[gnome-shell/wip/paging-release2: 3/22] iconGrid: Add PaginatedIconGrid

[Carlos Soriano <csoriano src gnome org>]

commit 167fc877b1008890b474a55f9e77ed4b7d2a07d9
Author: Carlos Soriano <carlos soriano89 gmail com>
Date:   Tue Aug 20 10:14:25 2013 +0200

    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

 js/ui/iconGrid.js |  108 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 108 insertions(+), 0 deletions(-)
---
diff --git a/js/ui/iconGrid.js b/js/ui/iconGrid.js
index 9ed82ba..5368489 100644
--- a/js/ui/iconGrid.js
+++ b/js/ui/iconGrid.js
@@ -363,6 +363,10 @@ const IconGrid = new Lang.Class({
         this._grid.queue_relayout();
     },
 
+    rowHeight: function() {
+        return this._vItemSize + this._getSpacing();
+    },
+
     removeAll: function() {
         this._grid.destroy_all_children();
     },
@@ -400,5 +404,109 @@ 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;
     }
 });