From b4be993d2f3ebe6b11bba1283db5933e18a89fd2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9a=20Saviot?= <lea.saviot@numworks.com>
Date: Tue, 17 Apr 2018 10:59:06 +0200
Subject: [PATCH] [poincare] Check children when moving vertically in
 HorizontalLayout

Change-Id: Ib0fa5ef58b605c16079e46040a28c96695dcf3d5
---
 poincare/src/layout/horizontal_layout.cpp | 36 ++++++++++++++++-------
 poincare/src/layout/horizontal_layout.h   |  2 ++
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/poincare/src/layout/horizontal_layout.cpp b/poincare/src/layout/horizontal_layout.cpp
index 29be089e5..aa0a30053 100644
--- a/poincare/src/layout/horizontal_layout.cpp
+++ b/poincare/src/layout/horizontal_layout.cpp
@@ -1,6 +1,5 @@
 #include "horizontal_layout.h"
 #include "empty_layout.h"
-#include <poincare/expression_layout_cursor.h>
 extern "C" {
 #include <assert.h>
 #include <kandinsky.h>
@@ -424,18 +423,17 @@ bool HorizontalLayout::moveVertically(ExpressionLayout::VerticalDirection direct
       newPosition = ExpressionLayoutCursor::Position::Left;
     }
     if (brother && cursor->positionIsEquivalentTo(brother, newPosition)) {
-      ExpressionLayout * previousPointedLayout = cursor->pointedExpressionLayout();
-      ExpressionLayoutCursor::Position previousPosition = cursor->position();
-      cursor->setPointedExpressionLayout(brother);
-      cursor->setPosition(newPosition);
-      if (direction == ExpressionLayout::VerticalDirection::Up && brother->moveUp(cursor, shouldRecomputeLayout, this, previousLayout)) {
+      if (tryMoveVerticallyFromAnotherLayout(brother, newPosition, direction, cursor, shouldRecomputeLayout, previousLayout)) {
         return true;
       }
-      if (direction == ExpressionLayout::VerticalDirection::Down && brother->moveDown(cursor, shouldRecomputeLayout, this, previousLayout)) {
-        return true;
-      }
-      cursor->setPointedExpressionLayout(previousPointedLayout);
-      cursor->setPosition(previousPosition);
+    }
+  }
+  /* If the cursor is Lefit or Right of the HorizontalLayout, try moving it up
+   * from its extremal child. */
+  if (cursor->pointedExpressionLayout() == this && previousLayout == nullptr) {
+    int indexOfChildToCheck = cursor->position() == ExpressionLayoutCursor::Position::Left ? 0 : numberOfChildren() - 1;
+    if (tryMoveVerticallyFromAnotherLayout(editableChild(indexOfChildToCheck), cursor->position(), direction, cursor, shouldRecomputeLayout, previousLayout)) {
+      return true;
     }
   }
   if (direction == ExpressionLayout::VerticalDirection::Up) {
@@ -445,6 +443,22 @@ bool HorizontalLayout::moveVertically(ExpressionLayout::VerticalDirection direct
   return ExpressionLayout::moveDown(cursor, shouldRecomputeLayout, previousLayout, previousPreviousLayout);
 }
 
+bool HorizontalLayout::tryMoveVerticallyFromAnotherLayout(ExpressionLayout * otherLayout, ExpressionLayoutCursor::Position otherPosition, ExpressionLayout::VerticalDirection direction, ExpressionLayoutCursor * cursor, bool * shouldRecomputeLayout, ExpressionLayout * previousLayout) {
+  ExpressionLayout * previousPointedLayout = cursor->pointedExpressionLayout();
+  ExpressionLayoutCursor::Position previousPosition = cursor->position();
+  cursor->setPointedExpressionLayout(otherLayout);
+  cursor->setPosition(otherPosition);
+  if (direction == ExpressionLayout::VerticalDirection::Up && otherLayout->moveUp(cursor, shouldRecomputeLayout, this, previousLayout)) {
+    return true;
+  }
+  if (direction == ExpressionLayout::VerticalDirection::Down && otherLayout->moveDown(cursor, shouldRecomputeLayout, this, previousLayout)) {
+    return true;
+  }
+  cursor->setPointedExpressionLayout(previousPointedLayout);
+  cursor->setPosition(previousPosition);
+  return false;
+}
+
 void HorizontalLayout::privateRemoveChildAtIndex(int index, bool deleteAfterRemoval, bool forceRemove) {
   // If the child to remove is at index 0 and its right brother must have a left
   // brother (e.g. it is a VerticalOffsetLayout), replace the child with an
diff --git a/poincare/src/layout/horizontal_layout.h b/poincare/src/layout/horizontal_layout.h
index f194d5376..d69cd0daf 100644
--- a/poincare/src/layout/horizontal_layout.h
+++ b/poincare/src/layout/horizontal_layout.h
@@ -3,6 +3,7 @@
 
 #include <poincare/dynamic_layout_hierarchy.h>
 #include <poincare/layout_engine.h>
+#include <poincare/expression_layout_cursor.h>
 
 namespace Poincare {
 
@@ -48,6 +49,7 @@ protected:
   void privateAddBrother(ExpressionLayoutCursor * cursor, ExpressionLayout * brother, bool moveCursor) override;
 private:
   bool moveVertically(ExpressionLayout::VerticalDirection direction, ExpressionLayoutCursor * cursor, bool * shouldRecomputeLayout, ExpressionLayout * previousLayout, ExpressionLayout * previousPreviousLayout);
+  bool tryMoveVerticallyFromAnotherLayout(ExpressionLayout * otherLayout, ExpressionLayoutCursor::Position otherPosition, ExpressionLayout::VerticalDirection direction, ExpressionLayoutCursor * cursor, bool * shouldRecomputeLayout, ExpressionLayout * previousLayout);
   void privateReplaceChild(const ExpressionLayout * oldChild, ExpressionLayout * newChild, bool deleteOldChild, ExpressionLayoutCursor * cursor);
   void privateRemoveChildAtIndex(int index, bool deleteAfterRemoval, bool forceRemove);
   int removeEmptyChildBeforeInsertionAtIndex(int index, bool shouldRemoveOnLeft);