iconGrid: Add PaginatedIconGrid

The new PaginatedIconGrid class acts as a container for pages.
So the new class provides  the container behaviour and some
useful functions like positions of pages, number of pages, etc.
But, it doesn't add indicators of the pages and doesn't manage
the scroll of the pages, neither any management of the pages
like in which page currently it is, etc.

https://bugzilla.gnome.org/show_bug.cgi?id=706081

diff --git a/js/ui/iconGrid.js b/js/ui/iconGrid.js
index 9ed82ba5f591c04394b753a2a56569f35f622dac..a5c16f09842144c637e914fd6dcb9d8343162127 100644 (file)
--- a/js/ui/iconGrid.js
+++ b/js/ui/iconGrid.js
@@ -400,5 +400,109 @@ const IconGrid = new Lang.Class({
             spacing = Math.round(spacing);
         }
         this.setSpacing(spacing);
+    },
+});
+
+const PaginatedIconGrid = new Lang.Class({
+    Name: 'PaginatedIconGrid',
+    Extends: IconGrid,
+
+    _init: function(params) {
+        this.parent(params);
+        this._nPages = 0;
+    },
+
+    _getPreferredHeight: function (grid, forWidth, alloc) {
+        alloc.min_size = this._availableHeightPerPageForItems() * this._nPages + this._spaceBetweenPages * this._nPages;
+        alloc.natural_size = this._availableHeightPerPageForItems() * this._nPages + this._spaceBetweenPages * this._nPages;
+    },
+
+    _allocate: function (grid, box, flags) {
+         if (this._childrenPerPage == 0)
+            log('computePages() must be called before allocate(); pagination will not work.');
+
+        if (this._fillParent) {
+            // Reset the passed in box to fill the parent
+            let parentBox = this.actor.get_parent().allocation;
+            let gridBox = this.actor.get_theme_node().get_content_box(parentBox);
+            box = this._grid.get_theme_node().get_content_box(gridBox);
+        }
+        let children = this._getVisibleChildren();
+        let availWidth = box.x2 - box.x1;
+        let availHeight = box.y2 - box.y1;
+        let spacing = this._getSpacing();
+        let [nColumns, usedWidth] = this._computeLayout(availWidth);
+
+        let leftPadding;
+        switch(this._xAlign) {
+            case St.Align.START:
+                leftPadding = 0;
+                break;
+            case St.Align.MIDDLE:
+                leftPadding = Math.floor((availWidth - usedWidth) / 2);
+                break;
+            case St.Align.END:
+                leftPadding = availWidth - usedWidth;
+        }
+
+        let x = box.x1 + leftPadding;
+        let y = box.y1;
+        let columnIndex = 0;
+        let rowIndex = 0;
+
+        for (let i = 0; i < children.length; i++) {
+            let childBox = this._calculateChildBox(children[i], x, y, box);
+            children[i].allocate(childBox, flags);
+            this._grid.set_skip_paint(children[i], false);
+
+            columnIndex++;
+            if (columnIndex == nColumns) {
+                columnIndex = 0;
+                rowIndex++;
+            }
+            if (columnIndex == 0) {
+                y += this._vItemSize + spacing;
+                if ((i + 1) % this._childrenPerPage == 0)
+                    y += this._spaceBetweenPages - spacing;
+                x = box.x1 + leftPadding;
+            } else {
+                x += this._hItemSize + spacing;
+            }
+        }
+    },
+
+    computePages: function (availWidthPerPage, availHeightPerPage) {
+        let [nColumns, usedWidth] = this._computeLayout(availWidthPerPage);
+        let nRows;
+        let children = this._getVisibleChildren();
+        if (nColumns > 0)
+            nRows = Math.ceil(children.length / nColumns);
+        else
+            nRows = 0;
+        if (this._rowLimit)
+            nRows = Math.min(nRows, this._rowLimit);
+
+        let spacing = this._getSpacing();
+        this._rowsPerPage = Math.floor((availHeightPerPage + spacing) / (this._vItemSize + spacing));
+        this._nPages = Math.ceil(nRows / this._rowsPerPage);
+        this._spaceBetweenPages = availHeightPerPage - (this._rowsPerPage * (this._vItemSize + spacing) - spacing);
+        this._childrenPerPage = nColumns * this._rowsPerPage;
+    },
+
+    _availableHeightPerPageForItems: function() {
+        return this._rowsPerPage * this._vItemSize + (this._rowsPerPage - 1) * this._getSpacing();
+    },
+
+    nPages: function() {
+        return this._nPages;
+    },
+
+    getPageY: function(pageNumber) {
+        if (!this._nPages)
+            return 0;
+
+        let firstPageItem = pageNumber * this._childrenPerPage
+        let childBox = this._getVisibleChildren()[firstPageItem].get_allocation_box();
+        return childBox.y1;
     }
 });