exposay: make inner border dependent of exposay's surfaces size

We've been using an inner border of fixed size (80px), but this
is dangerous. If you have too many open applications or a small
window, the surface size computed will be negative, crashing
the exposay: "error: weston_view transformation not invertible".

Also, it creates a lot of unnecessary space, making the exposay
unusable when we have a small window or many applications open.

Make inner border to be 10% of surface size and surface size to
be 90% of its original size, avoiding the crashes and making it
more visually pleasant.

Signed-off-by: Leandro Ribeiro <leandrohr@riseup.net>

diff --git a/desktop-shell/exposay.c b/desktop-shell/exposay.c
index 7594301a85860d5e0abea9a5e45f9d32f14e85a9..e03a3114d5c20bbebb6f848d34a58654a3b40c15 100644 (file)
--- a/desktop-shell/exposay.c
+++ b/desktop-shell/exposay.c
@@ -207,9 +207,42 @@ handle_view_destroy(struct wl_listener *listener, void *data)
        exposay_surface_destroy(esurface);
 }
 
-/* Pretty lame layout for now; just tries to make a square.  Should take
+/* Compute each surface size and then inner pad (10% of surface size).
+ * After that, it's necessary to recompute surface size (90% of its
+ * original size). Also, each surface can't be bigger than half the
+ * exposay area width and height.
+ */
+static void
+exposay_surface_and_inner_pad_size(pixman_rectangle32_t exposay_area, struct exposay_output *eoutput)
+{
+       if (exposay_area.height < exposay_area.width)
+               eoutput->surface_size =
+                       (exposay_area.height - (eoutput->vpadding_outer * 2)) / eoutput->grid_size;
+       else
+               eoutput->surface_size =
+                       (exposay_area.width - (eoutput->hpadding_outer * 2)) / eoutput->grid_size;
+       eoutput->padding_inner = eoutput->surface_size / 10;
+       eoutput->surface_size -= eoutput->padding_inner;
+
+       if ((uint32_t)eoutput->surface_size > (exposay_area.width / 2))
+               eoutput->surface_size = exposay_area.width / 2;
+       if ((uint32_t)eoutput->surface_size > (exposay_area.height / 2))
+               eoutput->surface_size = exposay_area.height / 2;
+}
+
+/* Pretty lame layout for now; just tries to make a square. Should take
  * aspect ratio into account really.  Also needs to be notified of surface
- * addition and removal and adjust layout/animate accordingly. */
+ * addition and removal and adjust layout/animate accordingly.
+ *
+ * Lay the grid out as square as possible, losing surfaces from the
+ * bottom row if required. Start with fixed padding of a 10% margin
+ * around the outside, and maximise the area made available to surfaces
+ * after this. Also, add an inner padding between surfaces that varies
+ * with the surface size (10% of its size).
+ *
+ * If we can't make a square grid, add one extra row at the bottom which
+ * will have a smaller number of columns.
+ */
 static enum exposay_layout_state
 exposay_layout(struct desktop_shell *shell, struct shell_output *shell_output)
 {
@@ -219,7 +252,6 @@ exposay_layout(struct desktop_shell *shell, struct shell_output *shell_output)
        struct weston_view *view;
        struct exposay_surface *esurface, *highlight = NULL;
        pixman_rectangle32_t exposay_area;
-       int w, h;
        int pad;
        int i;
        int last_row_removed = 0;
@@ -246,40 +278,18 @@ exposay_layout(struct desktop_shell *shell, struct shell_output *shell_output)
         * the shell panel position and size */
        get_output_work_area(shell, output, &exposay_area);
 
-       /* Lay the grid out as square as possible, losing surfaces from the
-        * bottom row if required.  Start with fixed padding of a 10% margin
-        * around the outside and 80px internal padding between surfaces, and
-        * maximise the area made available to surfaces after this, but only
-        * to a maximum of 1/3rd the total output size.
-        *
-        * If we can't make a square grid, add one extra row at the bottom
-        * which will have a smaller number of columns.
-        *
-        * XXX: Surely there has to be a better way to express this maths,
-        *      right?!
-        */
+       /* Compute grid size */
        eoutput->grid_size = floor(sqrtf(eoutput->num_surfaces));
        if (pow(eoutput->grid_size, 2) != eoutput->num_surfaces)
                eoutput->grid_size++;
        last_row_removed = pow(eoutput->grid_size, 2) - eoutput->num_surfaces;
 
+       /* Fixed outer padding of 10% the size of the screen */
        eoutput->hpadding_outer = (exposay_area.width / 10);
        eoutput->vpadding_outer = (exposay_area.height / 10);
-       eoutput->padding_inner = 80;
-
-       w = exposay_area.width - (eoutput->hpadding_outer * 2);
-       w -= eoutput->padding_inner * (eoutput->grid_size - 1);
-       w /= eoutput->grid_size;
 
-       h = exposay_area.height - (eoutput->vpadding_outer * 2);
-       h -= eoutput->padding_inner * (eoutput->grid_size - 1);
-       h /= eoutput->grid_size;
-
-       eoutput->surface_size = (w < h) ? w : h;
-       if ((uint32_t)eoutput->surface_size > (exposay_area.width / 2))
-               eoutput->surface_size = exposay_area.width / 2;
-       if ((uint32_t)eoutput->surface_size > (exposay_area.height / 2))
-               eoutput->surface_size = exposay_area.height / 2;
+       /* Compute each surface size and the inner padding between them */
+       exposay_surface_and_inner_pad_size(exposay_area, eoutput);
 
        pad = eoutput->surface_size + eoutput->padding_inner;