ChartsOrg/Charts

Chart x offset changes when finished zooming in

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#1,880 opened on Nov 24, 2016

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Description

I'm seeing a weird behavior when I zoom in my charts.

After I end zooming (which means releasing both fingers) the xAxis offset changes as it moves like 20 chart points to the right of where the zoom ended.

The chart is inside another scrollview, but has only vertical scroll. Also this only happens when the zoom level is really close.. not sure exactly when. My code is pretty much the same as the demo.. only a few changes here and there.

Here's a video with the behaviour I'm seeing https://youtu.be/6ZIJmTyuie4 Any idea on why this is happening or how can I fix it?

Contributor guide

Tech stack
swift
Domain
mobile
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.
1-3 hours
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 understanding of iOS developmentFamiliarity with Charts library
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Investigate the zoom mechanism in the Charts library. Look at the source files related to chart scaling and translation, such as ChartViewBase.swift or ChartRenderer.swift. The issue likely involves a calculation error when zooming ends. Check if there are any related PRs or comments that discuss similar behavior. Replicate the issue using the demo code with a scrollview to understand the exact conditions.