LibWeb: Move border painting from Layout::Box to a free function

This will allow us to share some code between inline and non-inline
border painting.

6 files changed, 211 insertions, 128 deletions

diff --git a/Libraries/LibWeb/CMakeLists.txt b/Libraries/LibWeb/CMakeLists.txt
index 35d12d0299..22aae64422 100644
--- a/Libraries/LibWeb/CMakeLists.txt
+++ b/Libraries/LibWeb/CMakeLists.txt
@@ -180,6 +180,7 @@ set(SOURCES
     Page/EventHandler.cpp
     Page/Frame.cpp
     Page/Page.cpp
+    Painting/BorderPainting.cpp
     Painting/StackingContext.cpp
     SVG/SVGElement.cpp
     SVG/SVGGeometryElement.cpp
diff --git a/Libraries/LibWeb/Layout/Box.cpp b/Libraries/LibWeb/Layout/Box.cpp
index 3c0b151da0..a6a7e34b3c 100644
--- a/Libraries/LibWeb/Layout/Box.cpp
+++ b/Libraries/LibWeb/Layout/Box.cpp
@@ -30,125 +30,10 @@
 #include <LibWeb/Layout/BlockBox.h>
 #include <LibWeb/Layout/Box.h>
 #include <LibWeb/Page/Frame.h>
+#include <LibWeb/Painting/BorderPainting.h>
 
 namespace Web::Layout {
 
-void Box::paint_border(PaintContext& context, Edge edge, const Gfx::FloatRect& rect, const BorderData& border_data)
-{
-    float width = border_data.width;
-    if (width <= 0)
-        return;
-
-    auto color = border_data.color;
-    auto border_style = border_data.line_style;
-    int int_width = max((int)width, 1);
-
-    struct Points {
-        Gfx::FloatPoint p1;
-        Gfx::FloatPoint p2;
-    };
-
-    auto points_for_edge = [](Edge edge, const Gfx::FloatRect& rect) -> Points {
-        switch (edge) {
-        case Edge::Top:
-            return { rect.top_left(), rect.top_right() };
-        case Edge::Right:
-            return { rect.top_right(), rect.bottom_right() };
-        case Edge::Bottom:
-            return { rect.bottom_left(), rect.bottom_right() };
-        default: // Edge::Left
-            return { rect.top_left(), rect.bottom_left() };
-        }
-    };
-
-    auto [p1, p2] = points_for_edge(edge, rect);
-
-    if (border_style == CSS::LineStyle::Inset) {
-        auto top_left_color = Color::from_rgb(0x5a5a5a);
-        auto bottom_right_color = Color::from_rgb(0x888888);
-        color = (edge == Edge::Left || edge == Edge::Top) ? top_left_color : bottom_right_color;
-    } else if (border_style == CSS::LineStyle::Outset) {
-        auto top_left_color = Color::from_rgb(0x888888);
-        auto bottom_right_color = Color::from_rgb(0x5a5a5a);
-        color = (edge == Edge::Left || edge == Edge::Top) ? top_left_color : bottom_right_color;
-    }
-
-    auto gfx_line_style = Gfx::Painter::LineStyle::Solid;
-    if (border_style == CSS::LineStyle::Dotted)
-        gfx_line_style = Gfx::Painter::LineStyle::Dotted;
-    if (border_style == CSS::LineStyle::Dashed)
-        gfx_line_style = Gfx::Painter::LineStyle::Dashed;
-
-    if (gfx_line_style != Gfx::Painter::LineStyle::Solid) {
-        switch (edge) {
-        case Edge::Top:
-            p1.move_by(int_width / 2, int_width / 2);
-            p2.move_by(-int_width / 2, int_width / 2);
-            break;
-        case Edge::Right:
-            p1.move_by(-int_width / 2, int_width / 2);
-            p2.move_by(-int_width / 2, -int_width / 2);
-            break;
-        case Edge::Bottom:
-            p1.move_by(int_width / 2, -int_width / 2);
-            p2.move_by(-int_width / 2, -int_width / 2);
-            break;
-        case Edge::Left:
-            p1.move_by(int_width / 2, int_width / 2);
-            p2.move_by(int_width / 2, -int_width / 2);
-            break;
-        }
-        context.painter().draw_line({ (int)p1.x(), (int)p1.y() }, { (int)p2.x(), (int)p2.y() }, color, int_width, gfx_line_style);
-        return;
-    }
-
-    auto draw_line = [&](auto& p1, auto& p2) {
-        context.painter().draw_line({ (int)p1.x(), (int)p1.y() }, { (int)p2.x(), (int)p2.y() }, color, 1, gfx_line_style);
-    };
-
-    float p1_step = 0;
-    float p2_step = 0;
-
-    switch (edge) {
-    case Edge::Top:
-        p1_step = style().border_left().width / (float)int_width;
-        p2_step = style().border_right().width / (float)int_width;
-        for (int i = 0; i < int_width; ++i) {
-            draw_line(p1, p2);
-            p1.move_by(p1_step, 1);
-            p2.move_by(-p2_step, 1);
-        }
-        break;
-    case Edge::Right:
-        p1_step = style().border_top().width / (float)int_width;
-        p2_step = style().border_bottom().width / (float)int_width;
-        for (int i = int_width - 1; i >= 0; --i) {
-            draw_line(p1, p2);
-            p1.move_by(-1, p1_step);
-            p2.move_by(-1, -p2_step);
-        }
-        break;
-    case Edge::Bottom:
-        p1_step = style().border_left().width / (float)int_width;
-        p2_step = style().border_right().width / (float)int_width;
-        for (int i = int_width - 1; i >= 0; --i) {
-            draw_line(p1, p2);
-            p1.move_by(p1_step, -1);
-            p2.move_by(-p2_step, -1);
-        }
-        break;
-    case Edge::Left:
-        p1_step = style().border_top().width / (float)int_width;
-        p2_step = style().border_bottom().width / (float)int_width;
-        for (int i = 0; i < int_width; ++i) {
-            draw_line(p1, p2);
-            p1.move_by(1, p1_step);
-            p2.move_by(1, -p2_step);
-        }
-        break;
-    }
-}
-
 void Box::paint(PaintContext& context, PaintPhase phase)
 {
     if (!is_visible())
@@ -187,10 +72,10 @@ void Box::paint(PaintContext& context, PaintPhase phase)
         bordered_rect.set_y(padded_rect.y() - box_model().border.top.to_px(*this));
         bordered_rect.set_height(padded_rect.height() + box_model().border.top.to_px(*this) + box_model().border.bottom.to_px(*this));
 
-        paint_border(context, Edge::Left, bordered_rect, style().border_left());
-        paint_border(context, Edge::Right, bordered_rect, style().border_right());
-        paint_border(context, Edge::Top, bordered_rect, style().border_top());
-        paint_border(context, Edge::Bottom, bordered_rect, style().border_bottom());
+        Painting::paint_border(context, Painting::BorderEdge::Left, bordered_rect, style());
+        Painting::paint_border(context, Painting::BorderEdge::Right, bordered_rect, style());
+        Painting::paint_border(context, Painting::BorderEdge::Top, bordered_rect, style());
+        Painting::paint_border(context, Painting::BorderEdge::Bottom, bordered_rect, style());
     }
 
     Layout::NodeWithStyleAndBoxModelMetrics::paint(context, phase);
diff --git a/Libraries/LibWeb/Layout/Box.h b/Libraries/LibWeb/Layout/Box.h
index 0fa084ec7b..c08460f6c6 100644
--- a/Libraries/LibWeb/Layout/Box.h
+++ b/Libraries/LibWeb/Layout/Box.h
@@ -92,14 +92,6 @@ protected:
 private:
     virtual bool is_box() const final { return true; }
 
-    enum class Edge {
-        Top,
-        Right,
-        Bottom,
-        Left,
-    };
-    void paint_border(PaintContext&, Edge, const Gfx::FloatRect&, const BorderData&);
-
     Gfx::FloatPoint m_offset;
     Gfx::FloatSize m_size;
 
diff --git a/Libraries/LibWeb/Layout/LineBoxFragment.cpp b/Libraries/LibWeb/Layout/LineBoxFragment.cpp
index af24ce2c38..e6a6cfeeda 100644
--- a/Libraries/LibWeb/Layout/LineBoxFragment.cpp
+++ b/Libraries/LibWeb/Layout/LineBoxFragment.cpp
@@ -29,6 +29,7 @@
 #include <LibWeb/Layout/InitialContainingBlockBox.h>
 #include <LibWeb/Layout/LineBoxFragment.h>
 #include <LibWeb/Layout/TextNode.h>
+#include <LibWeb/Painting/BorderPainting.h>
 #include <LibWeb/Painting/PaintContext.h>
 #include <ctype.h>
 
diff --git a/Libraries/LibWeb/Painting/BorderPainting.cpp b/Libraries/LibWeb/Painting/BorderPainting.cpp
new file mode 100644
index 0000000000..d3721245e2
--- /dev/null
+++ b/Libraries/LibWeb/Painting/BorderPainting.cpp
@@ -0,0 +1,162 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibGfx/Painter.h>
+#include <LibWeb/Painting/BorderPainting.h>
+#include <LibWeb/Painting/PaintContext.h>
+
+namespace Web::Painting {
+
+void paint_border(PaintContext& context, BorderEdge edge, const Gfx::FloatRect& rect, const LayoutStyle& style)
+{
+    const auto& border_data = [&] {
+        switch (edge) {
+        case BorderEdge::Top:
+            return style.border_top();
+        case BorderEdge::Right:
+            return style.border_right();
+        case BorderEdge::Bottom:
+            return style.border_bottom();
+        default: // BorderEdge::Left:
+            return style.border_left();
+        }
+    }();
+
+    float width = border_data.width;
+    if (width <= 0)
+        return;
+
+    auto color = border_data.color;
+    auto border_style = border_data.line_style;
+    int int_width = max((int)width, 1);
+
+    struct Points {
+        Gfx::FloatPoint p1;
+        Gfx::FloatPoint p2;
+    };
+
+    auto points_for_edge = [](BorderEdge edge, const Gfx::FloatRect& rect) -> Points {
+        switch (edge) {
+        case BorderEdge::Top:
+            return { rect.top_left(), rect.top_right() };
+        case BorderEdge::Right:
+            return { rect.top_right(), rect.bottom_right() };
+        case BorderEdge::Bottom:
+            return { rect.bottom_left(), rect.bottom_right() };
+        default: // Edge::Left
+            return { rect.top_left(), rect.bottom_left() };
+        }
+    };
+
+    auto [p1, p2] = points_for_edge(edge, rect);
+
+    if (border_style == CSS::LineStyle::Inset) {
+        auto top_left_color = Color::from_rgb(0x5a5a5a);
+        auto bottom_right_color = Color::from_rgb(0x888888);
+        color = (edge == BorderEdge::Left || edge == BorderEdge::Top) ? top_left_color : bottom_right_color;
+    } else if (border_style == CSS::LineStyle::Outset) {
+        auto top_left_color = Color::from_rgb(0x888888);
+        auto bottom_right_color = Color::from_rgb(0x5a5a5a);
+        color = (edge == BorderEdge::Left || edge == BorderEdge::Top) ? top_left_color : bottom_right_color;
+    }
+
+    auto gfx_line_style = Gfx::Painter::LineStyle::Solid;
+    if (border_style == CSS::LineStyle::Dotted)
+        gfx_line_style = Gfx::Painter::LineStyle::Dotted;
+    if (border_style == CSS::LineStyle::Dashed)
+        gfx_line_style = Gfx::Painter::LineStyle::Dashed;
+
+    if (gfx_line_style != Gfx::Painter::LineStyle::Solid) {
+        switch (edge) {
+        case BorderEdge::Top:
+            p1.move_by(int_width / 2, int_width / 2);
+            p2.move_by(-int_width / 2, int_width / 2);
+            break;
+        case BorderEdge::Right:
+            p1.move_by(-int_width / 2, int_width / 2);
+            p2.move_by(-int_width / 2, -int_width / 2);
+            break;
+        case BorderEdge::Bottom:
+            p1.move_by(int_width / 2, -int_width / 2);
+            p2.move_by(-int_width / 2, -int_width / 2);
+            break;
+        case BorderEdge::Left:
+            p1.move_by(int_width / 2, int_width / 2);
+            p2.move_by(int_width / 2, -int_width / 2);
+            break;
+        }
+        context.painter().draw_line({ (int)p1.x(), (int)p1.y() }, { (int)p2.x(), (int)p2.y() }, color, int_width, gfx_line_style);
+        return;
+    }
+
+    auto draw_line = [&](auto& p1, auto& p2) {
+        context.painter().draw_line({ (int)p1.x(), (int)p1.y() }, { (int)p2.x(), (int)p2.y() }, color, 1, gfx_line_style);
+    };
+
+    float p1_step = 0;
+    float p2_step = 0;
+
+    switch (edge) {
+    case BorderEdge::Top:
+        p1_step = style.border_left().width / (float)int_width;
+        p2_step = style.border_right().width / (float)int_width;
+        for (int i = 0; i < int_width; ++i) {
+            draw_line(p1, p2);
+            p1.move_by(p1_step, 1);
+            p2.move_by(-p2_step, 1);
+        }
+        break;
+    case BorderEdge::Right:
+        p1_step = style.border_top().width / (float)int_width;
+        p2_step = style.border_bottom().width / (float)int_width;
+        for (int i = int_width - 1; i >= 0; --i) {
+            draw_line(p1, p2);
+            p1.move_by(-1, p1_step);
+            p2.move_by(-1, -p2_step);
+        }
+        break;
+    case BorderEdge::Bottom:
+        p1_step = style.border_left().width / (float)int_width;
+        p2_step = style.border_right().width / (float)int_width;
+        for (int i = int_width - 1; i >= 0; --i) {
+            draw_line(p1, p2);
+            p1.move_by(p1_step, -1);
+            p2.move_by(-p2_step, -1);
+        }
+        break;
+    case BorderEdge::Left:
+        p1_step = style.border_top().width / (float)int_width;
+        p2_step = style.border_bottom().width / (float)int_width;
+        for (int i = 0; i < int_width; ++i) {
+            draw_line(p1, p2);
+            p1.move_by(1, p1_step);
+            p2.move_by(1, -p2_step);
+        }
+        break;
+    }
+}
+
+}
diff --git a/Libraries/LibWeb/Painting/BorderPainting.h b/Libraries/LibWeb/Painting/BorderPainting.h
new file mode 100644
index 0000000000..68b4c2c7f0
--- /dev/null
+++ b/Libraries/LibWeb/Painting/BorderPainting.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibGfx/Forward.h>
+#include <LibWeb/Layout/LayoutStyle.h>
+
+namespace Web::Painting {
+
+enum class BorderEdge {
+    Top,
+    Right,
+    Bottom,
+    Left,
+};
+void paint_border(PaintContext&, BorderEdge, const Gfx::FloatRect&, const LayoutStyle&);
+
+}