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Description
GtkGestureZoom is a GtkGesture implementation able to recognize pinch/zoom gestures, whenever the distance between both tracked sequences changes, the “scale-changed” signal is emitted to report the scale factor.
Functions
gtk_gesture_zoom_new ()
GtkGesture *
gtk_gesture_zoom_new (GtkWidget *widget);
Returns a newly created GtkGesture that recognizes zoom in/out gestures (usually known as pinch/zoom).
Since 3.14
gtk_gesture_zoom_get_scale_delta ()
gdouble
gtk_gesture_zoom_get_scale_delta (GtkGestureZoom *gesture);
If gesture
is active, this function returns the zooming difference
since the gesture was recognized (hence the starting point is
considered 1:1). If gesture
is not active, 1 is returned.
Since 3.14
Signal Details
The “scale-changed” signal
void user_function (GtkGestureZoom *controller, gdouble scale, gpointer user_data)
This signal is emitted whenever the distance between both tracked sequences changes.
Parameters
controller |
the object on which the signal is emitted |
|
scale |
Scale delta, taking the initial state as 1:1 |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run First
Since 3.14