Interactively adding point to edge

labelme/app.py

@@ -399,14 +399,6 @@ class MainWindow(QtWidgets.QMainWindow):
             self.tr("Undo last drawn point"),
             enabled=False,
         )
-        addPointToEdge = action(
-            text=self.tr("Add Point to Edge"),
-            slot=self.canvas.addPointToEdge,
-            shortcut=shortcuts["add_point_to_edge"],
-            icon="edit",
-            tip=self.tr("Add point to the nearest edge"),
-            enabled=False,
-        )
         removePoint = action(
             text="Remove Selected Point",
             slot=self.removeSelectedPoint,
@@ -573,7 +565,6 @@ class MainWindow(QtWidgets.QMainWindow):
             copy=copy,
             undoLastPoint=undoLastPoint,
             undo=undo,
-            addPointToEdge=addPointToEdge,
             removePoint=removePoint,
             createMode=createMode,
             editMode=editMode,
@@ -603,8 +594,6 @@ class MainWindow(QtWidgets.QMainWindow):
                 undo,
                 undoLastPoint,
                 None,
-                addPointToEdge,
-                None,
                 toggle_keep_prev_mode,
             ),
             # menu shown at right click
@@ -621,7 +610,6 @@ class MainWindow(QtWidgets.QMainWindow):
                 delete,
                 undo,
                 undoLastPoint,
-                addPointToEdge,
                 removePoint,
             ),
             onLoadActive=(
@@ -638,7 +626,6 @@ class MainWindow(QtWidgets.QMainWindow):
             onShapesPresent=(saveAs, hideAll, showAll),
         )
 
-        self.canvas.edgeSelected.connect(self.canvasShapeEdgeSelected)
         self.canvas.vertexSelected.connect(self.actions.removePoint.setEnabled)
 
         self.menus = utils.struct(
@@ -877,11 +864,6 @@ class MainWindow(QtWidgets.QMainWindow):
         for action in self.actions.onLoadActive:
             action.setEnabled(value)
 
-    def canvasShapeEdgeSelected(self, selected, shape):
-        self.actions.addPointToEdge.setEnabled(
-            selected and shape and shape.canAddPoint()
-        )
-
     def queueEvent(self, function):
         QtCore.QTimer.singleShot(0, function)
 

labelme/widgets/canvas.py

@@ -26,7 +26,6 @@ class Canvas(QtWidgets.QWidget):
     selectionChanged = QtCore.Signal(list)
     shapeMoved = QtCore.Signal()
     drawingPolygon = QtCore.Signal(bool)
-    edgeSelected = QtCore.Signal(bool, object)
     vertexSelected = QtCore.Signal(bool)
 
     CREATE, EDIT = 0, 1
@@ -181,6 +180,9 @@ class Canvas(QtWidgets.QWidget):
     def selectedVertex(self):
         return self.hVertex is not None
 
+    def selectedEdge(self):
+        return self.hEdge is not None
+
     def mouseMoveEvent(self, ev):
         """Update line with last point and current coordinates."""
         try:
@@ -277,20 +279,34 @@ class Canvas(QtWidgets.QWidget):
                     self.hShape.highlightClear()
                 self.prevhVertex = self.hVertex = index
                 self.prevhShape = self.hShape = shape
-                self.prevhEdge = self.hEdge = index_edge
+                self.prevhEdge = self.hEdge
+                self.hEdge = None
                 shape.highlightVertex(index, shape.MOVE_VERTEX)
                 self.overrideCursor(CURSOR_POINT)
                 self.setToolTip(self.tr("Click & drag to move point"))
                 self.setStatusTip(self.toolTip())
                 self.update()
                 break
-            elif shape.containsPoint(pos):
+            elif index_edge is not None and shape.canAddPoint():
                 if self.selectedVertex():
                     self.hShape.highlightClear()
                 self.prevhVertex = self.hVertex
                 self.hVertex = None
                 self.prevhShape = self.hShape = shape
                 self.prevhEdge = self.hEdge = index_edge
+                self.overrideCursor(CURSOR_POINT)
+                self.setToolTip(self.tr("Click to create point"))
+                self.setStatusTip(self.toolTip())
+                self.update()
+                break
+            elif shape.containsPoint(pos):
+                if self.selectedVertex():
+                    self.hShape.highlightClear()
+                self.prevhVertex = self.hVertex
+                self.hVertex = None
+                self.prevhShape = self.hShape = shape
+                self.prevhEdge = self.hEdge
+                self.hEdge = None
                 self.setToolTip(
                     self.tr("Click & drag to move shape '%s'") % shape.label
                 )
@@ -300,7 +316,6 @@ class Canvas(QtWidgets.QWidget):
                 break
         else:  # Nothing found, clear highlights, reset state.
             self.unHighlight()
-        self.edgeSelected.emit(self.hEdge is not None, self.hShape)
         self.vertexSelected.emit(self.hVertex is not None)
 
     def addPointToEdge(self):
@@ -365,7 +380,10 @@ class Canvas(QtWidgets.QWidget):
                         self.setHiding()
                         self.drawingPolygon.emit(True)
                         self.update()
-            else:
+            elif self.editing():
+                if self.selectedEdge():
+                    self.addPointToEdge()
+
                 group_mode = int(ev.modifiers()) == QtCore.Qt.ControlModifier
                 self.selectShapePoint(pos, multiple_selection_mode=group_mode)
                 self.prevPoint = pos
@@ -387,14 +405,6 @@ class Canvas(QtWidgets.QWidget):
                 # Cancel the move by deleting the shadow copy.
                 self.selectedShapesCopy = []
                 self.repaint()
-        elif ev.button() == QtCore.Qt.LeftButton and self.selectedShapes:
-            self.overrideCursor(CURSOR_GRAB)
-            if (
-                self.editing()
-                and int(ev.modifiers()) == QtCore.Qt.ShiftModifier
-            ):
-                # Add point to line if: left-click + SHIFT on a line segment
-                self.addPointToEdge()
         elif ev.button() == QtCore.Qt.LeftButton and self.selectedVertex():
             if (
                 self.editing()