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Greetings all,
I am new to GTK. So far, lots of fun. I am
developing a small application to view large images. One feature includes using
a mouse button to pan the image within the viewing window. I
have one problem.
1) On the release of the mouse button, I would like
to interrupt the event queue, execute only the button release handler, and
cancel all other remaining events. It is preferable if an event
was being handled when the button was released, that the event be
allowed to complete successfully.
The basic logic follows:
/* start snippet */
gint top,left,old_x,old_y,x,y;
guchar *imageArray;
redrawImage() {
gtk_draw_rgb_image(...,top,left,...,imageArray,...);
}
moveImage(x,y) {
left =
adjust_left_by_x();
top =
adjust_top_by_y();
redrawImage();
}
delete_event();
expose_event() {
redrawImage();
}
button_press_event() {
old_x = x =
event->x;
old_y = y =
event->y;
}
motion_notify_event() {
moveImage((event->x -
old_x),(event->y - old_y);
old_x = x;
old_y = y;
button_release_event() {
/*
* How do I interrupt the
event queue and process only this callback,
* as soon as the button
is released?
*/
moveImage((event->x -
old_x),(event->y - old_y);
}
main() {
/* gtk init stuff, create a
new window */
drawArea =
gtk_drawing_area_new();
gtk_signal_connect(GTK_OBJECT(drawArea), "expose_event",
GTK_SIGNAL_FUNC(expose_event), NULL);
gtk_signal_connect(GTK_OBJECT(drawArea), "button_press_event",
GTK_SIGNAL_FUNC(button_press_event), NULL);
gtk_signal_connect(GTK_OBJECT(drawArea), "button_release_event",
GTK_SIGNAL_FUNC(button_release_event), NULL);
gtk_signal_connect(GTK_OBJECT(drawArea), "motion_notify_event",
GTK_SIGNAL_FUNC(motion_notify_event), NULL);
gtk_widget_set_events(drawArea,GDK_EXPOSURE_MASK
|GDK_BUTTON_PRESS_MASK |GDK_BUTTON_RELEASE_MASK |GDK_POINTER_MOTION_MASK); /* pack the drawArea
into the window, show all, & run gtk_main(); */
}
/* end snippet */
Thanks,
Kevin Mullican
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