iOS & macOS Charting Documentation - SciChart iOS & macOS Charts SDK v4.x

The SCIPinchZoomModifier

SciChart iOS provides pinch zooming via the SCIPinchZoomModifier, available out of the box.

Besides common features which are inherited from the SCIChartModifierBase class, the SCIPinchZoomModifier allows to control its specific features via the following properties:

SCIPinchZoomModifier.scaleFactor - allows to set ScaleFactor to change zooming speed.
SCIPinchZoomModifier.direction - allows to restrict zooming to the horizontal or vertical direction only if needed.

Adding a SCIPinchZoomModifier to a Chart

Any Chart Modifier can be added to a SCIChartSurface via the ISCIChartSurface.chartModifiers property and SCIPinchZoomModifier with no difference:

    // Assume a surface has been created and configured somewhere
    id<ISCIChartSurface> surface;

    // Create a Modifier
    SCIPinchZoomModifier *pinchZoomModifier = [SCIPinchZoomModifier new];
    pinchZoomModifier.direction = SCIDirection2D_XDirection;
    pinchZoomModifier.scaleFactor = 1.5;

    // Add the modifier to the surface
    [self.surface.chartModifiers add:pinchZoomModifier];

    // Assume a surface has been created and configured somewhere
    let surface: ISCIChartSurface

    // Create a Modifier
    let pinchZoomModifier = SCIPinchZoomModifier()
    pinchZoomModifier.direction = .xDirection
    pinchZoomModifier.scaleFactor = 1.5

    // Add the modifier to the surface
    self.surface.chartModifiers.add(pinchZoomModifier)

    // Assume a surface has been created and configured somewhere
    IISCIChartSurface surface;

    // Create a Modifier
    var pinchZoomModifier = new SCIPinchZoomModifier();
    pinchZoomModifier.Direction = SCIDirection2D.XDirection;
    pinchZoomModifier.scaleFactor = 1.5;

    // Add the modifier to the surface
    Surface.ChartModifiers.Add(pinchZoomModifier);

Additional Properties

Restricting Interaction to a Single Direction (X or Y)

Interaction for this modifier can be limited to a specific axis direction by configuring the direction property. This feature is especially useful in multiple-axis charts, where you may want to zoom only selected axes while keeping others fixed. Set direction to one of the SCIDirection2D values to restrict the modifier to the X-axis, Y-axis, or both.

pinchZoomModifier.direction = SCIDirection2D_XyDirection; // Allows interaction in both directions
pinchZoomModifier.direction = SCIDirection2D_XDirection;  // X-axis only
pinchZoomModifier.direction = SCIDirection2D_YDirection;  // Y-axis only

pinchZoomModifier.direction = .xyDirection    // Allows interaction in both directions
pinchZoomModifier.direction = .xDirection     // X-axis only
pinchZoomModifier.direction = .yDirection     // Y-axis only

Include/Exclude Certain Axis from Pinch Zoom

The SCIPinchZoomModifier allows you to include or exclude certain axis from the pinch zoom operation. By default all axis are included, to exclude one or more X or Y axis, set the following property:

// Exclude a specific axis from the pan zoom operation
[pinchZoomModifier includeXAxis:xAxis isIncluded:NO];
[pinchZoomModifier includeYAxis:yAxis isIncluded:NO];

// Include a specific axis from the pan zoom operation
[pinchZoomModifier includeXAxis:xAxis isIncluded:YES];
[pinchZoomModifier includeYAxis:yAxis isIncluded:YES];

// Reset flags
[pinchZoomModifier includeAll];
[pinchZoomModifier excludeAll];

// Exclude a specific axis from the pan zoom operation
pinchZoomModifier.includeXAxis(xAxis, isIncluded: false)
pinchZoomModifier.includeYAxis(yAxis, isIncluded: false)

// Include a specific axis from the pan zoom operation
pinchZoomModifier.includeXAxis(xAxis, isIncluded: true)
pinchZoomModifier.includeYAxis(yAxis, isIncluded: true)

// Reset flags
pinchZoomModifier.includeAll()
pinchZoomModifier.excludeAll()

NOTE: To learn more about features available, please visit the Chart Modifier APIs article.

FAQ

Q: How to keyboard zoom on +/- keys in macOS?
A: To implement zooming via keyboard on macOS using the + and - keys, override the keyDown(with:) method in your chart-hosting view or responder, detect the appropriate key input, compute a zoom scale, and update the visibleRange of your SCINumericAxis accordingly. For more details, see the documentation: Zoom and Pan – Mouse Wheel and Trackpad Support

Q: Whether chart content supports mouse-wheel zooming A: We don’t have a built in scroll modifier for macOS, but it would done by overriding scrollWheel(with event: NSEvent) method. For more details, see the documentation: Zoom and Pan – Mouse Wheel and Trackpad Support