I173 print help doc in pdf

closes #173 (closed)

Note: the images in help document must be less than 11in/1584px in width to fit in the saved pdf document.

sohstationviewer/view/help_view.py

 import sys
 from pathlib import Path
 from typing import Tuple, Callable, Union, List, Dict, Optional
+from PIL import Image
 
 from PySide6 import QtCore, QtGui, QtWidgets
 from PySide6.QtPrintSupport import QPrinter
@@ -108,7 +109,11 @@ class HelpBrowser(QtWidgets.QWidget):
         """
         self.search_results_path: Path = self.docdir_path.joinpath(
             'Search Results.md')
-
+        """
+        default_pdf_file_name: the default name for pdf file when the current
+        help document is saved
+        """
+        self.default_pdf_file_name: str = ''
         # Get screen dimensions
         geom = QtGui.QGuiApplication.screens()[0].availableGeometry()
         self.setGeometry(10, 10,
@@ -133,9 +138,9 @@ class HelpBrowser(QtWidgets.QWidget):
         self.go_to_search_results_button: Optional[QtWidgets.QToolButton] = \
             None
         """
-        print_button: button to print the current document
+        save_button: button to save the current document to a pdf file
         """
-        self.print_button: Optional[QtWidgets.QToolButton] = None
+        self.save_button: Optional[QtWidgets.QToolButton] = None
         """
         tree_view: tree list of all documents
         """
@@ -293,7 +298,7 @@ class HelpBrowser(QtWidgets.QWidget):
             'Navigate to Search Results', self.go_search_results)
         self.go_to_search_results_button.setEnabled(False)
 
-        self.print_button = self.add_nav_button(
+        self.save_button = self.add_nav_button(
             nav_bar,
             self.style().standardIcon(
                 QStyle.StandardPixmap.SP_DialogSaveButton),
@@ -373,10 +378,46 @@ class HelpBrowser(QtWidgets.QWidget):
         Load file from file_path to help_view
 
         :param file_path:  absolute path to a document
-        :type file_path: str
         """
         url = QtCore.QUrl.fromLocalFile(file_path)
         self.help_view.setSource(url)
+        self._check_image_size(file_path)
+        self._set_default_pdf_file_name(file_path)
+
+    def _set_default_pdf_file_name(self, file_path: str) -> str:
+        """
+        Set the default_pdf_file_name for the current help document
+
+        :param file_path:  absolute path to a document
+        """
+        file_name = file_path.split(' _ ')[1]
+        file_name = "SOHViewer Help - " + file_name
+        self.default_pdf_file_name = file_name.replace('.help.md', '')
+        print("default:", self.default_pdf_file_name)
+
+    def _check_image_size(self, file_path: str) -> None:
+        """
+        Checking all image in the given file to give a warning if there is any
+        image of which width is greater than 1584px which is the limit of being
+        cut off when saving the file to pdf
+
+        :param file_path: path to the help document
+        """
+        with open(file_path) as f:
+            lines = f.readlines()
+            for line in lines:
+                s = line.split('src="')
+                if len(s) == 2:
+                    img_path = s[1].split('"')[0]
+                    abs_img_path = self.docdir_path.joinpath(img_path)
+                    img = Image.open(abs_img_path)
+                    if img.width > 1584:
+                        msg = (f"Image {abs_img_path}'s\n\nwidth is "
+                               f"{img.width}px which is GREATER than 1584px,"
+                               "\n\nwhich results in some cut off of the "
+                               "image when saving this help document to file.")
+                        QtWidgets.QMessageBox.warning(
+                            self, 'Oversize image', msg)
 
     @QtCore.Slot()
     def on_tree_view_item_clicked(self, index: QtCore.QModelIndex):
@@ -541,15 +582,22 @@ class HelpBrowser(QtWidgets.QWidget):
     def save_to_pdf(self):
         """
         Save the current document to pdf file.
+
+        A3 size is selected because the current font look well in that. After
+        the document is saved, user can print it in the size they want. The
+        size of A3 is 11.7 x 16.5. So the width of pictures in the document
+        will be cut off if greater than (11.7 - margins).
+
         Note: the pictures' width in the document must be smaller than 11 in/
             1584px or its content will be cut off.
         """
         home_path = Path.home()
         doc_path = home_path.joinpath("Documents")
-        save_file = QtWidgets.QFileDialog.getSaveFileName(self, 'Save to PDF',
-                                                          doc_path.as_posix())
-        if save_file:
-            filename = save_file[0]
+        file_path = doc_path.joinpath(self.default_pdf_file_name)
+        save_file = QtWidgets.QFileDialog.getSaveFileName(
+            self, 'Save to PDF', file_path.as_posix())[0]
+        if save_file != "":
+            filename = save_file
             if not filename.endswith('.pdf'):
                 filename = filename + '.pdf'
             printer = QPrinter(
@@ -560,6 +608,8 @@ class HelpBrowser(QtWidgets.QWidget):
             printer.setOutputFormat(QPrinter.OutputFormat.PdfFormat)
             printer.setOutputFileName(filename)
             self.help_view.document().print_(printer)
+            msg = f"The current help document has been saved at {filename}"
+            QtWidgets.QMessageBox.information(self, "Document Saved", msg)
 
 
 def main():