add option to export background grid to pdf

resources/etc/OpenBoard.config

@@ -128,6 +128,7 @@ Margin=20
 PageFormat=A4
 Resolution=300
 ZoomBehavior=4
+ExportBackgroundGrid=false
 
 [Podcast]
 AudioRecordingDevice=Default

src/adaptors/UBExportPDF.cpp

@@ -106,7 +106,15 @@ bool UBExportPDF::persistsDocument(UBDocumentProxy* pDocumentProxy, const QStrin
         // set background to white, no crossing for PDF output
         bool isDark = scene->isDarkBackground();
         UBPageBackground pageBackground = scene->pageBackground();
-        scene->setBackground(false, UBPageBackground::plain);
+
+        if (UBSettings::settings()->exportBackgroundGrid->get().toBool())
+        {
+            scene->setBackground(false, pageBackground);
+        }
+        else
+        {
+            scene->setBackground(false, UBPageBackground::plain);
+        }
 
         // pageSize is the output PDF page size; it is set to equal the scene's boundary size; if the contents
         // of the scene overflow from the boundaries, they will be scaled down.

src/core/UBSettings.cpp

@@ -409,6 +409,7 @@ void UBSettings::init()
 
     pdfZoomBehavior = new UBSetting(this, "PDF", "ZoomBehavior", "4");
     enableQualityLossToIncreaseZoomPerfs = new UBSetting(this, "PDF", "enableQualityLossToIncreaseZoomPerfs", true);
+    exportBackgroundGrid = new UBSetting(this, "PDF", "ExportBackgroundGrid", false);
 
     podcastFramesPerSecond = new UBSetting(this, "Podcast", "FramesPerSecond", 10);
     podcastVideoSize = new UBSetting(this, "Podcast", "VideoSize", "Medium");

src/core/UBSettings.h

@@ -361,6 +361,7 @@ class UBSettings : public QObject
 
         UBSetting* pdfZoomBehavior;
         UBSetting* enableQualityLossToIncreaseZoomPerfs;
+        UBSetting* exportBackgroundGrid;
 
         UBSetting* podcastFramesPerSecond;
         UBSetting* podcastVideoSize;