Develop Reference

EXIF Orientation Issue in Safari Mobile

I have an angular 2 application in production environment that allows you to choose a profile picture. Recently, performing tests with safari mobile, specifically for IOS 13.3.1 version(older) and IOS 13.4.1(new) version. I noticed that the image is shown rotated depending of safari browser version used (I built a stackblitz for this that you can review):
IOS 13.3.1 version(older)
IOS 13.4.1(new)
When I take images from an iPhone's in portrait mode and upload the image to my app it is shown rotated only for IOS 13.3.1 version(older). However, I examined the EXIF ​​meta-information images from each of my devices and found that both images have the same value in the orientation property:
IOS 13.3.1 version(older)
IOS 13.4.1(new)
My question is. Why does the image display change depending on the IOS version, knowing that in both cases the orientation EXIF is the same value (6)?
This is a subject that worries me since I had already solved this problem by rotating the image depending of EXIF orientation value for its correct display (e.g. exif.js have been created to handle this situation by detecting the exif orientation flag), but this problem now appears again with the new version of IOS. What would be an example of code that I can use to make it sustainable over time? Is there not a consensus among the browsers to manage the orientation of the images?
What is the explanation for this illogical behavior?
Thank you so much!

We also stumbled upon this when our mobile suddenly behaved differently and finally find the root cause of this.
Both WebKit (iOS) and Android (Chrome) have just recently changed the default behavior of the image-orientation CSS propterty. While it was none before, it is now from-image. This means: Before, they ignored the EXIF data of an image by default, while they are now using it to auto-correct the image. Which break our own auto-correction based on the exifreader library.
Here are some relevant links:
https://www.fxsitecompat.dev/en-CA/docs/2020/jpeg-images-are-now-rotated-by-default-according-to-exif-data/
https://bugs.webkit.org/show_bug.cgi?id=89052
Funny enough, also the Slack team seems to have run into this:
https://bugzilla.mozilla.org/show_bug.cgi?id=1634180
Fortunately, the author of the exifreader library (who just some weeks later ran into the same problems) also guided me to a way to detect the behavior. You can find his answer here:
https://github.com/mattiasw/ExifReader/issues/99#issuecomment-640217716
I also noticed that Modernizr has a test for this, so I am actually using a custom modernizr build now to detect the browser behavior.

The webkit browser is rotating the images before you upload them based on the EXIF data then it gets applied again by your app. We were able to confirm this on new (81) version of Chrome and Mobile Safari on 13.4. then the app is rotating them further and it gets twisted.

Phonegap scrolling issues on android 5

We are developing an app using Phonegap/Javascript.
Scrolling used to work fine, until we tried the new Android 5.
The page does not scroll down, unless you swipe many times. Then it is stuck in the other position..
Can't find anyone with this problem!
We are using just simple divs with content that is taller than the screen. Works fine on Android <5 or iOS.
Any ideas?

This is what finally solved the problem, along with simplifying properties, etc.:
Hammer.defaults.stop_browser_behavior.touchAction = 'pan-y';
It was an issue with the hammer.js plugin with touchAction property.
This affects some browsers - and apparently also Android 5 (but doesn't affect Android 4.* when using PhoneGap).
Not as simple as it seems, more details here:
https://github.com/hammerjs/hammer.js/wiki/How-to-fix-Chrome-35--and-IE10--scrolling-(touch-action)

PhoneGap: different behavior Simulator vs. Device

Very strange problem:
I've created a small HTML5 canvas game with box2dweb.js.
So far, all my work has been on desktop and today I've decided to move it to the iPhone (which usually consists of wrapping the app in a PhoneGap/Cordova application, change a few settings, and that's it.
The problem is, when I run the app on my desktop browsers (Chrome, Safari) as well as the iPhone and iPad simulators - everything works correctly - but when I actually deploy to my device (iPhone 4S) only some of the pictures show up. In fact, only the player sprite animation plays, and everything else (while still there physically) does not get drawn unless it doesn't have a specific animation (whether it's a sequence of images or just one image).
What seems even more strange, is that only the player entity is being drawn (with animation, too!) but all other entities that have animations are simply not drawn.
I've attached images to show the differences:
My question is - where do I even start debugging this? I tried running the index.html page without the cordova app on the iOS simulator so I could access the debug console, but there were no issues. How is this even possible? I was under the impression that if it worked as a web page, it should work as a PhoneGap app.

Alright, I've solved the problem. It was incredibly simple but hard to find. It's not even a PhoneGap problem:
The game has a level editor, and so it also has a saving/loading mechanism. While I specify all the images as './graphics/image.png', when a level gets deserialized it saves the loaded image's source, and not the original './graphics...' path. So the problem was that I was trying to load local files from my computer to my iPhone. I guess it was a path problem after all...

Pixastic doesn't work properly in Safari

I'm using the Pixastic javascript library to make several images on a webpage grayscale. It works in Chrome and Firefox, but not in Safari. Sometimes it makes a few random images grayscale, and sometimes it doesn't do anything at all.
Here's a test page to demonstrate the problem: http://www.edwards.nl/new/test.html
I'm using Safari 5.1.1 on Mac OSX Lion.
Does anyone know what the problem is? I couldn't find a solution anywhere yet.
Edit: It appears that the canvas elements are created, but the grayscaling part doesn't work.

iPad canvas very bad to zero performance

The javascript library I have created just translates a single picture and zooms it. Touch events and mouse events are used depending on what device.
I ran this javascript code on Firefox (7.0.1), iPhone 3GS (iOS 5.0) and iPhone 4 (iOS 5.0) all with smooth performance, no problem at all.
Then I ran it on iPad 1 (iOS 5.0) with slow performance though zooming and translating the picture works.
Last test was on iPad 2 (iOS 4.3.3) and here I experienced the same slow performance while zooming as iPad 1 but the translating didnt work at all.
I have no clue what this is about, since iPhone is supposed to be alot weaker than an iPad. I would appreciate any help or comments to get me on the right track.
http://pastebin.com/wZ7e77yq
UPDATE
I just ran it on an iPad 2 (iOS 5.0) and it works flawlessly. I also tried iPhone 3GS (iOS 4.2.1) and it didnt work, same as iOS 4.3.3. This means that my application needs iOS 5.0 to run... is it really true you couldnt translate objects before iOS 5.0?
UPDATE2
I just ran it on three different iPad 1s (iOS 5.0) and it doesnt work very good. What is the big difference in between an iPhone 4 and an iPad 1? Specs are almost identical. Also the translate didnt work because the function event.pageY/X doesnt work prior to iOS 5. This was fixed by using event.touches.pageX/Y instead.

Well I was developing a small game for testing canvas performance without any special game framework so I kept it simple because I was writing it by myself. The program did nothing special, just moving a sprite around the screen with different joystick types, such as keyboard and mouse for desktop click, and touch events for iOS. I discovered the following:
Using taps direct on the canvas results in poor performance compared to touch events.
Touch events worked well with different canvas sizes up to 1024x768.
I didn't try picture zooming, but that should have be fine as well.
event.pageX, event.pageY worked without problems on iPad (iOS5).
I hope that helps.

Seems like perhaps iOS CANVAS support was the issue. iOS5 has full GPU hardware-accelerated CANVAS support, while previous versions supported CANVAS albeit very poorly.
Surprised that it does not work well on iPad 1 even with iOS 5, though. Can you try closing all currently-running apps, close all other browser tabs, and run the test again?