Colin Thomas a écrit :
>
> Hi,
>
> I would like to be able to click on a Drawing area and extract
> the cursors position, and possibly drag-select over its suface.
>
> Are there any tutorials on this?
>
> I have connected a function to the button release on the Drawing
> Area (see below), this does not seem to trigger the function call,
>
> gtk_signal_connect (GTK_OBJECT (guiDrawingArea), "button_press_event",
> GTK_SIGNAL_FUNC (on_guiDrawingArea_button_press_event),
> NULL);
>
> But even if I managed to get the function call to execute, from where do
> I extract the cursor's location..
>
> I look forward to your collective wisdom..
>
> Many thanks in advance..
>
> Colin Thomas.
>
Hi,
I never use a Drawing area but there is some rules that can be apply.
First if the widget don't catch the event you want, then you have to set
it :
gtk_widget_set_events(GTK_WIDGET(glarea),
GDK_BUTTON_PRESS_MASK|
GDK_BUTTON_RELEASE_MASK);
if you want to catch only button_press, and button_release...
Then connect your function as you have done.
In this function you have a prototype. For example button_press have
this
prototype (You can find this in the GtkWidget doc) :
gboolean user_function (GtkWidget *widget,
GdkEventButton *event,
gpointer user_data);
which mean that your function must be like this :
gboolean on_guiDrawingArea_button_press_event (GtkWidget *widget,
GdkEventButton *event,
gpointer user_data);
In the field event, you have a GdkEventButton. This GdkEventButton has
this structure
GdkEventType type;
GdkWindow *window;
gint8 send_event;
guint32 time;
gdouble x;
gdouble y;
gdouble pressure;
gdouble xtilt;
gdouble ytilt;
guint state;
guint button;
GdkInputSource source;
guint32 deviceid;
gdouble x_root, y_root;
where x and y is where you have pressed
Should look to the GdkEvent doc.
Hope this help
--
Florent DEVIN
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