[escher] Add an insertionField in LayoutField

escher/include/escher/layout_field.h

@@ -60,6 +60,7 @@ private:
   void scrollRightOfLayout(Poincare::Layout layoutR);
   void scrollToBaselinedRect(KDRect rect, KDCoordinate baseline);
   void insertLayoutAtCursor(Poincare::Layout layoutR, Poincare::Expression correspondingExpression, bool forceCursorRightOfLayout = false);
+  bool eventShouldUpdateInsertionCursor(Ion::Events::Event event) { return event == Ion::Events::Up; }
 
   class ContentView : public View {
   public:
@@ -83,14 +84,22 @@ private:
     void copySelection(Poincare::Context * context);
     bool selectionIsEmpty() const;
     void deleteSelection();
+    void invalidateInsertionCursor() { m_insertionCursor = Poincare::LayoutCursor(); }
+    void updateInsertionCursor() {
+      if (!m_insertionCursor.isDefined()) {
+        m_insertionCursor = m_cursor;
+      }
+    }
 
   private:
     int numberOfSubviews() const override { return 2; }
     View * subviewAtIndex(int index) override;
     void layoutSubviews(bool force = false) override;
     void layoutCursorSubview(bool force);
+    void useInsertionCursor();
     KDRect selectionRect() const;
     Poincare::LayoutCursor m_cursor;
+    Poincare::LayoutCursor m_insertionCursor;
     ExpressionView m_expressionView;
     TextCursorView m_cursorView;
     /* The selection starts on the left of m_selectionStart, and ends on the

escher/src/layout_field.cpp

@@ -11,6 +11,7 @@ using namespace Poincare;
 
 LayoutField::ContentView::ContentView() :
   m_cursor(),
+  m_insertionCursor(),
   m_expressionView(0.0f, 0.5f, KDColorBlack, KDColorWhite, &m_selectionStart, &m_selectionEnd),
   m_cursorView(),
   m_selectionStart(),
@@ -30,12 +31,21 @@ bool LayoutField::ContentView::setEditing(bool isEditing) {
       m_expressionView.layout().invalidAllSizesPositionsAndBaselines();
       return true;
     }
+  } else {
+    // We're leaving the edition of the current layout
+    useInsertionCursor();
   }
   layoutSubviews();
   markRectAsDirty(bounds());
   return false;
 }
 
+void LayoutField::ContentView::useInsertionCursor() {
+  if (m_insertionCursor.isDefined()) {
+    m_cursor = m_insertionCursor;
+  }
+}
+
 void LayoutField::ContentView::clearLayout() {
   HorizontalLayout h = HorizontalLayout::Builder();
   if (m_expressionView.setLayout(h)) {
@@ -318,6 +328,12 @@ bool LayoutField::handleEventWithText(const char * text, bool indentation, bool
    * - the text added after a toolbox selection
    * - the result of a copy-paste. */
 
+  /* This routing can be called even if no actual underlying event has been
+   * dispatched on the LayoutField. For instance, when someone wants to insert
+   * text in the field from the outside. In this scenario, let's make sure the
+   * insertionCursor is invalidated. */
+  m_contentView.invalidateInsertionCursor();
+
   // Delete the selected layouts if needed
   deleteSelection();
 
@@ -382,6 +398,9 @@ bool LayoutField::handleEvent(Ion::Events::Event event) {
   KDSize previousSize = minimalSizeForOptimalDisplay();
   bool shouldRecomputeLayout = m_contentView.cursor()->showEmptyLayoutIfNeeded();
   bool moveEventChangedLayout = false;
+  if (!eventShouldUpdateInsertionCursor(event)) {
+    m_contentView.invalidateInsertionCursor();
+  }
   if (privateHandleMoveEvent(event, &moveEventChangedLayout)) {
     if (!isEditing()) {
       setEditing(true);
@@ -554,6 +573,9 @@ bool LayoutField::privateHandleMoveEvent(Ion::Events::Event event, bool * should
   LayoutCursor result;
   result = m_contentView.cursor()->cursorAtDirection(DirectionForMoveEvent(event), shouldRecomputeLayout);
   if (result.isDefined()) {
+    if (eventShouldUpdateInsertionCursor(event)) {
+      m_contentView.updateInsertionCursor();
+    }
     m_contentView.setCursor(result);
     return true;
   }