QChartViewer.setZoomDirection

void setZoomDirection(int direction);

Sets the zoom direction for mouse zoom in/out actions.

In zoom operations for charts, it is common to restrict zooming to one direction only. For example, in a chart plotting temperature against time, zooming in from a yearly chart to a daily chart may mean the time axis (x-axis) is zoomed in by 36500%, while the temperature axis (y-axis) may be auto-scaled and not zoomed in at all. The user may be surprise if you also zoom in the y-axis by 36500%, in which case the chart may become hardly readable.

This method allows you to determine the zoom direction for mouse zoom actions (see QChartViewer.setMouseUsage), specified using the following predefined constants:

Constant	Value	Description
DirectionHorizontal	0	Zoom actions apply to horizontal direction only.
DirectionVertical	1	Zoom actions apply to vertical direction only.
DirectionHorizontalVertical	2	Zoom actions apply to both horizontal and vertical directions.
KeepAspectRatio	3	Zoom actions apply to both horizontal and vertical directions and with the same ratio.

Argument	Default	Description
direction	(Mandatory)	The zoom direction for mouse zoom actions.

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