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Testing and Issues

You can test this app and submit issues during the testing period of the iOS Chart contest.

Install .ipa files via AltStore

Entries with serious issues will not be able to win the contest, but even minor issues might be important for overall results.


by rating


Incorrect design implementation (scrollbar, dates). Impossible to tap and hold to view a series of consecutive data points. Good speed overall.
iPhone 6 Plus, iOS 12.1
Inconsistent tooltip behavior:
Apparently it moves around to not cover y values
... but not always
iphone6 12.1.4
Keen Seal Apr 21, 2019 at 08:37
Looked at the code and found a bug. I’ve introduced a minimal height for stack chart so even small data is visible to user, but that broke up sum Y calculations.
Impossible to put tooltip on the edge points
iphone6 12.1.4
big issue with trimmer:
1. Hard to start scrolling when the range is minimum, although the minimum range is pretty big
2. When u manage to start, it starts jumping and not smooth.
iphone6 12.1.4
Keen Seal Apr 21, 2019 at 08:39
Ugh, AutoLayout got me on this. Doing UI is so hard
Sergey Dikovitsky Apr 17, 2019 at 20:08
View with values and range selector have incorrect colors in day mode.
iPhone 5s / iOS 12.2
Sergey Dikovitsky Apr 17, 2019 at 20:09
Single bar chart has no y-axis labels
iPhone 5s / iOS 12.2
Keen Seal Apr 18, 2019 at 15:51
What are the reproduction steps? I can't see it on my iPhone 5S
Sergey Dikovitsky Apr 17, 2019 at 20:11
Strange animation on bar chart.
iPhone 5s / iOS 12.2
Keen Seal Apr 18, 2019 at 17:45
That's because red and blue filters have too big gap in terms of values. I just had no time to polish it, other filters work fine
Fair Quokka Apr 27, 2019 at 20:33
— The app is laggy when filtering the third graph.
— The app suports iOS 11+ only. 
iPhone 6s, iOS 12.0.2
During fast scrolling and scaling there are no y-value labels at all. Not only the UX is suffering, but also it may give this contestant a HUGE advantage in performance over other participants.
Sergey Dikovitsky Apr 17, 2019 at 20:09
Circles for selected values have incorrect color.
iPhone 5s / iOS 12.2
Keen Seal Apr 18, 2019 at 17:43
Uh, yeah, I just liked how they looked and decided to skipped making them gray inside, but should've done it, of course
ios 12.0 min - really? :(
Keen Seal Apr 18, 2019 at 13:49
Are you sure? It should be 11.3, that's not the minimum but this is what I was able to test
Incorrect status bar color. Incorrect indicator color
IPhone 6s, iOS 12.2
Keen Seal Apr 18, 2019 at 17:36
Colors were reported earlier, I don't think it is worth to mention it twice
No labels - no problems :D until change interval
IPhone 6s, iOS 12.2
Keen Seal Apr 18, 2019 at 17:38
This is actually a feature I've invested quite some time into. If you will run animation on every tick when finger movement cause min max to invalidation you will show a ton of labels into user's face, so instead I track if min/max is stable enough to run Y label animation.

Moreover, if you move the slider and minmax don't change, then Y label stay in place and no animation occurs.

I don't think it can be considered an issue.
Incorrect highlight in day mode
IPhone 6s, iOS 12.2
Strange random opacity on date labels when scrolling
iphone 6 12.1.4
inconsistent animation durations on the UI elements on theme change
+ wrong color of "all" row on stacked bar
+ wrong mask
iphone6 12.1.4
Keen Seal Apr 21, 2019 at 08:38
I think that’s the third time colors are mentioned
Regarding issue number 2.
Reproduction steps are:
1. Launch the app
2. scroll to the single bar chart

Result: no y axes until u scale/scroll
iphone6 12.1.4
Keen Seal Apr 21, 2019 at 08:35
Uh, really can’t reproduce it on iPhone 5s, iPhone 8Plus and iPhone X. Sad! Thanks for the screen cast
1. Long tap is not working on percentage chart (only there)
2. Everywhere you can hide all series except one. On percentage chart minimum is 2.

-> again inconsistent
iphone6 12.1.4
Keen Seal Apr 21, 2019 at 08:35
Well, as you can probably guess, that’s done on purpose. I agree it may be inconsistent, but allowing to filter down to 1 is basically the same that allow deselect everything on other charts - user will only see colored screen.

I personally don’t think this is an issue.
All issues in one:
1) Y label animation is very wrong.
2) design is very different with requirements.
3) selected value highlight on bar charts highlight also white area at the top.
4) First/last x labels show not first/last dates.
5) X label opacity animations are wrong.
6) Night mode change animation is buggy (colors change differently for grid, navigation bar or table bg)
7) Lots of weird animations.
iPhone SE
Does not support iOS 8. Telegram does.
Major issue: does not support iOS 10.
Critical issue: does not support iOS 11.
Keen Seal Apr 24, 2019 at 13:50
Okay I got it
maxY on chart has to be on the same position as y-coordinate of the highest y-value by design
Keen Seal Apr 24, 2019 at 16:04
Can you elaborate? I don't see any problem with minimum
can't slide with finger on date selection
Keen Seal Apr 24, 2019 at 16:05
What does it mean?
Sometimes you have this strange vertical white line on the right, sometimes you don't
There should be white space to the left and to the right when you select the whole range
Critical issue: Line joints are not rounded, even on iPhone X. So, it's not some minor optimization for old devices, rounded joints implementation on Metal require a lot more math to implement, a lot more vertices to calculate for each frame and 2-3 times more polygons to draw.
Keen Seal Apr 24, 2019 at 13:50
No, there are easier ways to achieve that, but the approach I took looks nice to me

Adding rounded corners is no way hard to implement
Critical issue: This code uses Metal and it will never work on 32-bit devices (including iPhone 5 on iOS 10.3).
Major issue: It's not so easy to port this code to iOS 8 on iPhone 5S either, because he uses help classes from MetalKit (otherwise he would support iOS 8). And you have to do a lot more work without it.
Keen Seal Apr 24, 2019 at 16:03
No, it actually is. MetalKit is not the reason 11.3 is the minimal version
Date labels flicker on every slider movement. Look at this video, here I didn't release my finger from the slider.
can't start new filter toggle while previous one is animating
can't leave just one item in area chart
Keen Seal Apr 24, 2019 at 13:53
It was reported earlier and obviously done on purpose.
Critical issue: line drawing quality is poor. It is not easy to implement good line quality on bare Metal, MSAA is not enough. Qualitative line drawing requires a lot more calculations and tricks. And such implementations may still be worse than Core Animation / Core Graphics quality and would definitely affect the performance.
Look at lines quality comparison, 4x zoom (1st screenshot is from entry 228, 2nd - from my app using CAShapeLayer).
Keen Seal Apr 24, 2019 at 16:00
It actually is, but just does not worth it. I think current quality is more than acceptable and more smooth line quality can be achieved in a couple of hours
More about line drawing quality. In stage 1 I used Metal too and faced many issues in line drawing quality. I wasn't satisfied until I found a technique that showed almost undistinguishable results on edges and joints (rounded, yes) from CoreAnimation. But nobody else among Metal participants paid attention to this problem - and that's sad. 
Objectively speaking, it's not fair to compare apps with so different lines quality.
Nobody added any issues yet...