- Describing the Chart control: Options specific to multi-touch
- Optional events specific to multi-touch
Multi-touch in a Chart control
One of the most common applications of the multi-touch feature is used to handle images. Since mobile devices usually have smaller screens, sometimes it is necessary to zoom and move images.
Charts are a special type of image.
This allows you to perform a zoom on a Chart via the contact of 2 fingers moving apart.
Multi-touch in a Chart control allows the user:
- to increase of decrease the chart's size using two fingers.
- to display a specific tooltip when touching a chart value with a finger. This tooltip contains the corresponding value by default.
- to execute a specific event when touching a chart value.
WINDEV Mobile allows you to manage the multi-touch in the Chart controls found in the applications via:
Describing the Chart control: Options specific to multi-touch
The "Details" tab in the window description of the Chart control is used to manage the actions performed when using the fingers.
The zoom can be managed by the following options:
- Allow horizontal zoom.
- Allow vertical zoom.
In this case:
- spreading out two fingers in contact with the screen is used to zoom inside the chart. The zoom will be centered on the point found in the middle of the line drawn by the two contact points.
- pinching two fingers together that are in contact with the screen allows you to zoom out in the chart.
Remark: The multi-touch features of the Image control cannot be used if the window includes a scrollbar.
Optional events specific to multi-touch
By default, when the user presses a finger onto a value in the chart, a tooltip comes up. This tooltip contains the current value and it can be customized via grTooltip
A specific event is associated with the Chart control: "Before the tooltip display". This event is used, for example, to run a specific event when the user touches a chart value.