Highcharts Flutter: Disable Y-Axis Scrolling and Panning
Disable Y-axis scrolling in Highcharts Flutter. Steps: disable chart panning, set yAxis min/max, use afterSetExtremes to lock extremes, or disable yAxis scrollbar (Highstock).
How to disable Y-axis scrolling in Highcharts Flutter chart? I’ve tried disabling panning and zoom options but the chart still scrolls vertically on the Y-axis. What configuration settings are needed to prevent this unwanted Y-axis movement?
Disabling Y-axis scrolling in Highcharts Flutter requires specific configuration beyond just turning off panning and zoom. You need to either set fixed yAxis min/max values, disable yAxis.scrollbar in Highstock, or implement advanced event handlers to prevent vertical movement. These approaches will effectively lock the Y-axis in place while maintaining other chart functionality.
Contents
- Problem Overview: Unwanted Y-axis Scrolling
- Why Y-axis Scrolling Occurs in Highcharts
- Quick Fix: Disable Panning and Set Fixed yAxis Range
- Highstock Solution: yAxis.scrollbar Configuration
- Advanced: afterSetExtremes Event for Control
- Custom Mouse Wheel Handlers
- Flutter-Specific Implementation Tips
- Example Code and Configuration
- Troubleshooting and FAQs
Problem Overview: Unwanted Y-axis Scrolling
Highcharts Flutter developers often encounter unwanted vertical scrolling on the Y-axis despite disabling chart panning and zoom options. This issue occurs because Highcharts, by default, allows users to scroll and pan along both axes unless explicitly configured otherwise. When implementing charts in a Flutter environment, this vertical movement can be particularly problematic as it disrupts the intended user experience and may cause confusion or misinterpretation of the data visualization.
The root cause lies in how Highcharts handles axis interaction. Even with panning: false and zoomType: null, the yAxis might still respond to touch gestures or mouse wheel events, allowing users to scroll beyond the intended data range. This behavior is especially noticeable in Flutter where touch events are directly translated to chart interactions through the WebView wrapper.
Why Y-axis Scrolling Occurs in Highcharts
Understanding why Y-axis scrolling happens is crucial to effectively disabling it. According to the Highcharts official documentation, scrollbars are enabled per axis and appear when the plot area becomes too narrow or when data visualization requires navigation through large datasets.
In standard Highcharts (non-Stock), the Y-axis typically doesn’t include a scrollbar by default, but it can still respond to panning and wheel events. As noted in the Highcharts forum, “In general, yAxis doesn’t support scrollbar, only xAxis.” However, this doesn’t prevent vertical scrolling - it just means the UI element for scrolling might not be visible.
The key difference between Highcharts and Highstock is that Highstock has built-in support for scrollbars on any axis, including the Y-axis. The Highcharts blog explains: “Upon popular request, we have implemented support for scrollbars on any axis in Highstock 4.2.6.” This implementation makes scrollbar behavior more explicit and configurable in Highstock versions.
Quick Fix: Disable Panning and Set Fixed yAxis Range
The most straightforward solution to prevent Y-axis scrolling in Highcharts Flutter is to set explicit minimum and maximum values for the Y-axis. This approach effectively locks the axis range and prevents any vertical scrolling or panning beyond the defined limits.
In your Highcharts configuration, add the following yAxis settings:
yAxis: {
min: yourMinValue,
max: yourMaxValue,
// Optional: Add startOnTick and endOnTick if you want to include complete data points
startOnTick: false,
endOnTick: false
}
By setting both min and max to specific values, you create a fixed range that users cannot scroll beyond. This method works reliably across all Highcharts versions, including when embedded in Flutter applications.
For example, if your chart displays temperature data ranging from 0 to 100 degrees, your yAxis configuration would look like:
yAxis: {
min: 0,
max: 100,
title: {
text: 'Temperature (°C)'
}
}
This approach ensures that regardless of user interaction, the Y-axis will remain fixed within the specified range, eliminating unwanted vertical scrolling while maintaining full chart functionality for other interactions.
Highstock Solution: yAxis.scrollbar Configuration
If you’re using Highstock in your Flutter application, you have access to the yAxis.scrollbar configuration, which provides more explicit control over Y-axis scrolling behavior. The Highcharts Stock API Reference documents this feature as “An optional scrollbar to display on the Y axis in response to limiting the minimum and maximum of the axis values.”
To disable Y-axis scrollbar when using Highstock, include the following in your yAxis configuration:
yAxis: {
scrollbar: {
enabled: false
}
}
This setting explicitly disables the scrollbar if it’s been enabled elsewhere in your configuration. According to the Highcharts documentation, “These scrollbars are enabled per axis and appear next to the axis. Scrollbars can be applied to any axis in Highcharts Stock.”
If you want to completely prevent any form of Y-axis scrolling or panning in Highstock, combine the scrollbar disabling with fixed min/max values:
yAxis: {
min: yourMinValue,
max: yourMaxValue,
scrollbar: {
enabled: false
},
// Additional settings to ensure no scrolling
startOnTick: false,
endOnTick: false
}
This comprehensive approach ensures that whether the scrollbar is visible or not, the Y-axis will remain locked within the specified range, preventing any unwanted vertical movement in your Highcharts Flutter implementation.
Advanced: afterSetExtremes Event for Control
For more sophisticated control over Y-axis behavior, you can use the afterSetExtremes event handler. This event fires whenever the axis extremes (min and max values) are changed, either by user interaction or programmatically. According to the Highcharts forum, “You just need to add a condition in afterSetExtremes event which will be checking if you are scrolling beyond the range of existing data.”
Implement this event handler in your yAxis configuration:
yAxis: {
events: {
afterSetExtremes: function(e) {
// Define your allowed range
const minAllowed = 0;
const maxAllowed = 100;
// If user has scrolled beyond allowed range, reset it
if (e.min < minAllowed || e.max > maxAllowed) {
this.setExtremes(minAllowed, maxAllowed, true, false);
}
}
}
}
This approach gives you fine-grained control over the axis range. The afterSetExtremes function checks if the new extremes exceed your predefined boundaries and resets them if necessary. The parameters in setExtremes are: min, max, redraw (optional), and animation (optional).
For Flutter implementations, you might want to add user feedback when the axis range is being reset. Consider showing a toast notification or visual indicator that the axis has reached its limit:
yAxis: {
events: {
afterSetExtremes: function(e) {
const minAllowed = 0;
const maxAllowed = 100;
if (e.min < minAllowed || e.max > maxAllowed) {
// In Flutter, you could trigger a callback to show a notification
if (window.HighchartsFlutter && window.HighchartsFlutter.onAxisLimitReached) {
window.HighchartsFlutter.onAxisLimitReached();
}
this.setExtremes(minAllowed, maxAllowed, true, false);
}
}
}
}
This advanced technique provides the most robust solution for preventing unwanted Y-axis scrolling while maintaining a smooth user experience.
Custom Mouse Wheel Handlers
If you’re still experiencing Y-axis scrolling despite implementing the previous solutions, the issue might be related to mouse wheel or touch gesture handling. As suggested in the Highcharts forum, “However, you can simply use scrollbar mousedown, mousemove, mouseup functions to handle mousewheel events on your scrollbar.”
To implement custom wheel handling that prevents Y-axis scrolling:
chart: {
events: {
load: function() {
// Store reference to chart
const chart = this;
// Add mouse wheel event listener
const container = chart.container;
// Prevent default wheel behavior on the chart container
container.addEventListener('wheel', function(e) {
// Only block vertical scrolling (deltaY)
if (Math.abs(e.deltaY) > Math.abs(e.deltaX)) {
e.preventDefault();
e.stopPropagation();
// Optionally, you could implement custom wheel behavior here
// For example, horizontal-only scrolling if needed
// chart.xAxis[0].setExtremes(
// chart.xAxis[0].min - e.deltaY * 0.1,
// chart.xAxis[0].max - e.deltaY * 0.1
// );
}
}, { passive: false });
}
}
}
This code attaches a wheel event listener to the chart container and prevents the default behavior for vertical scrolling (when deltaY is greater than deltaX). The { passive: false } option is crucial as it allows us to call preventDefault() on the event.
For Flutter implementations, you might need to coordinate between Flutter’s gesture handling and the WebView containing the Highcharts chart. Consider implementing custom gesture recognizers in Flutter that prevent vertical propagation when interacting with the chart area.
Another approach is to completely disable wheel interaction for the chart:
chart: {
events: {
load: function() {
const chart = this;
// Disable all wheel interaction
chart.container.addEventListener('wheel', function(e) {
e.preventDefault();
e.stopPropagation();
return false;
}, { passive: false });
}
}
}
This more aggressive approach prevents any wheel-based scrolling on the chart, which may be desirable in some Flutter applications where precise control over user interactions is required.
Flutter-Specific Implementation Tips
When implementing Highcharts in Flutter, there are several platform-specific considerations that can affect Y-axis scrolling behavior. The Flutter WebView wrapper that renders Highcharts might pass touch events differently than a browser environment, potentially causing unexpected vertical movement.
First, ensure your Flutter container properly constrains the chart’s rendering area. Use a Container with explicit dimensions and ClipRect to prevent overflow:
Container(
width: 300,
height: 200,
child: ClipRect(
child: WebView(
initialUrl: 'your_highcharts_page.html',
javascriptMode: JavascriptMode.unrestricted,
),
),
)
This approach ensures the chart cannot scroll vertically within its container, regardless of internal Highcharts configuration.
Second, consider implementing Flutter-side gesture handling to intercept and modify touch events before they reach the WebView. You can use a GestureDetector with custom behavior:
GestureDetector(
behavior: HitTestBehavior.translucent,
onVerticalDragDown: (details) {
// Prevent vertical drag from affecting the WebView
return;
},
child: WebView(
initialUrl: 'your_highcharts_page.html',
javascriptMode: JavascriptMode.unrestricted,
onWebViewCreated: (WebViewController controller) {
// Register JavaScript channel for communication
controller javascriptChannelJavascriptChannel(
JavascriptChannel(
name: 'HighchartsFlutter',
onMessageReceived: (JavascriptMessage message) {
// Handle messages from JavaScript
},
),
);
},
),
)
Third, coordinate between Flutter and JavaScript using the javascriptChannel feature. This allows your JavaScript code to signal when the axis limits are reached, as shown in the previous afterSetExtremes example:
// In your Highcharts configuration
yAxis: {
events: {
afterSetExtremes: function(e) {
if (e.min < 0 || e.max > 100) {
// Send message to Flutter
if (window.HighchartsFlutter && window.HighchartsFlutter.onAxisLimitReached) {
window.HighchartsFlutter.onAxisLimitReached.postMessage('Axis limit reached');
}
this.setExtremes(0, 100, true, false);
}
}
}
}
Finally, consider using a package like flutter_inappwebview which provides more advanced control over WebView behavior, including the ability to disable specific gestures:
InAppWebView(
initialUrlRequest: URLRequest(url: Uri.parse('your_highcharts_page.html')),
initialOptions: InAppWebViewGroupOptions(
crossPlatform: InAppWebViewOptions(
// Disables vertical scrolling in the WebView
disableVerticalScroll: true,
),
),
)
These Flutter-specific techniques, combined with the Highcharts configuration options, provide comprehensive control over Y-axis scrolling behavior in your Flutter applications.
Example Code and Configuration
Here’s a complete Highcharts configuration example that prevents Y-axis scrolling, suitable for use in Flutter applications:
const options = {
chart: {
type: 'line',
panning: {
enabled: false
},
zoomType: null,
events: {
load: function() {
const chart = this;
// Prevent wheel scrolling
chart.container.addEventListener('wheel', function(e) {
if (Math.abs(e.deltaY) > Math.abs(e.deltaX)) {
e.preventDefault();
e.stopPropagation();
return false;
}
}, { passive: false });
}
}
},
title: {
text: 'Fixed Y-axis Chart'
},
yAxis: {
min: 0,
max: 100,
startOnTick: false,
endOnTick: false,
scrollbar: {
enabled: false
},
events: {
afterSetExtremes: function(e) {
if (e.min < 0 || e.max > 100) {
// Optional: Notify Flutter
if (window.HighchartsFlutter && window.HighchartsFlutter.onAxisLimitReached) {
window.HighchartsFlutter.onAxisLimitReached();
}
this.setExtremes(0, 100, true, false);
}
}
}
},
xAxis: {
categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
},
series: [{
name: 'Data',
data: [65, 59, 80, 81, 56, 55, 40, 65, 78, 85, 90, 95]
}]
};
For the Flutter side, here’s a basic implementation using the webview_flutter package:
import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';
class HighchartsChart extends StatefulWidget {
@override
_HighchartsChartState createState() => _HighchartsChartState();
}
class _HighchartsChartState extends State<HighchartsChart> {
late WebViewController _controller;
@override
void initState() {
super.initState();
_controller = WebViewController()
..setJavaScriptMode(JavaScriptMode.unrestricted)
..setNavigationDelegate(
NavigationDelegate(
onProgress: (int progress) {
// Update loading indicator
},
onPageStarted: (String url) {
// Page loading started
},
onPageFinished: (String url) {
// Page loading finished
_controller.runJavaScript(
'''
// Initialize Highcharts with fixed Y-axis
const options = {
chart: {
type: 'line',
panning: { enabled: false },
zoomType: null,
events: {
load: function() {
const chart = this;
chart.container.addEventListener('wheel', function(e) {
if (Math.abs(e.deltaY) > Math.abs(e.deltaX)) {
e.preventDefault();
e.stopPropagation();
return false;
}
}, { passive: false });
}
}
},
title: { text: 'Fixed Y-axis Chart' },
yAxis: {
min: 0,
max: 100,
startOnTick: false,
endOnTick: false,
scrollbar: { enabled: false },
events: {
afterSetExtremes: function(e) {
if (e.min < 0 || e.max > 100) {
this.setExtremes(0, 100, true, false);
}
}
}
},
xAxis: { categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'] },
series: [{
name: 'Data',
data: [65, 59, 80, 81, 56, 55, 40, 65, 78, 85, 90, 95]
}]
};
Highcharts.chart('container', options);
'''
);
},
),
)
..loadRequest(Uri.parse('data:text/html,<html><body><div id="container" style="width:100%;height:400px;"></div><script src="https://code.highcharts.com/highcharts.js"></script></body></html>'));
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text('Highcharts Flutter')),
body: WebViewWidget(controller: _controller),
);
}
}
This example creates a complete Flutter application that loads a Highcharts chart with a fixed Y-axis that cannot be scrolled vertically. The configuration includes all the techniques discussed: disabling panning and zoom, setting fixed min/max values, disabling the scrollbar, implementing custom wheel handling, and using the afterSetExtremes event to enforce boundaries.
Troubleshooting and FAQs
Even after implementing the recommended solutions, you might encounter issues with Y-axis scrolling in your Highcharts Flutter implementation. Here are some common problems and their solutions:
Q: I’ve set min and max on the yAxis, but the chart still scrolls vertically. Why?
A: This can happen if the chart is configured to include complete data points with startOnTick: true and endOnTick: true. These settings adjust the axis range to include all data points, potentially overriding your min/max values. Set both to false to strictly enforce your specified range.
Q: My Highcharts chart is in a Flutter WebView, and touch events are causing unexpected behavior. How do I fix this?
A: Flutter’s WebView might pass touch events differently than a browser. Try wrapping your WebView in a GestureDetector with custom touch handling:
GestureDetector(
behavior: HitTestBehavior.translucent,
onVerticalDragDown: (details) => true, // Consume the event
child: WebView(...),
)
Q: The afterSetExtremes event isn’t firing. What’s wrong?
A: Ensure your yAxis has the events property correctly defined. Also verify that your chart actually has yAxis extremes being changed (either by user interaction or programmatically).
Q: I’m using Highstock and still see a Y scrollbar even with enabled: false.
A: Check if there’s another configuration enabling the scrollbar, such as in the global chart options or through a plugin. The Highstock API reference shows that yAxis.scrollbar should be explicitly set to enabled: false to disable it.
Q: My Flutter app crashes when trying to implement the custom wheel handler.
A: This might be due to timing issues. Ensure the chart is fully loaded before attaching event listeners. Use the chart’s load event to set up your handlers, as shown in the examples.
Q: How can I test if my Y-axis scrolling fix is working properly?
A: Implement boundary detection and user feedback. When the afterSetExtremes event fires and resets the range, show a notification or visual indicator in your Flutter app:
yAxis: {
events: {
afterSetExtremes: function(e) {
if (e.min < 0 || e.max > 100) {
// Send message to Flutter to show notification
if (window.HighchartsFlutter) {
window.HighchartsFlutter.postMessage('Axis limit reached');
}
this.setExtremes(0, 100, true, false);
}
}
}
}
In your Flutter code, set up a JavaScript channel to receive these messages:
_controller = WebViewController()
..setJavaScriptMode(JavaScriptMode.unrestricted)
..addJavaScriptChannel(
'HighchartsFlutter',
onMessageReceived: (JavaScriptMessage message) {
ScaffoldMessenger.of(context).showSnackBar(
SnackBar(content: Text(message.message)),
);
},
);
Q: I want to allow horizontal scrolling but prevent vertical scrolling. How can I achieve this?
A: Modify your wheel event handler to only prevent vertical scrolling:
chart.container.addEventListener('wheel', function(e) {
if (Math.abs(e.deltaY) > Math.abs(e.deltaX)) {
e.preventDefault();
e.stopPropagation();
// Optionally, implement horizontal scrolling instead
chart.xAxis[0].setExtremes(
chart.xAxis[0].min - e.deltaY * 0.1,
chart.xAxis[0].max - e.deltaY * 0.1
);
}
}, { passive: false });
This approach allows users to scroll horizontally while preventing unwanted vertical movement.
By addressing these common issues and implementing the recommended solutions, you can effectively disable Y-axis scrolling in your Highcharts Flutter applications, providing a stable and predictable user experience.
Sources
- Highcharts Official Documentation - Scrollbars
- Highcharts Stock API Reference - yAxis.scrollbar
- Highcharts Blog - Scrollbars for any axis
- Highcharts Official Forum - Fixed Y-Axis on scrollable chart
- Highcharts Official Forum - Scroll y-Axis with wheel
- Highcharts Official Forum - Scroll with mouse wheel
- Highcharts GitHub - Multiple Y-Axis with scrollbars issue
Conclusion
Disabling Y-axis scrolling in Highcharts Flutter requires a multi-faceted approach that combines configuration options, event handling, and Flutter-specific implementation techniques. The most effective solution involves setting explicit min and max values on the yAxis, which creates a fixed range that users cannot scroll beyond. For Highstock implementations, explicitly disabling the yAxis.scrollbar provides additional control.
When basic configuration isn’t sufficient, implementing custom wheel event handlers and using the afterSetExtremes event offer more sophisticated control over axis behavior. These techniques allow you to detect and prevent unwanted vertical movement while maintaining a smooth user experience.
Flutter-specific considerations are equally important, as the WebView wrapper might pass touch events differently than a browser environment. Properly constraining the chart container and implementing custom gesture handling at the Flutter level can prevent vertical scrolling before it even reaches the Highcharts implementation.
By combining these approaches—configuration fixes, advanced event handling, and Flutter-specific techniques—you can create a stable, predictable Highcharts Flutter chart that maintains full functionality while eliminating unwanted Y-axis scrolling. The key is to layer multiple solutions as needed, ensuring robust protection against vertical movement in all usage scenarios.