Set Virtual Me2Me desktop's initial DPI to 96

remoting/tools/me2me_virtual_host.py

 #!/usr/bin/python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Virtual Me2Me implementation.  This script runs and manages the processes
 # required for a Virtual Me2Me desktop, which are: X server, X desktop
 # session, and Host process.
 # This script is intended to run continuously as a background daemon
 # process, running under an ordinary (non-root) user account.
@@ skipping 311 matching lines @@
     if retcode != 0:
       logging.error("Failed to set XKB to 'evdev'")
 
     # Register the screen sizes if the X server's RANDR extension supports it.
     # Errors here are non-fatal; the X server will continue to run with the
     # dimensions from the "-screen" option.
     for width, height in self.sizes:
       label = "%dx%d" % (width, height)
       args = ["xrandr", "--newmode", label, "0", str(width), "0", "0", "0",
               str(height), "0", "0", "0"]
-      proc = subprocess.Popen(args, env=self.child_env, stdout=devnull,
-                              stderr=devnull)
-      proc.wait()
+      subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull)

[Lambros, 2013/01/04 22:21:37]

call() takes same args as Popen() so I decided to clean all these up, as well as
the new one I've added.

       args = ["xrandr", "--addmode", "screen", label]
-      proc = subprocess.Popen(args, env=self.child_env, stdout=devnull,
-                              stderr=devnull)
-      proc.wait()
+      subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull)
 
     # Set the initial mode to the first size specified, otherwise the X server
     # would default to (max_width, max_height), which might not even be in the
     # list.
-    label = "%dx%d" % self.sizes[0]
+    (width, height) = self.sizes[0]
+    label = "%dx%d" % (width, height)
     args = ["xrandr", "-s", label]
-    proc = subprocess.Popen(args, env=self.child_env, stdout=devnull,
-                            stderr=devnull)
-    proc.wait()
+    subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull)
+
+    # Set the physical size of the display so that the initial mode is running
+    # at approximately 96 DPI, since some desktops require the DPI to be set to
+    # something realistic.
+    DPI = 96.0
+    MM_PER_INCH = 25.4
+    # width / DPI is width in inches. Multiplying by MM_PER_INCH converts to mm.
+    width_mm = int(width / DPI * MM_PER_INCH)

[Wez, 2013/01/04 22:32:57]

nit: Bracket width / DPI for readability.

+    height_mm = int(height / DPI * MM_PER_INCH)
+    args = ["xrandr", "--fbmm", "%dx%d" % (width_mm, height_mm)]

[Sergey Ulanov, 2013/01/04 22:28:33]

why not use --dpi here?

[Wez, 2013/01/04 23:36:02]

Good point; xrandr --dpi 96/screen should work.

+    subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull)
 
     devnull.close()
 
   def _launch_x_session(self):
     # Start desktop session
     # The /dev/null input redirection is necessary to prevent the X session
     # reading from stdin.  If this code runs as a shell background job in a
     # terminal, any reading from stdin causes the job to be suspended.
     # Daemonization would solve this problem by separating the process from the
     # controlling terminal.
@@ skipping 692 matching lines @@
         host_config.clear_auth()
         host_config.clear_host_info()
         host_config.save()
         return 0
 
 
 if __name__ == "__main__":
   logging.basicConfig(level=logging.DEBUG,
                       format="%(asctime)s:%(levelname)s:%(message)s")
   sys.exit(main())