axis tick labels are not properly shown in some cases

eclipse / swtchart

Eclipse Public License 2.0

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axis tick labels are not properly shown in some cases #375

Closed yoshitaka1008 closed 1 month ago

yoshitaka1008 commented 10 months ago

I have seen two cases where axis tick labels are not properly shown.

case 1: when setting axis range containing zero, axis tick label "0" is not shown.

actual: actual_1 expected (before the fix for #124): expected_1

Note: the issue is reproducible with Test1.java in test.zip

case 2: when setting axis tick label format, duplicated tick labels are shown.

actual: actual_2

expected (before the fix for #124): expected_2

Note: the issue is reproducible with Test2.java in test.zip

yoshitaka1008 commented 10 months ago

Analysis and possible solution:

With the fix of #214, the logic to determine whether axis tick label is a major one to display was changed.
I assume the intention of fix was to accept a certain diff between actual tick value and value of tick label display so that tick labels can be shown even when value of tick label display is rounded with axis tick format using IAxisTick.setFormat().
The diff was evaluated by abs((actualTickValue - valueOfTickLabelDisplay / actualTickValue).
But the issue of this approach is that, when actualTickValue becomes larger (e.g. showing range of 10000 to 10000.3), the diff is evaluated smaller.
A possible better approach would be to evaluate the diff based on pixels in display.

yoshitaka1008 commented 10 months ago

Hi @MatthewKhouzam , does the patch 375.patch work in your case?

yoshitaka1008 commented 10 months ago

patch with tests: 375_fix_with_tests.patch

eselmeister commented 10 months ago

@yoshitaka1008 Thanks for your patches. I will also test them.

MatthewKhouzam commented 10 months ago

This is fine here. Thanks for checking!

ghost commented 10 months ago

There is a jar file with the patch?

eselmeister commented 10 months ago

@yoshitaka1008 @MatthewKhouzam Thanks for your feedback. @VictorRojasGIT Wait for the next run of https://ci.eclipse.org/swtchart/job/build/job/develop/. Jars are available after successful build on: https://download.eclipse.org/swtchart/integration/develop/repository or build it yourself via Maven/Tycho.

eselmeister commented 1 month ago

The "0" label issue was already solved.

Screenshot from 2024-09-02 19-34-14

The "duplicated tick labels" was introduced on purpose. But it's true that it might be confusing if no value is displayed at all.

eselmeister commented 1 month ago

Screenshot from 2024-09-02 19-38-05

eselmeister commented 1 month ago

The user defines the tick decimal format. It's almost impossible to deduct a more fine grained decimal format as the decimal format may have been set on purposes. To display that it's not a chart defect, three dots are set instead of hiding the label.