new class for widgets adjustable by rotation-like gestures

(bzr r3949)

1 files changed, 137 insertions, 0 deletions

diff --git a/src/ui/widget/rotateable.cpp b/src/ui/widget/rotateable.cpp
new file mode 100644
index 000000000..e434c10c5
--- /dev/null
+++ b/src/ui/widget/rotateable.cpp
@@ -0,0 +1,137 @@
+/**
+ * \brief widget adjustable by dragging it to rotate away from a zero-change axis
+ *
+ * Authors:
+ *   buliabyak@gmail.com
+ *
+ * Copyright (C) 2007 authors
+ *
+ * Released under GNU GPL.  Read the file 'COPYING' for more information.
+ */
+
+#include "event-context.h"
+#include "rotateable.h"
+#include "libnr/nr-point.h"
+#include "libnr/nr-point-fns.h"
+#include <gtkmm/box.h>
+#include <gtkmm/eventbox.h>
+#include <glibmm/i18n.h>
+
+namespace Inkscape {
+namespace UI {
+namespace Widget {
+
+	Rotateable::Rotateable():
+    axis(-M_PI/4),
+    maxdecl(M_PI/4)
+  {
+		dragging = false;
+		working = false;
+		modifier = 0;
+		current_axis = axis;
+
+    signal_button_press_event().connect(sigc::mem_fun(*this, &Rotateable::on_click));
+    signal_motion_notify_event().connect(sigc::mem_fun(*this, &Rotateable::on_motion));
+    signal_button_release_event().connect(sigc::mem_fun(*this, &Rotateable::on_release));
+	}
+
+  bool Rotateable::on_click(GdkEventButton *event) {
+		if (event->button == 1) {
+			drag_started_x = event->x;
+			drag_started_y = event->y;
+			modifier = get_single_modifier(modifier, event->state); 
+  		dragging = true;
+  		working = false;
+			current_axis = axis;
+  	  return true;
+		} 
+		return false; 
+	}
+
+  guint Rotateable::get_single_modifier(guint old, guint state) {
+
+		if (old == 0) {
+			if (state & GDK_CONTROL_MASK)
+				return 1; // ctrl
+			if (state & GDK_SHIFT_MASK)
+				return 2; // shift
+			return 0;
+		} else {
+			if (!(state & GDK_CONTROL_MASK) && !(state & GDK_SHIFT_MASK))
+				return 0; // none
+			if (old == 1) 
+  			if (state & GDK_SHIFT_MASK && !(state & GDK_CONTROL_MASK))
+	  			return 2; // shift
+        else 
+          return 1;
+			if (old == 2) 
+  			if (state & GDK_CONTROL_MASK && !(state & GDK_SHIFT_MASK))
+	  			return 1; // ctrl
+        else 
+          return 2;
+  		return old;
+		}
+	}
+
+
+  bool Rotateable::on_motion(GdkEventMotion *event) {
+		if (dragging) {
+			double dist = NR::L2(NR::Point(event->x, event->y) - NR::Point(drag_started_x, drag_started_y));
+			double angle = atan2(event->y - drag_started_y, event->x - drag_started_x);
+			if (dist > 20) {
+				working = true;
+  			double force = CLAMP (-(angle - current_axis)/maxdecl, -1, 1);
+	  		if (fabs(force) < 0.002)
+		  		force = 0; // snap to zero
+				if (modifier != get_single_modifier(modifier, event->state)) { 
+          // user has switched modifiers in mid drag, close past drag and start a new
+          // one, redefining axis temporarily
+	  			do_release(force, modifier);
+					current_axis = angle;
+    			modifier = get_single_modifier(modifier, event->state); 
+				} else {
+	  			do_motion(force, modifier);
+				}
+			}
+      gobble_motion_events(GDK_BUTTON1_MASK);
+  		return true;
+		} 
+		return false; 
+	}
+
+
+  bool Rotateable::on_release(GdkEventButton *event) {
+		if (dragging && working) {
+			double angle = atan2(event->y - drag_started_y, event->x - drag_started_x);
+			double force = CLAMP (-(angle - current_axis)/maxdecl, -1, 1);
+			if (fabs(force) < 0.002)
+				force = 0; // snap to zero
+			do_release(force, modifier);
+			dragging = false;
+			working = false;
+			current_axis = axis;
+			return true;
+		}
+		return false;
+	}
+
+
+	Rotateable::~Rotateable() {
+	}
+
+
+
+} // namespace Widget
+} // namespace UI
+} // namespace Inkscape
+
+/* 
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=c++:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :