Good speed, but graph lines exceed the maximum graph height in charts #1 and #2. This is considered critical.

It's possible to hide line on the chart where it should not be possible. At the same time user can see yellow circle in this state.

Minor issues related to design: insets for buttons, range selection, chart and y-axis lines do not match. View for values has incorrect design too: titles not aligned, value and % symbol have spacing. Arrow looks incorrect. Small chart on background of range selection control has top inset.

Design issues:

1. Dates on the right edge overlap
2. Percentage mini chart doesnt use 100% height
3. theme change button is at the bottom
4. single bar chart shows "all" row and overlaps the cell header
5. percentage tooltip has red indicator
6. Putting tooltip and scaling can remove the tooltip but leave the line with circles (see video)

Issues with landscape mode:
1. buttons overlap
2. charts have dates clipped
3a. second chart right axis labels are in the center
3b. upon return to portrait right axis labels are invisible

— The third graph blinks when filtering.
— The graph preview is incorrect.
— Points for filtered data don't disappear from the graphs (the attached screenshot).
— The 'Night Mode' button is at the very bottom of the page.
— The headers are missing.

Crash on start

Sum of values gives 99%.

Hard 2Y animations. But application is very fast works :)

1. Charts indent is too big
2. axis lines have 100% screen width
3. applying filters on second chart doesnt hide respective axis labels
4. Navigation bar not by design
5. Applying filters on line chart doesnt remove the circles for the tooltip


basically only ui issues, but many

Selection info is drawn under the grid labels.

Bars can stay overlapped with the chart header.

Does not support iOS 8. Telegram does.

maxY on chart has to be on the same position as y-coordinate of the highest y-value by design

wrong minimum

Major issue: filter toggle doesn't not affect y-scaling

values are clipped

After some actions this horizontal separator above the slider shows up. And every time I try to catch it with internal video recording or screenshot, it disappears! Looks like this artefact is related to common work of MTKView and CALayers.

Landscape transition is really bad. I think it is because this app uses Metal.

Critical issue: Poor line quality. It is visible even without zoom. 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. You can read more about line quality in Metal projects in my comments on entry228.

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.

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.

if you drag right side of the slider, you can affect left side too!