Merge branch 'pdf-preview' into 'master'

#35 pdf preview

See merge request !16

Dockerfile

@@ -41,3 +41,11 @@ ENV LC_ALL en_US.UTF-8
 # From https://it.i88.ca/2016/03/how-to-fix-importerror-libgssapikrb5so2.html
 # python3.7 -m unittest fails without this
 RUN apt-get -y install libgssapi-krb5-2
+
+# Necessary for import of PySide2.QtWebEngineWidgets to work
+RUN apt-get -y install libnss3 \
+                       libxcomposite-dev \
+                       libxcursor-dev \
+                       libxi-dev \
+                       libxtst-dev \
+                       libxrandr-dev

soitool/main_window.py

@@ -6,11 +6,12 @@ out to separate modules.
 """
 import sys
 import os
-from PySide2.QtCore import QRectF, QPoint, QTimer, Qt
+from PySide2.QtCore import QRectF, QPoint, QTimer, Qt, QUrl
 from PySide2.QtWidgets import QTabWidget, QWidget, QMainWindow, \
     QApplication, QHBoxLayout, QVBoxLayout, QPushButton, QLabel, \
     QAbstractItemView, QListWidget, QListWidgetItem, QAction, QGraphicsScene, \
     QGraphicsView, QScrollArea, QGraphicsRectItem
+from PySide2.QtWebEngineWidgets import QWebEngineView, QWebEngineSettings
 from PySide2.QtGui import QBrush, QIcon, QPalette, QFont, QPixmap
 from soitool.modules.module_table import TableModule
 
@@ -481,6 +482,36 @@ class InlineEditableSOIView(QScrollArea):
         self.view.translate(delta.x(), delta.y())
 
 
+# pylint: disable=r0903
+class PDFPreviewWidget(QWebEngineView):
+    """Widget to preview PDFs using QWebEngineView with PDF plugin.
+
+    Inspired by the following sources:
+    * https://doc.qt.io/qt-5/qtwebengine-features.html#pdf-file-viewing
+    * https://doc.qt.io/qt-5/qtwebengine-webenginewidgets-simplebrowser-example.html
+
+    The load method interited from QWebEngineView's can be used to load a new
+    URL, and the inherited reload method can be used to reload the currently
+    opened URL.
+
+    Parameters
+    ----------
+    initial_url : QUrl
+        URL to load by default. Used for QWebEngineView's .load method
+        https://doc.qt.io/qtforpython/PySide2/QtWebEngineWidgets/QWebEngineView.html#detailed-description
+    """
+
+    def __init__(self, initial_url):
+        super().__init__()
+        self.page().settings().setAttribute(QWebEngineSettings.PluginsEnabled,
+                                            True)
+        # the following setting is the default, but explicitly enabling to be
+        # explicit
+        self.page().settings().setAttribute(QWebEngineSettings.
+                                            PdfViewerEnabled, True)
+        self.load(QUrl(initial_url))
+
+
 if __name__ == "__main__":
     app = QApplication(sys.argv)
     WINDOW = MainWindow()