ui: improve HTML inline layout and old Reddit rendering

- implement per-side CSS border styles and patterned rendering
  - preserve rectangular rasterization for thin dotted borders
  - separate CSS and native-widget border defaults
  - correct inline atomic-box and vertical-align baseline layout
  - collapse adjacent block margins in rich-text flow
  - preserve forced line breaks and formatting margins
  - size HTML text inputs from font ascent and descent
  - expose replaced-control text baselines to inline layout
  - enforce single-owner painting for inline backgrounds and borders
  - enable and update the old Reddit visual regression golden
  - add generic layout, border, and form-control regression tests
  - document spec-first HTML work and project build conventions

include/eepp/graphics/richtext.hpp

@@ -191,10 +191,11 @@ class EE_API RichText : public Drawable {
 						InlineClear clearType = InlineClear::None, Float baseline = -1.f,
 						const BaselineAlignValue& baselineAlign = {}, InlineSource source = {},
 						bool isBlock = false, bool isBlockFormattingContext = false,
-						std::shared_ptr<const std::vector<FloatExclusion>> propagatedFloats = {} );
+						std::shared_ptr<const std::vector<FloatExclusion>> propagatedFloats = {},
+						const Rectf& margin = Rectf::Zero );
 
 	/** @brief Adds a virtual line break that is not associated with a DOM text character. */
-	void addLineBreak();
+	void addLineBreak( bool forceEmptyLine = false, Float lineHeight = 0.f );
 
 	virtual void draw( const Float& X, const Float& Y, const Vector2f& scale = Vector2f::One,
 					   const Float& rotation = 0, BlendMode effect = BlendMode::Alpha(),
@@ -227,6 +228,7 @@ class EE_API RichText : public Drawable {
 		std::shared_ptr<Drawable> drawable;
 		Rectf margin;
 		Rectf padding;
+		Rectf formattingMargin;
 		Float lineHeight{ 0 };
 		BaselineAlignValue baselineAlign;
 		bool suppressBackground{ false };
@@ -234,6 +236,7 @@ class EE_API RichText : public Drawable {
 		InlineFloat floatType{ InlineFloat::None };
 		InlineClear clearType{ InlineClear::None };
 		bool isLineBreak{ false };
+		bool forceEmptyLine{ false };
 		bool isBlock{ false };
 		bool isBlockFormattingContext{ false };
 		std::shared_ptr<const std::vector<FloatExclusion>> propagatedFloats;
@@ -248,6 +251,7 @@ class EE_API RichText : public Drawable {
 	/** @brief Structure representing a rendered paragraph (line). */
 	struct RenderParagraph {
 		std::vector<RenderSpan> spans;
+		bool forcedEmptyLine{ false };
 		Float y{ 0 };
 		Float height{ 0 };
 		Float maxAscent{ 0 };
@@ -347,10 +351,12 @@ class EE_API RichText : public Drawable {
 			InlineSource source;
 			std::shared_ptr<Drawable> drawable;
 			Sizef size;
+			Rectf formattingMargin;
 			Float baseline{ 0 };
 			InlineFloat floatType{ InlineFloat::None };
 			InlineClear clearType{ InlineClear::None };
 			bool isLineBreak{ false };
+			bool forceEmptyLine{ false };
 			bool isBlock{ false };
 			bool isBlockFormattingContext{ false };
 			std::shared_ptr<const std::vector<FloatExclusion>> propagatedFloats;
@@ -388,6 +394,7 @@ class EE_API RichText : public Drawable {
 		size_t lineIndex{ 0 };
 		Rectf bounds;
 		Rectf paintBounds;
+		Rectf formattingMargin;
 		Int64 startCharIndex{ 0 };
 		Int64 endCharIndex{ 0 };
 		std::shared_ptr<Text> text;

include/eepp/ui/border.hpp

@@ -17,10 +17,13 @@ class UINode;
 
 enum class BorderType : Uint32 { Inside, Outside, Outline };
 
+enum class BorderStyle : Uint32 { None, Hidden, Dotted, Dashed, Solid };
+
 struct EE_API Border {
 	int width = 0;
 	Color color;
 	Color realColor;
+	BorderStyle style{ BorderStyle::Solid };
 };
 
 struct EE_API BorderRadiuses {
@@ -41,6 +44,10 @@ struct EE_API Borders {
 
 	static BorderType toBorderType( const std::string& borderType );
 
+	static std::string fromBorderStyle( BorderStyle borderStyle );
+
+	static BorderStyle toBorderStyle( const std::string& borderStyle );
+
 	static Sizef radiusFromString( const UINode* node, const std::string& val );
 
 	/** Resolves overlapping corner curves with the single proportional scale factor required by

include/eepp/ui/css/propertydefinition.hpp

@@ -207,6 +207,10 @@ enum class PropertyId : Uint32 {
 	BorderRightWidth = String::hash( "border-right-width" ),
 	BorderTopWidth = String::hash( "border-top-width" ),
 	BorderBottomWidth = String::hash( "border-bottom-width" ),
+	BorderLeftStyle = String::hash( "border-left-style" ),
+	BorderRightStyle = String::hash( "border-right-style" ),
+	BorderTopStyle = String::hash( "border-top-style" ),
+	BorderBottomStyle = String::hash( "border-bottom-style" ),
 	BorderTopLeftRadius = String::hash( "border-top-left-radius" ),
 	BorderTopRightRadius = String::hash( "border-top-right-radius" ),
 	BorderBottomLeftRadius = String::hash( "border-bottom-left-radius" ),

include/eepp/ui/uiborderdrawable.hpp

@@ -70,6 +70,14 @@ class EE_API UIBorderDrawable : public Drawable {
 
 	void setBottomWidth( const std::string& bottomWidth );
 
+	void setLeftStyle( const std::string& style );
+
+	void setRightStyle( const std::string& style );
+
+	void setTopStyle( const std::string& style );
+
+	void setBottomStyle( const std::string& style );
+
 	void setTopLeftRadius( const std::string& radius );
 
 	void setTopRightRadius( const std::string& radius );

include/eepp/ui/uihtmlinput.hpp

@@ -29,6 +29,8 @@ class EE_API UIHTMLInput : public UIHTMLWidget {
 
 	virtual void updateLayout();
 
+	Float getReplacedElementBaseline() const;
+
 	const std::string& getInputType() const;
 
 	void setInputType( const std::string& type );
@@ -44,6 +46,7 @@ class EE_API UIHTMLInput : public UIHTMLWidget {
 	String mValue;
 	bool mChecked{ false };
 	bool mSyncingGeometry{ false };
+	bool mHasSpecifiedHeight{ false };
 	bool mHiddenByType{ false };
 	bool mVisibleBeforeHidden{ true };
 	bool mEnabledBeforeHidden{ true };

include/eepp/ui/uihtmltextinput.hpp

@@ -28,6 +28,10 @@ class EE_API UIHTMLTextInput : public UITextInput {
 
 	virtual void onAutoSize();
 
+	Float getIntrinsicContentHeight() const;
+
+	Float getTextBaseline() const;
+
 	Uint32 getHtmlSize() const;
 
 	void setHtmlSize( Uint32 size );

include/eepp/ui/uitextspan.hpp

@@ -165,6 +165,10 @@ class EE_API UITextSpan : public UIRichText {
 
 	virtual void onFontStyleChanged();
 
+	virtual void drawBackground();
+
+	virtual void drawBorder();
+
 	virtual Uint32 onMessage( const NodeMessage* Msg );
 };