LibGfx+LibWeb: Add Path::glyph_run() and use in canvas

Canvas text painting needs to support per-glyph font fallbacks, which
means we can't hand over responsibility for text shaping to Skia and
instead need to extract glyph paths from our own shaped GlyphRun.

Libraries/LibGfx/Forward.h

@@ -15,6 +15,7 @@ class Color;
 
 class Emoji;
 class Font;
+class GlyphRun;
 class ImageDecoder;
 struct FontPixelMetrics;
 

Libraries/LibGfx/Path.h

@@ -33,6 +33,7 @@ public:
     virtual void quadratic_bezier_curve_to(FloatPoint through, FloatPoint point) = 0;
     virtual void cubic_bezier_curve_to(FloatPoint c1, FloatPoint c2, FloatPoint p2) = 0;
     virtual void text(Utf8View, Font const&) = 0;
+    virtual void glyph_run(GlyphRun const&) = 0;
 
     virtual void append_path(Gfx::Path const&) = 0;
     virtual void intersect(Gfx::Path const&) = 0;
@@ -90,6 +91,7 @@ public:
     void quadratic_bezier_curve_to(FloatPoint through, FloatPoint point) { impl().quadratic_bezier_curve_to(through, point); }
     void cubic_bezier_curve_to(FloatPoint c1, FloatPoint c2, FloatPoint p2) { impl().cubic_bezier_curve_to(c1, c2, p2); }
     void text(Utf8View text, Font const& font) { impl().text(text, font); }
+    void glyph_run(GlyphRun const& glyph_run) { impl().glyph_run(glyph_run); }
 
     void horizontal_line_to(float x) { line_to({ x, last_point().y() }); }
     void vertical_line_to(float y) { line_to({ last_point().x(), y }); }

Libraries/LibGfx/PathSkia.cpp

@@ -11,6 +11,7 @@
 #include <LibGfx/PathSkia.h>
 #include <LibGfx/Rect.h>
 #include <LibGfx/SkiaUtils.h>
+#include <LibGfx/TextLayout.h>
 #include <core/SkFont.h>
 #include <core/SkPath.h>
 #include <core/SkPathMeasure.h>
@@ -139,6 +140,21 @@ void PathImplSkia::text(Utf8View string, Font const& font)
 {
     SkTextUtils::GetPath(string.as_string().characters_without_null_termination(), string.as_string().length(), SkTextEncoding::kUTF8, last_point().x(), last_point().y(), font.skia_font(1), m_path.ptr());
 }
+
+void PathImplSkia::glyph_run(GlyphRun const& glyph_run)
+{
+    auto sk_font = glyph_run.font().skia_font(1);
+    m_path->setFillType(SkPathFillType::kWinding);
+    auto font_ascent = glyph_run.font().pixel_metrics().ascent;
+    for (auto const& glyph : glyph_run.glyphs()) {
+        SkPath glyph_path;
+        if (!sk_font.getPath(static_cast<SkGlyphID>(glyph.glyph_id), &glyph_path))
+            continue;
+        glyph_path.offset(glyph.position.x(), glyph.position.y() + font_ascent);
+        m_path->addPath(glyph_path);
+    }
+}
+
 NonnullOwnPtr<PathImpl> PathImplSkia::place_text_along(Utf8View text, Font const& font) const
 {
     auto sk_font = font.skia_font(1);

Libraries/LibGfx/PathSkia.h

@@ -28,6 +28,7 @@ public:
     virtual void quadratic_bezier_curve_to(FloatPoint through, FloatPoint point) override;
     virtual void cubic_bezier_curve_to(FloatPoint c1, FloatPoint c2, FloatPoint p2) override;
     virtual void text(Utf8View, Font const&) override;
+    virtual void glyph_run(GlyphRun const&) override;
 
     virtual void append_path(Gfx::Path const&) override;
     virtual void intersect(Gfx::Path const&) override;

Libraries/LibWeb/HTML/CanvasRenderingContext2D.cpp

@@ -235,8 +235,8 @@ Gfx::Path CanvasRenderingContext2D::text_path(StringView text, float x, float y,
     auto const& font = font_cascade_list()->first();
 
     Gfx::Path path;
-    path.move_to({ x, y });
-    path.text(Utf8View { text }, font);
+    auto glyph_run = Gfx::shape_text({ x, y }, 0, Utf8View(text), font, Gfx::GlyphRun::TextType::Ltr, {});
+    path.glyph_run(*glyph_run);
 
     auto text_width = path.bounding_box().width();
     Gfx::AffineTransform transform = {};