Choose monitor with GTK dialog

Fixes: QubesOS/qubes-issues#9282

doc/qubes-video-companion.rst

@@ -21,7 +21,7 @@ The project emphasizes correctness and security all the while also sporting supe
 OPTIONS
 =======
 resolution
-    The video resolution to stream and receive video in. The format is [WIDTHxHEIGHTxFPS], meaning resolution is optional. If you set the environment variable "QVC_MONITOR" in the target, that monitor is going to be preferred and if not found, will fallback to the primary monitor. Example: "1920x1080x60"
+    The video resolution to stream and receive video in. The format is [WIDTHxHEIGHTxFPS], meaning resolution is optional. Example: "1920x1080x60"
 
 
 video_source

qubes-rpc/services/qvc.ScreenShare

@@ -5,27 +5,7 @@
 
 set -eu
 
-## DISPLAY variable used by: xrandr, zenity
-export DISPLAY=:0
-
 true "${XDG_RUNTIME_DIR:="/run/user/$(id -u)"}"
 true "${DBUS_SESSION_BUS_ADDRESS:="unix:path=${XDG_RUNTIME_DIR}/bus"}"
-monitors="$(xrandr --listactivemonitors \
-            | awk '/^ [0-9]+: \+/ { print "FALSE", $4, $3 }')"
-monitor_count="$(echo "${monitors}" | wc -l)"
-monitor_longest_line="$(echo "${monitors}" | wc -L)"
-dialog_height="$((monitor_count*50+60))"
-dialog_width="$((monitor_longest_line*10))"
-if test "${monitor_count}" -gt 1; then
-  # shellcheck disable=SC2086
-  QVC_MONITOR="$(zenity --list --radiolist \
-    --height="${dialog_height}" --width="${dialog_width}" \
-    --column "ID" --column "Name" --column "Resolution" \
-    --title "Screen share" \
-    --text "Select monitor to present to qube ${QREXEC_REMOTE_DOMAIN}" \
-    ${monitors})"
-fi
-true "${QVC_MONITOR:=}"
-
-export XDG_RUNTIME_DIR DBUS_SESSION_BUS_ADDRESS QVC_MONITOR
+export DISPLAY=:0 XDG_RUNTIME_DIR DBUS_SESSION_BUS_ADDRESS
 exec python3 -- /usr/share/qubes-video-companion/sender/screenshare.py

receiver/receiver.py

@@ -59,6 +59,11 @@ def read_video_parameters() -> (int, int, int):
         raise AssertionError("bug")
 
     untrusted_input = os.read(0, input_size)
+
+    if len(untrusted_input) == 0:
+        print("Operation canceled by sender", file=sys.stderr)
+        sys.exit(1)
+
     if len(untrusted_input) != input_size:
         raise RuntimeError("wrong number of bytes read")
     untrusted_width, untrusted_height, untrusted_fps = sstruct.unpack(

sender/screenshare.py

@@ -2,6 +2,7 @@
 
 # Copyright (C) 2021 Elliot Killick <[email protected]>
 # Copyright (C) 2021 Demi Marie Obenour <[email protected]>
+# Copyright (C) 2024 Benjamin Grande M. S. <[email protected]>
 # Licensed under the MIT License. See LICENSE file for details.
 
 """Screen sharing video source module"""
@@ -10,10 +11,9 @@
 # pylint: disable=wrong-import-position
 
 import gi
-import os
-
 gi.require_version("Gdk", "3.0")
-from gi.repository import Gdk
+gi.require_version("Gtk", "3.0")
+from gi.repository import Gtk, Gdk, GdkPixbuf
 from service import Service
 from typing import List, Tuple
 
@@ -22,6 +22,7 @@ class ScreenShare(Service):
     """Screen sharing video souce class"""
 
     def __init__(self) -> None:
+        self.selected_monitor_index = None
         self.main(self)
 
     def video_source(self) -> str:
@@ -30,16 +31,92 @@ def video_source(self) -> str:
     def icon(self) -> str:
         return "video-display"
 
-    def parameters(self) -> Tuple[int, int, int]:
+    def monitor_dialog(self) -> None:
         display = Gdk.Display().get_default()
         monitor_count = display.get_n_monitors()
-        monitor_wanted = os.environ["QVC_MONITOR"]
-        ## If wanted monitor is not found, use the primary monitor (0).
-        monitor_index = 0
-        for m in range(monitor_count):
-            if display.get_monitor(m).get_model() == monitor_wanted:
-                monitor_index = m
-                break
+
+        if monitor_count == 1:
+            self.selected_monitor_index = 0
+            return
+
+        combobox = Gtk.ComboBoxText()
+        monitor_screenshots = []
+        for monitor_num in range(monitor_count):
+            monitor_name = display.get_monitor(monitor_num).get_model()
+            monitor = display.get_monitor(monitor_num)
+            monitor_geometry = monitor.get_geometry()
+            monitor_width = monitor_geometry.width
+            monitor_height = monitor_geometry.height
+            monitor_x = monitor_geometry.x
+            monitor_y = monitor_geometry.y
+
+            combobox.append_text(f"{monitor_name}: "
+                                 f"{monitor_width}x{monitor_height} "
+                                 f"{monitor_x}+{monitor_y}")
+
+            pixbuf = Gdk.pixbuf_get_from_window(
+                display.get_default_screen().get_root_window(),
+                monitor_x,
+                monitor_y,
+                monitor_width,
+                monitor_height)
+            pixbuf = pixbuf.scale_simple(
+                min(960, pixbuf.get_width()),
+                min(540, pixbuf.get_height()),
+                GdkPixbuf.InterpType.BILINEAR)
+            monitor_screenshots.append(pixbuf)
+
+        window = Gtk.Window(title="Qubes Screen Share")
+        window.connect("destroy", Gtk.main_quit)
+        vbox = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=6)
+        window.add(vbox)
+
+        ## TODO: add 'remote_domain' to differentiate calls.
+        label = Gtk.Label(label="Select a monitor:")
+        vbox.pack_start(label, False, False, 0)
+        hbox = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL, spacing=6)
+        vbox.pack_start(hbox, False, False, 0)
+
+        ## Select first monitor when opening the dialog.
+        combobox.set_active(0)
+
+        hbox.pack_start(combobox, True, True, 0)
+        ok_button = Gtk.Button(label="OK")
+        cancel_button = Gtk.Button(label="Cancel")
+        hbox.pack_end(ok_button, False, False, 0)
+        hbox.pack_end(cancel_button, False, False, 0)
+
+        def on_ok_button_clicked(_):
+            self.selected_monitor_index = combobox.get_active()
+            window.close()
+
+        def on_cancel_button_clicked(_):
+            window.close()
+
+        ok_button.connect("clicked", on_ok_button_clicked)
+        cancel_button.connect("clicked", on_cancel_button_clicked)
+
+        image = Gtk.Image()
+        vbox.pack_start(image, True, True, 0)
+
+        def on_combobox_changed(combobox):
+            monitor_index = combobox.get_active()
+            pixbuf = monitor_screenshots[monitor_index]
+            image.set_from_pixbuf(pixbuf)
+
+        combobox.connect("changed", on_combobox_changed)
+        ## Show the first monitor screenshot when opening the dialog.
+        on_combobox_changed(combobox)
+
+        window.show_all()
+        Gtk.main()
+
+    def parameters(self) -> Tuple[int, int, int]:
+        display = Gdk.Display().get_default()
+        self.monitor_dialog()
+        monitor_index = self.selected_monitor_index
+        if monitor_index is None:
+            raise ValueError("Monitor index was not set")
         geometry = display.get_monitor(monitor_index).get_geometry()
         screen = Gdk.Screen().get_default()
         kwargs = {