rework the dirtying of the stylesheet

Include/RmlUi/Core/ElementDocument.h

@@ -178,9 +178,6 @@ class RMLUICORE_API ElementDocument : public Element
 	// The original path this document came from
 	String source_url;
 
-	// The document's style sheet.
-	StyleSheet* style_sheet;
-
 	// The document's style sheet container.
 	SharedPtr<StyleSheetContainer> style_sheet_container;
 

Include/RmlUi/Core/StyleSheetContainer.h

@@ -54,14 +54,11 @@ class RMLUICORE_API StyleSheetContainer : public NonCopyMoveable
 	/// Loads a style from a CSS definition.
 	bool LoadStyleSheetContainer(Stream* stream, int begin_line_number = 1);
 
-	/// Combines the underlying media blocks into a final merged stylesheet according to the given media features
+	/// Returns the currently compiled style sheet that has been merged from incorporating all matching media blocks
+	/// or creates it ad-hoc if the given properties differ from the currently stored values.
 	/// @param[in] dimensions The current context viewport dimensions
 	/// @param[in] density_ratio The current context ratio of 'dp' units to 'px' units
-	/// @return True if a new style sheet has been compiled
-	bool UpdateMediaFeatures(Vector2i dimensions, float density_ratio);
-
-	/// Returns the currently compiled style sheet that has been merged from incorporating all matching media blocks.
-	StyleSheet* GetCompiledStyleSheet() const;
+	StyleSheet* GetCompiledStyleSheet(Vector2i dimensions, float density_ratio);
 
 	/// Combines this style sheet container with another one, producing a new sheet container.
 	SharedPtr<StyleSheetContainer> CombineStyleSheetContainer(const StyleSheetContainer& container) const;

Source/Core/Context.cpp

@@ -39,6 +39,7 @@
 #include "../../Include/RmlUi/Core/SystemInterface.h"
 #include "../../Include/RmlUi/Core/StreamMemory.h"
 #include "DataModel.h"
+#include "ElementStyle.h"
 #include "EventDispatcher.h"
 #include "PluginRegistry.h"
 #include "StreamFile.h"
@@ -125,6 +126,9 @@ void Context::SetDimensions(const Vector2i _dimensions)
 			ElementDocument* document = root->GetChild(i)->GetOwnerDocument();
 			if (document != nullptr)
 			{
+				// Invalidate definition to force stylesheet recompilation
+				document->GetStyle()->DirtyDefinition();
+
 				document->DirtyVwAndVhProperties();
 				document->DirtyLayout();
 				document->DirtyPosition();
@@ -153,6 +157,9 @@ void Context::SetDensityIndependentPixelRatio(float _density_independent_pixel_r
 			ElementDocument* document = root->GetChild(i)->GetOwnerDocument();
 			if (document != nullptr)
 			{
+				// Invalidate definition to force stylesheet recompilation
+				document->GetStyle()->DirtyDefinition();
+
 				document->DirtyDpProperties();
 			}
 		}

Source/Core/ElementDocument.cpp

@@ -48,7 +48,6 @@ namespace Rml {
 
 ElementDocument::ElementDocument(const String& tag) : Element(tag)
 {
-	style_sheet = nullptr;
 	context = nullptr;
 
 	modal = false;
@@ -140,10 +139,7 @@ void ElementDocument::ProcessHeader(const DocumentHeader* document_header)
 
 	// If a style sheet is available, set it on the document and release it.
 	if (new_style_sheet)
-	{
 		SetStyleSheetContainer(std::move(new_style_sheet));
-		style_sheet = style_sheet_container->GetCompiledStyleSheet();
-	}
 
 	// Load scripts.
 	for (const DocumentHeader::Resource& script : header.scripts)
@@ -200,17 +196,14 @@ void ElementDocument::SetStyleSheetContainer(SharedPtr<StyleSheetContainer> _sty
 
 	style_sheet_container = std::move(_style_sheet_container);
 
-	if (style_sheet_container && context)
-		style_sheet_container->UpdateMediaFeatures(context->GetDimensions(), context->GetDensityIndependentPixelRatio());
-
 	GetStyle()->DirtyDefinition();
 }
 
 // Returns the document's style sheet.
 const StyleSheet* ElementDocument::GetStyleSheet() const
 {
-	if(style_sheet_container)
-		return style_sheet_container->GetCompiledStyleSheet();
+	if(context && style_sheet_container)
+		return style_sheet_container->GetCompiledStyleSheet(context->GetDimensions(), context->GetDensityIndependentPixelRatio());
 	return nullptr;
 }
 
@@ -405,10 +398,7 @@ void ElementDocument::LoadExternalScript(const String& RMLUI_UNUSED_PARAMETER(so
 
 // Updates the document, including its layout
 void ElementDocument::UpdateDocument()
-{	
-	if (context && style_sheet_container && style_sheet_container->UpdateMediaFeatures(context->GetDimensions(), context->GetDensityIndependentPixelRatio()))
-		GetStyle()->DirtyDefinition();
-
+{
 	const float dp_ratio = (context ? context->GetDensityIndependentPixelRatio() : 1.0f);
 	const Vector2f vp_dimensions = (context ? Vector2f(context->GetDimensions()) : Vector2f(1.0f));
 	Update(dp_ratio, vp_dimensions);

Source/Core/StyleSheetContainer.cpp

@@ -49,10 +49,10 @@ bool StyleSheetContainer::LoadStyleSheetContainer(Stream* stream, int begin_line
 	return rule_count >= 0;
 }
 
-bool StyleSheetContainer::UpdateMediaFeatures(Vector2i dimensions, float density_ratio)
+StyleSheet* StyleSheetContainer::GetCompiledStyleSheet(Vector2i dimensions, float density_ratio)
 {
     if(compiled_style_sheet && dimensions == current_dimensions && density_ratio == current_density_ratio)
-        return false;
+        return compiled_style_sheet.get();
 
     UniquePtr<StyleSheet> new_sheet = MakeUnique<StyleSheet>();
 
@@ -136,13 +136,7 @@ bool StyleSheetContainer::UpdateMediaFeatures(Vector2i dimensions, float density
 
     compiled_style_sheet = std::move(new_sheet);
     current_dimensions = dimensions;
-    current_density_ratio = current_density_ratio;
-
-    return true;
-}
-
-StyleSheet* StyleSheetContainer::GetCompiledStyleSheet() const
-{
+    current_density_ratio = density_ratio;
     return compiled_style_sheet.get();
 }
 

Tests/Source/UnitTests/MediaQueries.cpp

@@ -213,7 +213,8 @@ TEST_CASE("mediaqueries.dynamic")
 	CHECK(elems[0]->GetBox() == Box(Vector2f(32.0f, 32.0f)));
 
 	context->SetDimensions(Vector2i(480, 320));
-	document->UpdateDocument();
+
+	context->Update();
 
 	CHECK(elems[0]->GetBox() == Box(Vector2f(64.0f, 64.0f)));