allow user to select media image subsection using the mouse

svn: r11140

src/Editors/_EditMediaRef.py

@@ -117,9 +117,17 @@ class EditMediaRef(EditReference):
             self.top.get_widget("type").set_text("")
 
     def _setup_fields(self):
-        ebox = self.top.get_widget('eventbox')
-        ebox.connect('button-press-event', self.button_press_event)
-        
+        ebox_shared = self.top.get_widget('eventbox')
+        ebox_shared.connect('button-press-event', self.button_press_event)
+
+        if not self.dbstate.db.readonly:
+            self.button_press_coords = (0, 0)
+            ebox_ref = self.top.get_widget('eventbox1')
+            ebox_ref.connect('button-press-event', self.button_press_event_ref)
+            ebox_ref.connect('button-release-event', self.button_release_event_ref)
+            ebox_ref.add_events(gtk.gdk.BUTTON_PRESS_MASK)
+            ebox_ref.add_events(gtk.gdk.BUTTON_RELEASE_MASK)
+
         self.pixmap = self.top.get_widget("pixmap")
         
         coord = self.source_ref.get_rectangle()
@@ -381,6 +389,94 @@ class EditMediaRef(EditReference):
         if event.button==1 and event.type == gtk.gdk._2BUTTON_PRESS:
             self.view_media(obj)
 
+    def button_press_event_ref(self, widget, event):
+        """
+        Handle the button-press-event generated by the eventbox
+        parent of the subpixmap.  Remember these coordinates
+        so we can crop the picture when button-release-event
+        is received.
+        """
+        self.button_press_coords = (event.x, event.y)
+
+    def button_release_event_ref(self, widget, event):
+        """
+        Handle the button-release-event generated by the eventbox
+        parent of the subpixmap.  Crop the picture accordingly.
+        """
+
+        # reset the crop on double-click or click+CTRL
+        if (event.button==1 and event.type == gtk.gdk._2BUTTON_PRESS) or \
+            (event.button==1 and (event.state & gtk.gdk.CONTROL_MASK) ):
+            self.corner1_x_spinbutton.set_value(0)
+            self.corner1_y_spinbutton.set_value(0)
+            self.corner2_x_spinbutton.set_value(100)
+            self.corner2_y_spinbutton.set_value(100)
+
+        else:
+
+            # ensure the clicks happened at least 5 pixels away from each other
+            new_x1 = min(self.button_press_coords[0], event.x)
+            new_y1 = min(self.button_press_coords[1], event.y)
+            new_x2 = max(self.button_press_coords[0], event.x)
+            new_y2 = max(self.button_press_coords[1], event.y)
+
+            if new_x2 - new_x1 >= 5 and new_y2 - new_y1 >= 5:
+
+                # get the image size and calculate the X and Y offsets
+                # (image is centered when smaller than const.THUMBSCALE)
+                pixbuf = self.subpixmap.get_pixbuf();
+                w = pixbuf.get_width()
+                h = pixbuf.get_height()
+                x = (const.THUMBSCALE - w) / 2
+                y = (const.THUMBSCALE - h) / 2
+
+                # if the click was outside of the image,
+                # bring it within the boundaries
+                if new_x1 < x:
+                    new_x1 = x
+                if new_y1 < y:
+                    new_y1 = y
+                if new_x2 >= x + w:
+                    new_x2 = x + w - 1
+                if new_y2 >= y + h:
+                    new_y2 = y + h - 1
+
+                # get the old spinbutton % values
+                old_x1 = self.corner1_x_spinbutton.get_value()
+                old_y1 = self.corner1_y_spinbutton.get_value()
+                old_x2 = self.corner2_x_spinbutton.get_value()
+                old_y2 = self.corner2_y_spinbutton.get_value()
+                delta_x = old_x2 - old_x1   # horizontal scale
+                delta_y = old_y2 - old_y1   # vertical scale
+
+                # Took a while to figure out the math here.
+                #
+                #   1)  figure out the current crop % values
+                #       by doing the following:
+                #
+                #           xp = click_location_x / width * 100
+                #           yp = click_location_y / height * 100
+                #
+                #       but remember that click_location_x and _y
+                #       might not be zero-based for non-rectangular
+                #       images, so subtract the pixbuf "x" and "y"
+                #       to bring the values back to zero-based
+                #
+                #   2)  the minimum value cannot be less than the
+                #       existing crop value, so add the current
+                #       minimum to the new values
+
+                new_x1 = old_x1 + delta_x * (new_x1 - x) / w
+                new_y1 = old_y1 + delta_y * (new_y1 - y) / h
+                new_x2 = old_x1 + delta_x * (new_x2 - x) / w
+                new_y2 = old_y1 + delta_y * (new_y2 - y) / h
+
+                # set the new values
+                self.corner1_x_spinbutton.set_value(new_x1)
+                self.corner1_y_spinbutton.set_value(new_y1)
+                self.corner2_x_spinbutton.set_value(new_x2)
+                self.corner2_y_spinbutton.set_value(new_y2)
+
     def _update_addmedia(self, obj):
         """
         Called when the add media dialog has been called.