LibGfx+LibWeb: Allow inexact size lookups when requesting scaled fonts

For bitmap fonts, we will often not have an exact match for requested
sizes. Return the closest match instead of a nullptr.

LibWeb is currently the only user of this API. If it needs to be
configurable in the future to only allow exact matches, we can add a
parameter or another method at that time.

Userland/Libraries/LibGfx/Font/BitmapFont.cpp

@@ -410,9 +410,12 @@ String BitmapFont::variant() const
     return MUST(builder.to_string());
 }
 
-RefPtr<Font> BitmapFont::with_size(float point_size) const
+NonnullRefPtr<Font> BitmapFont::with_size(float point_size) const
 {
-    return Gfx::FontDatabase::the().get(family(), point_size, weight(), width(), slope());
+    auto scaled_font = Gfx::FontDatabase::the().get(family(), point_size, weight(), width(), slope(), AllowInexactSizeMatch::Yes);
+    VERIFY(scaled_font); // The inexact lookup should, at the very least, return `this` font.
+
+    return *scaled_font;
 }
 
 Font const& Font::bold_variant() const

Userland/Libraries/LibGfx/Font/BitmapFont.h

@@ -130,7 +130,7 @@ public:
     virtual String qualified_name() const override;
     virtual String human_readable_name() const override { return MUST(String::formatted("{} {} {}", family(), variant(), presentation_size())); }
 
-    virtual RefPtr<Font> with_size(float point_size) const override;
+    virtual NonnullRefPtr<Font> with_size(float point_size) const override;
 
 private:
     BitmapFont(String name, String family, Bytes rows, Span<u8> widths, bool is_fixed_width,

Userland/Libraries/LibGfx/Font/Font.h

@@ -212,7 +212,7 @@ public:
     virtual String qualified_name() const = 0;
     virtual String human_readable_name() const = 0;
 
-    virtual RefPtr<Font> with_size(float point_size) const = 0;
+    virtual NonnullRefPtr<Font> with_size(float point_size) const = 0;
 
     Font const& bold_variant() const;
 

Userland/Libraries/LibGfx/Font/ScaledFont.cpp

@@ -159,7 +159,7 @@ NonnullRefPtr<ScaledFont> ScaledFont::scaled_with_size(float point_size) const
     return m_font->scaled_font(point_size);
 }
 
-RefPtr<Font> ScaledFont::with_size(float point_size) const
+NonnullRefPtr<Font> ScaledFont::with_size(float point_size) const
 {
     return scaled_with_size(point_size);
 }

Userland/Libraries/LibGfx/Font/ScaledFont.h

@@ -70,7 +70,7 @@ public:
     virtual String human_readable_name() const override { return MUST(String::formatted("{} {} {}", family(), variant(), presentation_size())); }
 
     virtual NonnullRefPtr<ScaledFont> scaled_with_size(float point_size) const;
-    virtual RefPtr<Font> with_size(float point_size) const override;
+    virtual NonnullRefPtr<Font> with_size(float point_size) const override;
 
     virtual bool has_color_bitmaps() const override { return m_font->has_color_bitmaps(); }
 

Userland/Libraries/LibWeb/CSS/StyleComputer.cpp

@@ -2089,11 +2089,7 @@ RefPtr<Gfx::FontCascadeList const> StyleComputer::compute_font_for_style_values(
     }
 
     auto found_font = StyleProperties::font_fallback(monospace, bold);
-    if (auto scaled_fallback_font = found_font->with_size(font_size_in_pt)) {
-        font_list->add(*scaled_fallback_font);
-    } else {
-        font_list->add(*found_font);
-    }
+    font_list->add(found_font->with_size(font_size_in_pt));
 
     return font_list;
 }

Userland/Libraries/LibWeb/Layout/Node.h

@@ -272,7 +272,7 @@ inline Gfx::Font const& Node::scaled_font(PaintContext& context) const
 inline Gfx::Font const& Node::scaled_font(float scale_factor) const
 {
     auto const& font = first_available_font();
-    return *font.with_size(font.point_size() * scale_factor);
+    return font.with_size(font.point_size() * scale_factor);
 }
 
 inline const CSS::ImmutableComputedValues& Node::computed_values() const

Userland/Libraries/LibWeb/Painting/BackgroundPainting.cpp

@@ -66,7 +66,7 @@ static Vector<Gfx::Path> compute_text_clip_paths(PaintContext& context, Paintabl
         Gfx::Path glyph_run_path;
         for (auto glyph : fragment.glyph_run().glyphs()) {
             glyph.visit([&](auto& glyph) {
-                glyph.font = *glyph.font->with_size(glyph.font->point_size() * static_cast<float>(context.device_pixels_per_css_pixel()));
+                glyph.font = glyph.font->with_size(glyph.font->point_size() * static_cast<float>(context.device_pixels_per_css_pixel()));
                 glyph.position = glyph.position.scaled(context.device_pixels_per_css_pixel());
             });
 

Userland/Libraries/LibWeb/Painting/CommandExecutorCPU.cpp

@@ -31,7 +31,7 @@ CommandResult CommandExecutorCPU::draw_glyph_run(Vector<Gfx::DrawGlyphOrEmoji> c
         auto transformed_glyph = glyph_or_emoji;
         transformed_glyph.visit([&](auto& glyph) {
             glyph.position = glyph.position.scaled(scale).translated(translation);
-            glyph.font = *glyph.font->with_size(glyph.font->point_size() * static_cast<float>(scale));
+            glyph.font = glyph.font->with_size(glyph.font->point_size() * static_cast<float>(scale));
         });
         if (glyph_or_emoji.has<Gfx::DrawGlyph>()) {
             auto& glyph = transformed_glyph.get<Gfx::DrawGlyph>();

Userland/Libraries/LibWeb/Painting/CommandExecutorGPU.cpp

@@ -39,7 +39,7 @@ CommandResult CommandExecutorGPU::draw_glyph_run(Vector<Gfx::DrawGlyphOrEmoji> c
         auto transformed_glyph = glyph;
         transformed_glyph.visit([&](auto& glyph) {
             glyph.position = glyph.position.scaled(scale).translated(translation);
-            glyph.font = *glyph.font->with_size(glyph.font->point_size() * static_cast<float>(scale));
+            glyph.font = glyph.font->with_size(glyph.font->point_size() * static_cast<float>(scale));
         });
         transformed_glyph_run.append(transformed_glyph);
     }

Userland/Libraries/LibWeb/Painting/CommandList.cpp

@@ -89,8 +89,8 @@ void CommandList::execute(CommandExecutor& executor)
                 for (auto const& glyph_or_emoji : command.get<DrawGlyphRun>().glyph_run->glyphs()) {
                     if (glyph_or_emoji.has<Gfx::DrawGlyph>()) {
                         auto const& glyph = glyph_or_emoji.get<Gfx::DrawGlyph>();
-                        auto const& font = *glyph.font->with_size(glyph.font->point_size() * static_cast<float>(scale));
-                        unique_glyphs.ensure(&font, [] { return HashTable<u32> {}; }).set(glyph.code_point);
+                        auto font = glyph.font->with_size(glyph.font->point_size() * static_cast<float>(scale));
+                        unique_glyphs.ensure(font, [] { return HashTable<u32> {}; }).set(glyph.code_point);
                     }
                 }
             }

Userland/Libraries/LibWeb/Painting/ShadowPainting.cpp

@@ -593,7 +593,7 @@ void paint_text_shadow(PaintContext& context, PaintableFragment const& fragment,
     scaled_glyph_run.ensure_capacity(fragment.glyph_run().glyphs().size());
     for (auto glyph : fragment.glyph_run().glyphs()) {
         glyph.visit([&](auto& glyph) {
-            glyph.font = *glyph.font->with_size(glyph.font->point_size() * static_cast<float>(context.device_pixels_per_css_pixel()));
+            glyph.font = glyph.font->with_size(glyph.font->point_size() * static_cast<float>(context.device_pixels_per_css_pixel()));
             glyph.position = glyph.position.scaled(context.device_pixels_per_css_pixel());
         });
         scaled_glyph_run.append(move(glyph));