LibWeb: Add stroke-linecap attribute and plumb it to SVGGraphicsElement

SVGGraphicsElement then goes ahead and does nothing with it for now.

Userland/Libraries/LibWeb/CSS/ComputedValues.h

@@ -144,6 +144,7 @@ public:
     static float fill_opacity() { return 1.0f; }
     static CSS::FillRule fill_rule() { return CSS::FillRule::Nonzero; }
     static CSS::ClipRule clip_rule() { return CSS::ClipRule::Nonzero; }
+    static CSS::StrokeLinecap stroke_linecap() { return CSS::StrokeLinecap::Butt; }
     static float stroke_opacity() { return 1.0f; }
     static float stop_opacity() { return 1.0f; }
     static CSS::TextAnchor text_anchor() { return CSS::TextAnchor::Start; }
@@ -464,6 +465,7 @@ public:
     CSS::FillRule fill_rule() const { return m_inherited.fill_rule; }
     Optional<SVGPaint> const& stroke() const { return m_inherited.stroke; }
     float fill_opacity() const { return m_inherited.fill_opacity; }
+    CSS::StrokeLinecap stroke_linecap() const { return m_inherited.stroke_linecap; }
     float stroke_opacity() const { return m_inherited.stroke_opacity; }
     LengthPercentage const& stroke_width() const { return m_inherited.stroke_width; }
     Color stop_color() const { return m_noninherited.stop_color; }
@@ -555,6 +557,7 @@ protected:
         CSS::FillRule fill_rule { InitialValues::fill_rule() };
         Optional<SVGPaint> stroke;
         float fill_opacity { InitialValues::fill_opacity() };
+        CSS::StrokeLinecap stroke_linecap { InitialValues::stroke_linecap() };
         float stroke_opacity { InitialValues::stroke_opacity() };
         LengthPercentage stroke_width { Length::make_px(1) };
         CSS::TextAnchor text_anchor { InitialValues::text_anchor() };
@@ -791,6 +794,7 @@ public:
     void set_stroke(SVGPaint value) { m_inherited.stroke = value; }
     void set_fill_rule(CSS::FillRule value) { m_inherited.fill_rule = value; }
     void set_fill_opacity(float value) { m_inherited.fill_opacity = value; }
+    void set_stroke_linecap(CSS::StrokeLinecap value) { m_inherited.stroke_linecap = value; }
     void set_stroke_opacity(float value) { m_inherited.stroke_opacity = value; }
     void set_stroke_width(LengthPercentage value) { m_inherited.stroke_width = value; }
     void set_stop_color(Color value) { m_noninherited.stop_color = value; }

Userland/Libraries/LibWeb/CSS/Enums.json

@@ -417,6 +417,11 @@
     "thin",
     "none"
   ],
+  "stroke-linecap": [
+    "butt",
+    "square",
+    "round"
+  ],
   "text-align": [
     "center",
     "justify",

Userland/Libraries/LibWeb/CSS/Keywords.json

@@ -90,6 +90,7 @@
   "bottom",
   "break-word",
   "browser",
+  "butt",
   "button",
   "buttonborder",
   "buttonface",

Userland/Libraries/LibWeb/CSS/Properties.json

@@ -2418,6 +2418,15 @@
       "paint"
     ]
   },
+  "stroke-linecap": {
+    "affects-layout": false,
+    "animation-type": "discrete",
+    "inherited": true,
+    "initial": "butt",
+    "valid-types": [
+      "stroke-linecap"
+    ]
+  },
   "stroke-opacity": {
     "affects-layout": false,
     "animation-type": "by-computed-value",

Userland/Libraries/LibWeb/CSS/StyleProperties.cpp

@@ -326,6 +326,12 @@ float StyleProperties::fill_opacity() const
     return resolve_opacity_value(*value);
 }
 
+Optional<CSS::StrokeLinecap> StyleProperties::stroke_linecap() const
+{
+    auto value = property(CSS::PropertyID::StrokeLinecap);
+    return keyword_to_stroke_linecap(value->to_keyword());
+}
+
 float StyleProperties::stroke_opacity() const
 {
     auto value = property(CSS::PropertyID::StrokeOpacity);

Userland/Libraries/LibWeb/CSS/StyleProperties.h

@@ -177,6 +177,7 @@ public:
     Color stop_color() const;
     float stop_opacity() const;
     float fill_opacity() const;
+    Optional<CSS::StrokeLinecap> stroke_linecap() const;
     float stroke_opacity() const;
     Optional<CSS::FillRule> fill_rule() const;
     Optional<CSS::ClipRule> clip_rule() const;