[PATCH 1/2] ui/gtk: Add keep-aspect-ratio option

[Weifeng Liu]

When aspect ratio of host window and that of guest display are not
aligned, we can either zoom the guest content to fill the whole host
window or add padding to respect aspect ratio of the guest. Add an
option keep-aspect-ratio to allow users to select their preferred
behavior in this case.

Suggested-by: BALATON Zoltan <bala...@eik.bme.hu>
Suggested-by: Kim, Dongwon <dongwon....@intel.com>
Signed-off-by: Weifeng Liu <weifeng.li...@gmail.com>
---
 include/ui/gtk.h |  1 +
 qapi/ui.json     | 12 ++++++++----
 ui/gtk.c         | 12 ++++++++++--
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/include/ui/gtk.h b/include/ui/gtk.h
index d3944046db..b7cfbf218e 100644
--- a/include/ui/gtk.h
+++ b/include/ui/gtk.h
@@ -140,6 +140,7 @@ struct GtkDisplayState {
     GdkCursor *null_cursor;
     Notifier mouse_mode_notifier;
     gboolean free_scale;
+    gboolean keep_aspect_ratio;
 
     bool external_pause_update;
 
diff --git a/qapi/ui.json b/qapi/ui.json
index 3d0c853c9a..4f7d994e26 100644
--- a/qapi/ui.json
+++ b/qapi/ui.json
@@ -1335,13 +1335,17 @@
 # @show-menubar: Display the main window menubar.  Defaults to "on".
 #     (Since 8.0)
 #
+# @keep-aspect-ratio: Keep width/height aspect ratio of guest content when
+#     resizing host window.  Defaults to "on". (Since 10.1)
+#
 # Since: 2.12
 ##
 { 'struct'  : 'DisplayGTK',
-  'data'    : { '*grab-on-hover' : 'bool',
-                '*zoom-to-fit'   : 'bool',
-                '*show-tabs'     : 'bool',
-                '*show-menubar'  : 'bool'  } }
+  'data'    : { '*grab-on-hover'     : 'bool',
+                '*zoom-to-fit'       : 'bool',
+                '*show-tabs'         : 'bool',
+                '*show-menubar'      : 'bool',
+                '*keep-aspect-ratio' : 'bool'  } }
 
 ##
 # @DisplayEGLHeadless:
diff --git a/ui/gtk.c b/ui/gtk.c
index 8c4a94c8f6..9104509ee1 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -828,8 +828,12 @@ void gd_update_scale(VirtualConsole *vc, int ww, int wh, 
int fbw, int fbh)
 
         sx = (double)ww / fbw;
         sy = (double)wh / fbh;
-
-        vc->gfx.scale_x = vc->gfx.scale_y = MIN(sx, sy);
+        if (vc->s->keep_aspect_ratio) {
+            vc->gfx.scale_x = vc->gfx.scale_y = MIN(sx, sy);
+        } else {
+            vc->gfx.scale_x = sx;
+            vc->gfx.scale_y = sy;
+        }
     }
 }
 /**
@@ -2328,6 +2332,10 @@ static GSList *gd_vc_gfx_init(GtkDisplayState *s, 
VirtualConsole *vc,
         s->free_scale = true;
     }
 
+    s->keep_aspect_ratio = true;
+    if (s->opts->u.gtk.has_keep_aspect_ratio)
+        s->keep_aspect_ratio = s->opts->u.gtk.keep_aspect_ratio;
+
     for (i = 0; i < INPUT_EVENT_SLOTS_MAX; i++) {
         struct touch_slot *slot = &touch_slots[i];
         slot->tracking_id = -1;
-- 
2.49.0