console: Fix resize_to_vm with host fractional scaling

Trying to size the window based on VM desktop resolution does
not do the correct thing when host fractional scaling is enabled
and using spice.

The best we can do here is ask the viewer widget for its
preferred size

Signed-off-by: Cole Robinson <crobinso@redhat.com>

tests/uitests/test_livetests.py

@@ -152,15 +152,22 @@ def _checkConsoleStandard(app, dom):
     win.find("^View$", "menu").click()
     scalemenu = win.find("Scale Display", "menu")
     scalemenu.point()
-    scalemenu.find("Always", "radio menu item").click()
-    win.find("^View$", "menu").click()
-    scalemenu = win.find("Scale Display", "menu")
-    scalemenu.point()
     scalemenu.find("Never", "radio menu item").click()
     win.find("^View$", "menu").click()
     scalemenu = win.find("Scale Display", "menu")
     scalemenu.point()
     scalemenu.find("Only", "radio menu item").click()
+    win.find("^View$", "menu").click()
+    scalemenu = win.find("Scale Display", "menu")
+    scalemenu.point()
+    scalemenu.find("Always", "radio menu item").click()
+
+    # 'Resize to VM' again, to hit the scaling->always case
+    oldsize = win.size
+    win.find("^View$", "menu").click()
+    win.find("Resize to VM", "menu item").click()
+    newsize = win.size
+    lib.utils.check(lambda: oldsize != newsize)
 
     win.window_close()
 

virtManager/details/console.py

@@ -480,27 +480,22 @@ class vmmConsolePages(vmmGObjectUI):
         self._viewer.console_set_resizeguest(val)
 
     def _set_size_to_vm(self):
-        # Resize the console to best fit the VM resolution
-        vm_resolution = self._viewer.console_get_desktop_resolution()
-        if not self._viewer:
+        if not self._viewer_is_visible():
             return  # pragma: no cover
-        if not vm_resolution:  # pragma: no cover
-            log.debug("_set_size_to_vm but no VM desktop resolution set")
-            return
 
-        # Note: gtk3 has no APIs for telling us about fractional scaling.
-        # without that, we can't reliably figure out how VM dimensions
-        # should map to host widget dimensions.
+        w, h = self._viewer.console_get_preferred_size()
+        if w <= 0 or h <= 0:  # pragma: no cover
+            log.debug("_set_size_to_vm but no valid sizing found")
+            return
 
         top_w, top_h = self.topwin.get_size()
         viewer_alloc = self.widget("console-gfx-scroll").get_allocation()
-        desktop_w, desktop_h = vm_resolution
 
-        valw = desktop_w + (top_w - viewer_alloc.width)
-        valh = desktop_h + (top_h - viewer_alloc.height)
+        valw = w + (top_w - viewer_alloc.width)
+        valh = h + (top_h - viewer_alloc.height)
 
         log.debug("_set_size_to_vm vm=(%s, %s) window=(%s, %s)",
-                  desktop_w, desktop_h, valw, valh)
+                  w, h, valw, valh)
         self.topwin.unmaximize()
         self.topwin.resize(valw, valh)
 

virtManager/details/viewers.py

@@ -76,7 +76,7 @@ class Viewer(vmmGObject):
         self._ginfo = ginfo
         self._tunnels = SSHTunnels(self._ginfo)
         self._keyboard_grab = False
-        self._desktop_resolution = None
+        self._desktop_resolution = (0, 0)
 
         self.add_gsettings_handle(
             self.config.on_keys_combination_changed(self._refresh_grab_keys))
@@ -202,12 +202,6 @@ class Viewer(vmmGObject):
         self._desktop_resolution = newres
         self.emit("desktop-resolution-changed")
 
-    def _get_desktop_resolution(self):
-        ret = self._desktop_resolution or (0, 0)
-        if (ret[0] == 0) or (ret[1] == 0):
-            return None
-        return ret
-
 
     #######################################################
     # Internal API that will be overwritten by subclasses #
@@ -254,6 +248,9 @@ class Viewer(vmmGObject):
     def _has_usb_redirection(self):
         raise NotImplementedError()
 
+    def _get_preferred_size(self):
+        raise NotImplementedError()
+
 
     ####################################
     # APIs accessed by vmmConsolePages #
@@ -284,8 +281,8 @@ class Viewer(vmmGObject):
     def console_get_grab_keys(self):
         return self._get_grab_keys()
 
-    def console_get_desktop_resolution(self):
-        return self._get_desktop_resolution()
+    def console_get_preferred_size(self):
+        return self._get_preferred_size()
 
     def console_set_scaling(self, val):
         return self._set_scaling(val)
@@ -445,6 +442,9 @@ class VNCViewer(Viewer):
     def _has_usb_redirection(self):
         return False
 
+    def _get_preferred_size(self):
+        return self._desktop_resolution
+
 
     #######################
     # Connection routines #
@@ -758,3 +758,16 @@ class SpiceViewer(Viewer):
         if not self._spice_session or not self._usbdev_manager:
             return False  # pragma: no cover
         return True
+
+    def _get_preferred_size(self):
+        if (not self._display or
+            self._get_scaling() or
+            self._get_resizeguest()):
+            return self._desktop_resolution
+
+        # When scaling and resizeguest disabled, this usually matches the
+        # VM resolution. But when host desktop scaling is used, spice will
+        # intentionally have different values here.
+        w = self._display.get_preferred_width()[1]
+        h = self._display.get_preferred_height()[1]
+        return (w, h)