draw hover snap point

SketchWidget.py

@@ -24,7 +24,7 @@ class SketchWidget:
                 'arrow': gtk.gdk.Cursor(gtk.gdk.ARROW),
                 'crosshair': gtk.gdk.Cursor(gtk.gdk.CROSSHAIR),
                 }
-        self.current_snap_point = None
+        self.hover_snap_point = None
 
         # Configuration parameters
         self.line_width = 1.5
@@ -34,6 +34,7 @@ class SketchWidget:
         self.background_color = (0.0, 0.05, 0.1, 1.0)
         self.line_color = (0.1, 0.6, 1.0, 1.0)
         self.axis_color = (1.0, 0.0, 0.0, 1.0)
+        self.hover_color = (1.0, 1.0, 1.0, 1.0)
         self.constraint_color = (0.8, 1.0, 0.0, 1.0)
         self.snap_angle = 10
         self.hv_snap_dist = 10
@@ -132,6 +133,11 @@ class SketchWidget:
             for c in self.drawingConstraints:
                 self.drawConstraint(c)
 
+        if self.hover_snap_point is not None:
+            glColor(*self.hover_color)
+            s, p = self.hover_snap_point
+            self.drawConnect(Connect(s, p, s, p))
+
         if gldrawable.is_double_buffered():
             gldrawable.swap_buffers()
         else:
@@ -408,6 +414,8 @@ class SketchWidget:
                 self.drawingConstraints = []
             self.drawingShape.setPt(1, this_pt)
             self.queue_redraw()
+        sp = self.get_closest_snap_point(x, y)
+        self.update_hover_snap_point(sp)
 
     def do_circle_left_click(self, x, y):
         pt = self.screenPtToPt((x, self.size[1] - y))
@@ -428,10 +436,14 @@ class SketchWidget:
             r = self.dist_bw(self.drawingShape.getPt(0), pt)
             self.drawingShape.setRadius(r)
             self.queue_redraw()
+        else:
+            sp = self.get_closest_snap_point(x, y)
+            self.update_hover_snap_point(sp)
 
     def cancel_drawing_shape(self):
         self.drawingShape = None
         self.drawingConstraints = []
+        self.hover_snap_point = None
 
     def merge_in_drawing_shape(self):
         self.sketch.shapes.append(self.drawingShape)
@@ -445,6 +457,11 @@ class SketchWidget:
         y = pt2[1] - pt1[1]
         return math.sqrt(x * x + y * y)
 
+    def dist2_bw(self, pt1, pt2):
+        x = pt2[0] - pt1[0]
+        y = pt2[1] - pt1[1]
+        return x * x + y * y
+
     def update_snap_points(self):
         self.snap_points = {}
         for s in self.sketch.shapes:
@@ -454,3 +471,27 @@ class SketchWidget:
         for i in range(shape.nPts()):
             pt = self.ptToScreenPt(shape.getPt(i))
             self.snap_points[(shape, i)] = pt
+
+    def get_closest_snap_point(self, x, y):
+        closest_point = None
+        closest_dist = self.snap_dist * self.snap_dist * 2
+        for p in self.snap_points:
+            shape, ptNum = p
+            pt = self.ptToScreenPt(shape.getPt(ptNum))
+            dist = self.dist2_bw((x, self.size[1] - y), pt)
+            if dist < closest_dist:
+                closest_dist = dist
+                closest_point = p
+        if closest_dist <= self.snap_dist * self.snap_dist:
+            return closest_point
+        return None
+
+    def update_hover_snap_point(self, sp):
+        if sp is not None:
+            if sp != self.hover_snap_point:
+                self.hover_snap_point = sp
+                self.queue_redraw()
+        else:
+            if self.hover_snap_point is not None:
+                self.hover_snap_point = None
+                self.queue_redraw()