Overview: apply extra padding to windows in external monitor

Add an style class targetting workspaces located outside the overview,
and use it for extra padding around the window clones. Padding is passed
down and applied inside LayoutStrategy, consolidating code that previously
handled the bottom side only.

https://bugzilla.gnome.org/show_bug.cgi?id=690171

data/theme/gnome-shell.css

@@ -727,6 +727,10 @@ StScrollBar StButton#vhandle:active {
     -vertical-spacing: 32px;
 }
 
+.window-picker.external-monitor {
+    padding: 32px;
+}
+
 /* Dash */
 
 #dash {
@@ -751,10 +755,6 @@ StScrollBar StButton#vhandle:active {
     height: 24px;
 }
 
-#viewSelector {
-    spacing: 1em;
-}
-
 /* Search Box */
 
 #searchEntry {

js/ui/workspace.js

@@ -746,11 +746,10 @@ const LayoutStrategy = new Lang.Class({
     Name: 'LayoutStrategy',
     Abstract: true,
 
-    _init: function(monitor, rowSpacing, columnSpacing, bottomPadding) {
+    _init: function(monitor, rowSpacing, columnSpacing) {
         this._monitor = monitor;
         this._rowSpacing = rowSpacing;
         this._columnSpacing = columnSpacing;
-        this._bottomPadding = bottomPadding;
     },
 
     _newRow: function() {
@@ -830,7 +829,7 @@ const LayoutStrategy = new Lang.Class({
         let area = layout.area;
 
         let hspacing = (layout.maxColumns - 1) * this._columnSpacing;
-        let vspacing = (layout.numRows - 1) * this._rowSpacing + this._bottomPadding;
+        let vspacing = (layout.numRows - 1) * this._rowSpacing;
 
         let spacedWidth = area.width - hspacing;
         let spacedHeight = area.height - vspacing;
@@ -864,7 +863,7 @@ const LayoutStrategy = new Lang.Class({
             y += row.height + this._rowSpacing;
         }
 
-        let height = y - this._rowSpacing + this._bottomPadding;
+        let height = y - this._rowSpacing;
         let baseY = (area.height - height) / 2;
 
         for (let i = 0; i < rows.length; i++) {
@@ -1038,6 +1037,8 @@ const Workspace = new Lang.Class({
         this._windowOverlaysGroup.set_size(0, 0);
 
         this.actor = new St.Widget({ style_class: 'window-picker' });
+        if (monitorIndex != Main.layoutManager.primaryIndex)
+            this.actor.add_style_class_name('external-monitor');
         this.actor.set_size(0, 0);
 
         this._dropRect = new Clutter.Rectangle({ opacity: 0 });
@@ -1624,7 +1625,7 @@ const Workspace = new Lang.Class({
         }
     },
 
-    _computeLayout: function(windows, area, rowSpacing, columnSpacing, bottomPadding) {
+    _computeLayout: function(windows, area, rowSpacing, columnSpacing) {
         // We look for the largest scale that allows us to fit the
         // largest row/tallest column on the workspace.
 
@@ -1640,7 +1641,7 @@ const Workspace = new Lang.Class({
                 break;
 
             let strategyClass = numRows > 2 ? GridLayoutStrategy : UnalignedLayoutStrategy;
-            let strategy = new strategyClass(this._monitor, rowSpacing, columnSpacing, bottomPadding);
+            let strategy = new strategyClass(this._monitor, rowSpacing, columnSpacing);
 
             let layout = { area: area, strategy: strategy, numRows: numRows, numColumns: numColumns };
             strategy.computeLayout(windows, layout);
@@ -1672,6 +1673,12 @@ const Workspace = new Lang.Class({
         // Window grid spacing
         let columnSpacing = node.get_length('-horizontal-spacing');
         let rowSpacing = node.get_length('-vertical-spacing');
+        let padding = {
+            left: node.get_padding(St.Side.LEFT),
+            top: node.get_padding(St.Side.TOP),
+            bottom: node.get_padding(St.Side.BOTTOM),
+            right: node.get_padding(St.Side.RIGHT),
+        };
 
         if (!totalWindows)
             return [];
@@ -1686,19 +1693,25 @@ const Workspace = new Lang.Class({
             [leftBorder, rightBorder] = overlay.chromeWidths();
         } else {
             [closeButtonHeight, captionHeight] = [0, 0];
+            [leftBorder, rightBorder] = [0, 0];
         }
 
         rowSpacing += captionHeight;
-        columnSpacing += rightBorder;
+        columnSpacing += (rightBorder + leftBorder) / 2;
+        padding.top += closeButtonHeight;
+        padding.bottom += captionHeight;
+        padding.left += leftBorder;
+        padding.right += rightBorder;
 
-        let area = { x: this._x, y: this._y, width: this._width, height: this._height };
+        let area = {
-        area.y += closeButtonHeight;
+            x: this._x + padding.left,
-        area.height -= closeButtonHeight;
+            y: this._y + padding.top,
-        area.x += leftBorder;
+            width: this._width - padding.left - padding.right,
-        area.width -= leftBorder;
+            height: this._height - padding.top - padding.bottom,
+        };
 
         if (!this._currentLayout)
-            this._currentLayout = this._computeLayout(windows, area, rowSpacing, columnSpacing, captionHeight);
+            this._currentLayout = this._computeLayout(windows, area, rowSpacing, columnSpacing);
 
         let layout = this._currentLayout;
         let strategy = layout.strategy;