Filter graph: Explicitly switch between canvas and ImGui managed DPI for context menus. Fixes #932 for real.

Author: azonenberg

lib

@@ -434,9 +434,7 @@ bool FilterGraphEditor::DoRender()
 
 	// NodeEditor seems to handle DPI scaling on its own
 	// so turn off global scaling to avoid double scaling
-	ImGui::GetStyle().FontScaleDpi = 1.0f;
-	ImGui::UpdateCurrentFontSize(0.0f);
-	m_parent->ResetStyle();
+	SetCanvasManagedDPI();
 
 	//Handle dropping a stream or channel from the browser
 	ax::NodeEditor::NodeId newNode;
@@ -619,10 +617,8 @@ bool FilterGraphEditor::DoRender()
 	bool triggerChanged = HandleNodeProperties();
 	HandleBackgroundContextMenu();
 
-	ImGui::GetStyle().FontScaleDpi = ImGui::GetWindowViewport()->DpiScale;
-	ImGui::UpdateCurrentFontSize(0.0f);
-	m_parent->ResetStyle();
-
+	//Done with canvas stuff
+	SetImGuiManagedDPI();
 	ax::NodeEditor::End();
 
 	//Refresh all of our groups to have up-to-date child contents
@@ -954,7 +950,9 @@ void FilterGraphEditor::DoNodeForGroupOutputs(shared_ptr<FilterGraphGroup> group
 	{
 		//Output port
 		ax::NodeEditor::Suspend();
+			SetImGuiManagedDPI();
 			OutputPortTooltip(hoveredStream);
+			SetCanvasManagedDPI();
 		ax::NodeEditor::Resume();
 	}
 
@@ -1553,6 +1551,7 @@ void FilterGraphEditor::HandleLinkCreationRequests(Filter*& fReconfigure)
 	ax::NodeEditor::EndCreate();
 
 	ax::NodeEditor::Suspend();
+	SetImGuiManagedDPI();
 
 		//Create-filter menu
 		if(ImGui::BeginPopup("Create Filter"))
@@ -1568,9 +1567,30 @@ void FilterGraphEditor::HandleLinkCreationRequests(Filter*& fReconfigure)
 			ImGui::EndPopup();
 		}
 
+	SetCanvasManagedDPI();
 	ax::NodeEditor::Resume();
 }
 
+/**
+	@brief Use 1.0 as the DPI since the canvas scales independently
+ */
+void FilterGraphEditor::SetCanvasManagedDPI()
+{
+	ImGui::GetStyle().FontScaleDpi = 1.0f;
+	ImGui::UpdateCurrentFontSize(0.0f);
+	m_parent->ResetStyle();
+}
+
+/**
+	@brief Use the ImGui viewport scale as the DPI scale
+ */
+void FilterGraphEditor::SetImGuiManagedDPI()
+{
+	ImGui::GetStyle().FontScaleDpi = ImGui::GetWindowViewport()->DpiScale;
+	ImGui::UpdateCurrentFontSize(0.0f);
+	m_parent->ResetStyle();
+}
+
 /**
 	@brief Determine if a proposed edge in the filter graph is a back edge (one whose creation would lead to a cycle)
 
@@ -1742,11 +1762,8 @@ void FilterGraphEditor::FilterMenu(StreamDescriptor stream)
 void FilterGraphEditor::FilterSubmenu(StreamDescriptor stream, const string& name, Filter::Category cat)
 {
 	auto& refs = m_parent->GetSession().GetReferenceFilters();
-
 	if(ImGui::BeginMenu(name.c_str()))
 	{
-		ImGui::PushFont(nullptr, 0);
-
 		//Find all filters in this category and sort them alphabetically
 		vector<string> sortedNames;
 		for(auto it : refs)
@@ -1786,8 +1803,6 @@ void FilterGraphEditor::FilterSubmenu(StreamDescriptor stream, const string& nam
 				ax::NodeEditor::SetNodePosition(GetID(f), mousePos);
 			}
 		}
-
-		ImGui::PopFont();
 		ImGui::EndMenu();
 	}
 }

src/ngscopeclient/FilterGraphEditor.cpp

@@ -208,6 +208,9 @@ class FilterGraphEditor : public Dialog
 		const std::vector<ImVec2>& positions,
 		std::vector<ImVec2>& forces);
 
+	void SetCanvasManagedDPI();
+	void SetImGuiManagedDPI();
+
 	void ClearOldPropertiesDialogs();
 
 	void NodeIcon(InstrumentChannel* chan, ImVec2 iconpos, ImVec2 iconsize, ImDrawList* list);