Pencil: support multiple lines with Shift+click (#1387)

src/app/ui/editor/drawing_state.cpp

@@ -128,6 +128,12 @@ bool DrawingState::onMouseUp(Editor* editor, MouseMessage* msg)
 
   // Update the timeline. TODO make this state observable by the timeline.
   App::instance()->timeline()->updateUsingEditor(editor);
+
+  // Restart again? Here we handle the case to draw multiple lines
+  // using Shift+click with the Pencil tool. When we release the mouse
+  // button, if the Shift key is pressed, the whole ToolLoop starts
+  // again.
+  checkStartDrawingStraightLine(editor);
   return true;
 }
 

src/app/ui/editor/standby_state.cpp

@@ -487,22 +487,8 @@ bool StandbyState::onSetCursor(Editor* editor, const gfx::Point& mouseScreenPos)
 
 bool StandbyState::onKeyDown(Editor* editor, KeyMessage* msg)
 {
-  // Start line preview with shift key
-  if (editor->startStraightLineWithFreehandTool()) {
-    DrawingState* drawingState =
-      startDrawingState(editor,
-                        DrawingType::LineFreehand,
-                        tools::Pointer(
-                          editor->document()->lastDrawingPoint(),
-                          tools::Pointer::Left));
-    if (drawingState) {
-      drawingState->sendMovementToToolLoop(
-        tools::Pointer(
-          editor->screenToEditor(ui::get_mouse_position()),
-          tools::Pointer::Left));
-      return true;
-    }
-  }
+  if (checkStartDrawingStraightLine(editor))
+    return true;
   return false;
 }
 
@@ -621,6 +607,27 @@ DrawingState* StandbyState::startDrawingState(Editor* editor,
   return static_cast<DrawingState*>(newState.get());
 }
 
+bool StandbyState::checkStartDrawingStraightLine(Editor* editor)
+{
+  // Start line preview with shift key
+  if (editor->startStraightLineWithFreehandTool()) {
+    DrawingState* drawingState =
+      startDrawingState(editor,
+                        DrawingType::LineFreehand,
+                        tools::Pointer(
+                          editor->document()->lastDrawingPoint(),
+                          tools::Pointer::Left));
+    if (drawingState) {
+      drawingState->sendMovementToToolLoop(
+        tools::Pointer(
+          editor->screenToEditor(ui::get_mouse_position()),
+          tools::Pointer::Left));
+      return true;
+    }
+  }
+  return false;
+}
+
 Transformation StandbyState::getTransformation(Editor* editor)
 {
   Transformation t = editor->document()->getTransformation();

src/app/ui/editor/standby_state.h

@@ -50,6 +50,7 @@ namespace app {
 
   protected:
     void callEyedropper(Editor* editor);
+    bool checkStartDrawingStraightLine(Editor* editor);
 
     class Decorator : public EditorDecorator {
     public: