LibWeb: Scale the font when painting the text on buttons

Button text was staying the same size at all zoom levels. :^)

Userland/Libraries/LibWeb/FontCache.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/DeprecatedFlyString.h>
 #include <LibGfx/Font/Font.h>
 #include <LibWeb/FontCache.h>
 
@@ -21,6 +22,22 @@ RefPtr<Gfx::Font const> FontCache::get(FontSelector const& font_selector) const
     return nullptr;
 }
 
+NonnullRefPtr<Gfx::Font const> FontCache::scaled_font(Gfx::Font const& font, float scale_factor)
+{
+    auto device_font_pt_size = font.point_size() * scale_factor;
+    FontSelector font_selector = { FlyString::from_deprecated_fly_string(font.family()).release_value_but_fixme_should_propagate_errors(), device_font_pt_size, font.weight(), font.width(), font.slope() };
+    if (auto cached_font = FontCache::the().get(font_selector)) {
+        return *cached_font;
+    }
+
+    if (auto font_with_device_pt_size = font.with_size(device_font_pt_size)) {
+        set(font_selector, *font_with_device_pt_size);
+        return font_with_device_pt_size.release_nonnull();
+    }
+
+    return font;
+}
+
 void FontCache::set(FontSelector const& font_selector, NonnullRefPtr<Gfx::Font const> font)
 {
     m_fonts.set(font_selector, move(font));

Userland/Libraries/LibWeb/FontCache.h

@@ -37,6 +37,8 @@ public:
     RefPtr<Gfx::Font const> get(FontSelector const&) const;
     void set(FontSelector const&, NonnullRefPtr<Gfx::Font const>);
 
+    NonnullRefPtr<Gfx::Font const> scaled_font(Gfx::Font const&, float scale_factor);
+
 private:
     FontCache() = default;
     mutable HashMap<FontSelector, NonnullRefPtr<Gfx::Font const>> m_fonts;

Userland/Libraries/LibWeb/Painting/ButtonPaintable.cpp

@@ -5,6 +5,7 @@
  */
 
 #include <LibGUI/Event.h>
+#include <LibWeb/FontCache.h>
 #include <LibWeb/HTML/BrowsingContext.h>
 #include <LibWeb/HTML/HTMLImageElement.h>
 #include <LibWeb/Layout/ButtonBox.h>
@@ -47,7 +48,12 @@ void ButtonPaintable::paint(PaintContext& context, PaintPhase phase) const
             auto offset = context.rounded_device_pixels(1);
             text_rect.translate_by(offset, offset);
         }
-        context.painter().draw_text(text_rect.to_type<int>(), static_cast<HTML::HTMLInputElement const&>(dom_node).value(), layout_box().font(), Gfx::TextAlignment::Center, computed_values().color());
+        context.painter().draw_text(
+            text_rect.to_type<int>(),
+            static_cast<HTML::HTMLInputElement const&>(dom_node).value(),
+            FontCache::the().scaled_font(layout_box().font(), context.device_pixels_per_css_pixel()),
+            Gfx::TextAlignment::Center,
+            computed_values().color());
     }
 }
 

Userland/Libraries/LibWeb/Painting/PaintableBox.cpp

@@ -525,30 +525,16 @@ static void paint_text_fragment(PaintContext& context, Layout::TextNode const& t
         DevicePixelPoint baseline_start { fragment_absolute_device_rect.x(), fragment_absolute_device_rect.y() + context.rounded_device_pixels(fragment.baseline()) };
         Utf8View view { text.substring_view(fragment.start(), fragment.length()) };
 
-        auto& font = fragment.layout_node().font();
-        auto scaled_font = [&]() -> RefPtr<Gfx::Font const> {
-            auto device_font_pt_size = font.point_size() * context.device_pixels_per_css_pixel();
-            FontSelector font_selector = { FlyString::from_deprecated_fly_string(font.family()).release_value_but_fixme_should_propagate_errors(), device_font_pt_size, font.weight(), font.width(), font.slope() };
-            if (auto cached_font = FontCache::the().get(font_selector)) {
-                return cached_font;
-            }
-
-            if (auto font_with_device_pt_size = font.with_size(device_font_pt_size)) {
-                FontCache::the().set(font_selector, *font_with_device_pt_size);
-                return font_with_device_pt_size;
-            }
-
-            return {};
-        }();
+        auto scaled_font = FontCache::the().scaled_font(fragment.layout_node().font(), context.device_pixels_per_css_pixel());
 
-        painter.draw_text_run(baseline_start.to_type<int>(), view, scaled_font ? *scaled_font : font, text_node.computed_values().color());
+        painter.draw_text_run(baseline_start.to_type<int>(), view, *scaled_font, text_node.computed_values().color());
 
         auto selection_rect = context.enclosing_device_rect(fragment.selection_rect(text_node.font())).to_type<int>();
         if (!selection_rect.is_empty()) {
             painter.fill_rect(selection_rect, context.palette().selection());
             Gfx::PainterStateSaver saver(painter);
             painter.add_clip_rect(selection_rect);
-            painter.draw_text_run(baseline_start.to_type<int>(), view, scaled_font ? *scaled_font : font, context.palette().selection_text());
+            painter.draw_text_run(baseline_start.to_type<int>(), view, *scaled_font, context.palette().selection_text());
         }
 
         paint_text_decoration(context, painter, text_node, fragment);