Added Worker to GUI process for time-consuming tasks (e.g. printing) to make GUI more responsive

photobooth/gui/Qt5Gui/Frames.py

@@ -316,22 +316,22 @@ class CountdownMessage(QtWidgets.QFrame):
 
 class PostprocessMessage(Widgets.TransparentOverlay):
 
-    def __init__(self, parent, tasks, idle_handle, timeout=None,
-                 timeout_handle=None):
+    def __init__(self, parent, tasks, worker, idle_handle,
+                 timeout=None, timeout_handle=None):
 
         if timeout_handle is None:
             timeout_handle = idle_handle
 
         super().__init__(parent, timeout, timeout_handle)
         self.setObjectName('PostprocessMessage')
-        self.initFrame(tasks, idle_handle)
+        self.initFrame(tasks, idle_handle, worker)
 
-    def initFrame(self, tasks, idle_handle):
+    def initFrame(self, tasks, idle_handle, worker):
 
         def disableAndCall(button, handle):
             button.setEnabled(False)
             button.update()
-            handle()
+            worker.put(handle)
 
         def createButton(task):
             button = QtWidgets.QPushButton(task.label)

photobooth/gui/Qt5Gui/PyQt5Gui.py

@@ -36,6 +36,7 @@ from ..GuiPostprocessor import GuiPostprocessor
 from . import styles
 from . import Frames
 from . import Receiver
+from . import Worker
 
 
 class PyQt5Gui(GuiSkeleton):
@@ -49,6 +50,7 @@ class PyQt5Gui(GuiSkeleton):
         is_start, unparsed_args = self._parseArgs()
         self._initUI(argv[:1] + unparsed_args)
         self._initReceiver()
+        self._initWorker()
 
         self._picture = None
         self._postprocess = GuiPostprocessor(self._cfg)
@@ -101,6 +103,12 @@ class PyQt5Gui(GuiSkeleton):
         self._receiver.notify.connect(self.handleState)
         self._receiver.start()
 
+    def _initWorker(self):
+
+        # Create worker thread for time consuming tasks to keep gui responsive
+        self._worker = Worker.Worker(self._comm)
+        self._worker.start()
+
     def _enableEscape(self):
 
         self._is_escape = True
@@ -131,6 +139,7 @@ class PyQt5Gui(GuiSkeleton):
         if state.target == TeardownEvent.WELCOME:
             self._comm.send(Workers.MASTER, GuiEvent('welcome'))
         elif state.target in (TeardownEvent.EXIT, TeardownEvent.RESTART):
+            self._worker.put(None)
             self._app.exit(0)
 
     def showError(self, state):
@@ -229,7 +238,7 @@ class PyQt5Gui(GuiSkeleton):
         postproc_t = self._cfg.getInt('Photobooth', 'postprocess_time')
 
         Frames.PostprocessMessage(
-            self._gui.centralWidget(), tasks,
+            self._gui.centralWidget(), tasks, self._worker,
             lambda: self._comm.send(Workers.MASTER, GuiEvent('idle')),
             postproc_t * 1000)
 

photobooth/gui/Qt5Gui/Worker.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+# Photobooth - a flexible photo booth software
+# Copyright (C) 2018  Balthasar Reuter <photobooth at re - web dot eu>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+import queue
+
+from PyQt5 import QtCore
+
+
+class Worker(QtCore.QThread):
+
+    def __init__(self, comm):
+
+        super().__init__()
+        self._comm = comm
+        self._queue = queue.Queue()
+
+    def put(self, task):
+
+        self._queue.put(task)
+
+    def get(self):
+
+        return self._queue.get()
+
+    def done(self):
+
+        self._queue.task_done()
+
+    def run(self):
+
+        while True:
+            task = self.get()
+            if task is None:
+                break
+            task()
+            self.done()