ChartsOrg/Charts

CombinedChartView: First and last bars are shown half only

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#2105 opened on Jan 22, 2017

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bughelp wanted★★★

Description

I migrated my existing code to Charts 3.0.1 now and have some issues with the combined chart view (bars and lines).

After the straight forward migration my diagram looks as shown in the following picture. bildschirmfoto 2017-01-22 um 11 21 01

When I add the following lines of code in order to show the bars completely the xAxis values gets corrupted completely.

combChart.xAxis.granularityEnabled = true
combChart.xAxis.granularity        = 1.0
combChart.xAxis.spaceMin           = 0.5
combChart.xAxis.spaceMax           = 0.5
combChart.xAxis.valueFormatter     = self

bildschirmfoto 2017-01-22 um 11 23 47

The Strings for the xAxis values are drawn with the following lines of code.

public func stringForValue(_ value: Double, axis: AxisBase?) -> String
    {
        if Int(value) < _xValues.count {
            return _xValues[Int(value)]
        } else {
            return ""
        }
    }

I checked the output the stringForValuefunction. But the function gets called exactly 4 times and returns the correct Strings:

2017.01.22 11:23:43.460 [DEBUG] [DiagramCombinedCollectionViewCell stringForValue(_:axis:)](417): xValue: 0.000000 1. Serie
2017.01.22 11:23:43.461 [DEBUG] [DiagramCombinedCollectionViewCell stringForValue(_:axis:)](417): xValue: 1.000000 2. Serie
2017.01.22 11:23:43.462 [DEBUG] [DiagramCombinedCollectionViewCell stringForValue(_:axis:)](417): xValue: 2.000000 3. Serie
2017.01.22 11:23:43.463 [DEBUG] [DiagramCombinedCollectionViewCell stringForValue(_:axis:)](417): xValue: 3.000000 4. Serie

Any idea whats going wrong? Or do I forget to set any relevant axis parameter?

Contributor guide

Tech stack
swift
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Basic knowledge of Charts libraryUnderstanding of xAxis configuration
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
The issue describes that first and last bars are cut in half when using CombinedChartView. The user attempted to use granularity and spaceMin/spaceMax but it corrupted xAxis labels. To fix, examine the axis rendering logic in Charts, specifically the BarChartRenderer and CombinedChartRenderer. Check the xAxis space handling and how bar positions are calculated. Review the current implementation of xAxis.spaceMin and spaceMax to ensure they correctly offset the bars without affecting label formatter. Also, verify that the granularity setting does not interfere with the index based label formatter.