Serious displaying/sharpness issues with iOS

Yesterday I finally got my first Xojo iOS app on my iPhone 6 and my wifes iPhone 5.
But I was a bit (read: a lot) disappointed about the iOSTableView ‘sharpness/smoothness’
What am I talking about - I hear you saying. Read on…

Well, the best way to see what I mean is to make a simple app in both Xojo and Xcode (no worries no coding is needed).
Just add an IUTableView in a view and compile in Xojo and Xcode. Then put both on your iDevice (iPhone, iPad, …).
Now launch the Xcode version on your iDevice and drag the tableview up and down very slowly. Take a good look at the thin lines - you will notice the lines have a very smooth scrolling.
Now launch the Xojo compiled app and do the same. You will notice the thin lines do not scroll smoothly - the lines seems to even disappear for microseconds but it is VERY noticeable. It was so obvious even my wife could see the difference between both and that means a lot - trust me - she doesn’t see a difference between a 30fps and 60fps shooter :slight_smile: -

Now I know Xojo is using the Native Tableview but why on earth is the scrolling so different between both version. I seems that the ‘resolution’ is lower and thats why the thin lines are disappearing when doing slow scrolling.

I think this is cumbersome - really - it makes your iOS app look ‘different’ and not performing very well.

BTW this was tested on two Retina devices (iPhone 6 and iPhone5).

OK, even simpler. It is also noticeable in the iOS emulator. Although the problem isn’t as obvious as on a real device it is still noticeable.

The odd part is that in the emulator it is only visible when you compile for the iPhone 6. For iPhone 5 it seems very smooth.
So I also compared it again on the hardware iPhone 6 and 5. And it is indeed only very worse on the iPhone 6.

If you do the same in Xcode and iOS emulator you will notice it butter smooth on all devices.

This makes me thing Xojo iOS isn’t doing something right for iPhone 6 - but no idea what though.
it would be VERY RECOMMENDED to look at this and if possible fix this.

BTW I think you need Retina display to see this odd behaviour. Don’t think that ‘low’ resolution display can see the difference.

Haven’t got a 27" Retina. Cannot see :wink:

Joke’s apart, you may want to do a bug report with a screen capture, since it shows in the simulator.

I also played today with a beautiful app that lets you capture video of a device through the lightning cable.

No need to screen capture this. It is also noticeable in the iOS Emulator.
I did tests with all iDevices and only iPhone 6 and iPhone 6+ has this issue. All others (including iPads) have smooth scrolling.

Remember, with Xcode it is super smooth with all devices incl. iphone 6 and +

Will add a feedback case asap.

[quote=154148:@Michel Bujardet]I also played today with a beautiful app that lets you capture video of a device through the lightning cable.[/quote]
That is built-in into QuickTime in Yosemite.
File > New Screen recording. In the window that comes up, press the little Down arrow and select your connected iPhone :wink:

Didn’t know that. Thank you for the tip!


You weren’t running the Xojo app in native mode on the other devices which causes performance issues as it is emulating another screen type- remember the right Launch Images which tell iOS that you are native on those devices. You can see this in the included examples- or you can use the included Extras…iOS Utilities…iOSImageMaker to quickly add them to an existing project.

Ok, I know why this is happening.

Although I had added all launch images in my project it seems my Launch images where not good (read: compatible?).
I made them with Pixelmator (as PNG) but the resolution was 2 pixels off (too small).
I tried my project with the default Launch Images provided in the Xojo distribution and it resolved the issue.

Probably because it scaled the view?

Case closed. Thank you Travis for this. I never had found this myself - who had thought a 2 pixel difference can cause this issue.

Yep, iOS is very particular about launch image dimensions- if they’re not right, you aren’t running in native mode :slight_smile: