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- Overview
- Image field description: Multi-touch-specific options
- Optional events specific to multi-touch
- Scroll with finger optional event
- Horizontal and vertical swipe
- "Zoom with fingers" optional process
Multi-touch in an Image 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. This technology allows you to zoom images with a pinch gesture. The multi-touch can be implemented: - on the applications run on a phone.
- on the sites displayed on a phone.
The management of multi-touch in the Image controls can be implemented via: Image field description: Multi-touch-specific options The "Details" tab in the window description of the Image control is used to manage the actions performed when using the fingers: You can manage: - No scroll, no zoom: in this case, multi-touch is disabled.
- Automatic scroll only: If the image is not displayed in its entirety in the field, it can be moved by scrolling directly in the image with the finger.
- Automatic scroll and zoom: In addition to scrolling, it is possible to zoom in and out.. In this case:
- moving two fingers away from each other on the screen allows zooming in. The zoom will be centered on the point found in the middle of the line drawn by the two contact points.
- moving two fingers towards each other on the screen allows zooming out.
The additional options are used to define: - Maximum zoom factor: Maximum zoom with fingertips.
- Enable double-tap scaling: In this case, a double-tap (or double-click) in the field enables zooming in on an image area.. If the image is already zoomed, it is reinitialized to its initial display.
Optional events specific to multi-touch There are three specific optional events to manage multi-touch on Image controls: Scroll with finger optional event The "Scroll with finger" event is run when one or more fingers move vertically or horizontally while in contact with the screen This event can accept parameters by declaring a procedure directly in the "Scroll with finger" event with the following syntax: PROCEDURE <Procedure name>(<Distance X>, <Distance Y>) where: - <Distance X> Integer corresponding to the distance (in pixels) scrolled along the X axis in the field.
- <Distance Y> Integer corresponding to the distance (in pixels) scrolled along the Y axis in the field.
Remarks:  The distance corresponds to the distance between the first contact point that was detected and the current position.
Horizontal and vertical swipe The "Horizontal and vertical swipe" event is run during a quick small movement of one or more fingers on the screen. This event can accept parameters by declaring a procedure directly in the "Horizontal and vertical swipe" event with the following syntax: PROCEDURE <Procedure name>(<Speed X>, <Speed Y>) where: - <Vitesse X> Integer corresponding to the speed (in pixels per second) of movement on the X axis.
- <Vitesse Y> Integer corresponding to the speed (in pixels per second) of movement on the Y axis.
"Zoom with fingers" optional process The "Zoom with fingers" event is run with a pinch or spread finger gesture on the screen. This event can accept parameters by declaring a procedure directly in the "Zoom with fingers" event with the following syntax: PROCEDURE <Procedure name>(<Spacing>) where <Ecartement>: Integer corresponding to the distance (in pixels) between the two contact points when the event is called. Caution: Pinch zoom is not available if the dStartDrawing function is used in the Image field.. In this case, you must: - save the image with a dSaveImageXXX function.
- use the dEndDrawing function.
- redisplay the image in the Image control.
Related Examples:
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Cross-platform examples (WINDEV Mobile): WM System
[ + ] This application is an example of some of the features of WINDEV Mobile available for Android/iOS. The following system functions are used: - NFC - Multimedia control - Brightness - Volume - Wi-Fi - Bluetooth - Toast - Compass - Accelerometer - Camera control - LED - Vibration - Notifications - Drawing functions - Internet
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