better positioning logic

When asking for a specific layout direction, try very hard at all the
cells that are available in that given direction instead of always
start to compute at a new row and wrong column

components/containmentlayoutmanager/appletslayout.cpp

@@ -370,12 +370,13 @@ void AppletsLayout::showPlaceHolderAt(const QRectF &geom)
     m_placeHolder->setProperty("opacity", 1);
 }
 
-void AppletsLayout::showPlaceHolderForItem(QQuickItem *item)
+void AppletsLayout::showPlaceHolderForItem(ItemContainer *item)
 {
     if (!m_placeHolder) {
         return;
     }
 
+    m_placeHolder->setPreferredLayoutDirection(item->preferredLayoutDirection());
     m_placeHolder->setPosition(item->position());
     m_placeHolder->setSize(item->size());
 

components/containmentlayoutmanager/appletslayout.h

@@ -130,7 +130,7 @@ public:
 
     Q_INVOKABLE void save();
     Q_INVOKABLE void showPlaceHolderAt(const QRectF &geom);
-    Q_INVOKABLE void showPlaceHolderForItem(QQuickItem *item);
+    Q_INVOKABLE void showPlaceHolderForItem(ItemContainer *item);
     Q_INVOKABLE void hidePlaceHolder();
 
     Q_INVOKABLE bool isRectAvailable(qreal x, qreal y, qreal width, qreal height);

components/containmentlayoutmanager/gridlayoutmanager.cpp

@@ -412,6 +412,42 @@ QPair<int, int> GridLayoutManager::nextAvailableCell(const QPair<int, int> &cell
     return QPair<int, int>(-1, -1);
 }
 
+QPair<int, int> GridLayoutManager::nextTakenCell(const QPair<int, int> &cell, AppletsLayout::PreferredLayoutDirection direction) const
+{
+    QPair<int, int> nCell = cell;
+    while (!isOutOfBounds(nCell)) {
+        nCell = nextCell(nCell, direction);
+
+        if (isOutOfBounds(nCell)) {
+            switch (direction) {
+            case AppletsLayout::AppletsLayout::BottomToTop:
+                nCell.first = rows() - 1;
+                --nCell.second;
+                break;
+            case AppletsLayout::AppletsLayout::TopToBottom:
+                nCell.first = 0;
+                ++nCell.second;
+                break;
+            case AppletsLayout::AppletsLayout::RightToLeft:
+                --nCell.first;
+                nCell.second = columns() - 1;
+                break;
+            case AppletsLayout::AppletsLayout::LeftToRight:
+            default:
+                ++nCell.first;
+                nCell.second = 0;
+                break;
+            }
+        }
+
+        if (!isCellAvailable(nCell)) {
+            return nCell;
+        }
+    }
+
+    return QPair<int, int>(-1, -1);
+}
+
 int GridLayoutManager::freeSpaceInDirection(const QPair<int, int> &cell, AppletsLayout::PreferredLayoutDirection direction) const
 {
     QPair<int, int> nCell = cell;
@@ -447,11 +483,11 @@ QRectF GridLayoutManager::nextAvailableSpace(ItemContainer *item, const QSizeF &
         cell.first += itemCellGeom.height();
     }
 
-    while (!isOutOfBounds(cell)) {
+    if (!isCellAvailable(cell)) {
+        cell = nextAvailableCell(cell, direction);
+    }
 
-        if (!isCellAvailable(cell)) {
+    while (!isOutOfBounds(cell)) {
-            cell = nextAvailableCell(cell, direction);
-        }
 
         if (direction == AppletsLayout::LeftToRight || direction == AppletsLayout::RightToLeft) {
             partialSize = QSize(INT_MAX, 0);
@@ -494,7 +530,7 @@ QRectF GridLayoutManager::nextAvailableSpace(ItemContainer *item, const QSizeF &
                         width, height);
                 }
             } else {
-                cell.first = currentRow + 1;
+                cell = nextAvailableCell(nextTakenCell(cell, direction), direction);
             }
 
         } else if (direction == AppletsLayout::TopToBottom || direction == AppletsLayout::BottomToTop) {
@@ -538,7 +574,7 @@ QRectF GridLayoutManager::nextAvailableSpace(ItemContainer *item, const QSizeF &
                         width, height);
                 }
             } else {
-                cell.second = currentColumn + 1;
+                cell = nextAvailableCell(nextTakenCell(cell, direction), direction);
             }
         }
     }

components/containmentlayoutmanager/gridlayoutmanager.h

@@ -94,6 +94,9 @@ private:
     // The next cell that is available given the direction
     QPair<int, int> nextAvailableCell(const QPair<int, int> &cell, AppletsLayout::PreferredLayoutDirection direction) const;
 
+    // The next cell that is has something in it given the direction
+    QPair<int, int> nextTakenCell(const QPair<int, int> &cell, AppletsLayout::PreferredLayoutDirection direction) const;
+
     // How many cells are available in the row starting from the given cell and direction
     int freeSpaceInDirection(const QPair<int, int> &cell, AppletsLayout::PreferredLayoutDirection direction) const;