workspace: Make window preview overlays overflow the allocation

We want to use as much space as possible for showing window previews in
the overview, and the title and close buttons of those windows are only
visible on hover, so we can show them above anything if we want.

On both primary monitors and secondary monitors, there's a certain free
space available towards the bottom edge of the monitor (on the primary
monitor we show the dash there, and secondary monitors just scale down
the Workspaces). We can make use of this by checking how much free space
there is available from the bottom edge of our allocation to the bottom
edge of the monitor, and then aligning the window previews to make full
use of this space.

So stop adding any padding to the edges of the Workspace, which will
make the windows a lot larger and completely fill the Workspaces
allocation.

The left, top and right monitor edges should always be far enough away
to accomodate the close button and hover scale-up of the window. Only
with the bottom edge of the monitor we have to be a bit more careful
(the overflowing height of the window title is quite big), so there we
check if enough free space is available. If there isn't enough free
space, we simply apply a bit of bottom padding again and shift the
window up.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1813>

diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index 2d6764dc41819b6053fb1931c7c84a0723cce864..368f2f31ab043ec6b58fd5ae8e1a2880606cb427 100644 (file)
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -476,13 +476,18 @@ var WorkspaceLayout = GObject.registerClass({
             colSpacing += oversize;
 
         if (containerBox) {
-            const [topOverlap, bottomOverlap] = window.overlapHeights();
-            const overlap = Math.max(topOverlap, bottomOverlap);
+            const monitor = Main.layoutManager.monitors[this._monitorIndex];
 
-            containerBox.x1 += oversize;
-            containerBox.x2 -= oversize;
-            containerBox.y1 += oversize + overlap;
-            containerBox.y2 -= oversize + overlap;
+            const bottomPoint = new Graphene.Point3D({ y: containerBox.y2 });
+            const transformedBottomPoint =
+                this._container.apply_transform_to_point(bottomPoint);
+            const bottomFreeSpace =
+                (monitor.y + monitor.height) - transformedBottomPoint.y;
+
+            const [, bottomOverlap] = window.overlapHeights();
+
+            if ((bottomOverlap + oversize) > bottomFreeSpace)
+                containerBox.y2 -= (bottomOverlap + oversize) - bottomFreeSpace;
         }
 
         return [rowSpacing, colSpacing, containerBox];