Stop speaker positions jumping around when clicked on.

[ardour.git] / gtk2_ardour / speaker_dialog.cc

diff --git a/gtk2_ardour/speaker_dialog.cc b/gtk2_ardour/speaker_dialog.cc
index 7c87047a7f986d56ccf14034a4ac432a1c08c4fc..3b2418ec0c7dce1a8d302274d1e3ec3dce1f70bb 100644 (file)
--- a/gtk2_ardour/speaker_dialog.cc
+++ b/gtk2_ardour/speaker_dialog.cc
@@ -99,9 +99,7 @@ SpeakerDialog::darea_expose_event (GdkEventExpose* event)
        cairo_fill_preserve (cr);
        cairo_clip (cr);
 
-       if (height > 100) {
-               cairo_translate (cr, 10.0, 10.0);
-       }
+       cairo_translate (cr, x_origin, y_origin);
 
        /* horizontal line of "crosshairs" */
 
@@ -218,6 +216,9 @@ SpeakerDialog::darea_size_allocate (Gtk::Allocation& alloc)
                width -= 20;
                height -= 20;
        }
+
+       x_origin = (alloc.get_width() - width) / 2;
+       y_origin = (alloc.get_height() - height) / 2;
 }
 
 bool
@@ -234,13 +235,23 @@ SpeakerDialog::darea_button_press_event (GdkEventButton *ev)
        switch (ev->button) {
        case 1:
        case 2:
+       {
                drag_index = find_closest_object (ev->x, ev->y);
-               drag_x = (int) floor (ev->x);
-               drag_y = (int) floor (ev->y);
+               int const drag_x = (int) floor (ev->x);
+               int const drag_y = (int) floor (ev->y);
                state = (GdkModifierType) ev->state;
 
+               if (drag_index >= 0) {
+                       CartesianVector c;
+                       speakers.speakers()[drag_index].angles().cartesian (c);
+                       cart_to_gtk (c);
+                       drag_offset_x = drag_x - x_origin - c.x;
+                       drag_offset_y = drag_y - y_origin - c.y;
+               }
+
                return handle_motion (drag_x, drag_y, state);
                break;
+       }
 
        default:
                break;
@@ -356,6 +367,17 @@ SpeakerDialog::handle_motion (gint evx, gint evy, GdkModifierType state)
                return false;
        }
 
+       /* correct event coordinates to have their origin at the corner of our graphic
+          rather than the corner of our allocation */
+
+       double obx = evx - x_origin;
+       double oby = evy - y_origin;
+
+       /* and compensate for any distance between the mouse pointer and the centre
+          of the object being dragged */
+
+       obx -= drag_offset_x;
+       oby -= drag_offset_y;
 
        if (state & GDK_BUTTON1_MASK && !(state & GDK_BUTTON2_MASK)) {
                CartesianVector c;
@@ -365,12 +387,12 @@ SpeakerDialog::handle_motion (gint evx, gint evy, GdkModifierType state)
                moving.angles().cartesian (c);
                cart_to_gtk (c);
 
-               if ((evx != c.x) || (evy != c.y)) {
+               if (obx != c.x || oby != c.y) {
                        need_move = true;
                }
 
                if (need_move) {
-                       CartesianVector cp (evx, evy, 0.0);
+                       CartesianVector cp (obx, oby, 0.0);
 
                        /* canonicalize position */