Just like the others, it:

• Works fine in the Simulator
• Used to work on the devices (iPhone 5S, iPad Air)
• No code changes (verified via git reset --hard HEAD), yet stopped working.

What I remember triggering the first build where it stopped working was unplugging the iPhone while it was runnning. (Not sure if it’s related.)

However, the git reset not fixing it (combined with all the clean steps not working) tells me it this must be getting cached somewhere else. Quite possibly in one of the .gitignored files? (I’m using Git ignore file for Xcode projects)

One workaround that worked for one UIImageView (in the UIView that has three) but not for the others was putting the image into an .xcassets file. Reverting to the plain image file did not undo the fix. (Really feels like a caching error.)

UPDATE: See top — restarting the device is what fixed it. I get the feeling the wrong bitmap data is being cached on the device itself.

Radar: http://openradar.appspot.com/23534818