LibPDF: Ask OpenType font programs for glyph widths if needed

If the font dictionary didn't specify custom glyph widths, we would fall
back to the specified "missing width" (or 0 in most cases!), which meant
that we would draw glyphs on top of each other in a lot of cases, namely
for TrueTypeFonts or standard Type1Fonts with an OpenType fallback.

What we actually want to do in this case is ask the OpenType font for
the correct width.

6 files changed, 21 insertions, 12 deletions

diff --git a/Userland/Libraries/LibPDF/Fonts/SimpleFont.cpp b/Userland/Libraries/LibPDF/Fonts/SimpleFont.cpp
index 358e22024a..303aef9d08 100644
--- a/Userland/Libraries/LibPDF/Fonts/SimpleFont.cpp
+++ b/Userland/Libraries/LibPDF/Fonts/SimpleFont.cpp
@@ -45,17 +45,18 @@ PDFErrorOr<void> SimpleFont::initialize(Document* document, NonnullRefPtr<DictOb
     return {};
 }
 
-float SimpleFont::get_char_width(u8 char_code) const
-{
-    return static_cast<float>(m_widths.get(char_code).value_or(m_missing_width)) / 1000.0f;
-}
-
 PDFErrorOr<Gfx::FloatPoint> SimpleFont::draw_string(Gfx::Painter& painter, Gfx::FloatPoint glyph_position, DeprecatedString const& string, Color const& paint_color, float font_size, float character_spacing, float horizontal_scaling)
 {
     auto so = make_object<StringObject>(string, true);
     for (auto char_code : string.bytes()) {
-        auto char_width = get_char_width(char_code);
-        auto glyph_width = char_width * font_size;
+        // Use the width specified in the font's dictionary if available,
+        // and use the default width for the given font otherwise.
+        float glyph_width;
+        if (auto width = m_widths.get(char_code); width.has_value())
+            glyph_width = font_size * width.value() / 1000.0f;
+        else
+            glyph_width = get_glyph_width(char_code);
+
         draw_glyph(painter, glyph_position, glyph_width, char_code, paint_color);
         auto tx = glyph_width;
         tx += character_spacing;
diff --git a/Userland/Libraries/LibPDF/Fonts/SimpleFont.h b/Userland/Libraries/LibPDF/Fonts/SimpleFont.h
index 61bc7b2eed..8137a2ef46 100644
--- a/Userland/Libraries/LibPDF/Fonts/SimpleFont.h
+++ b/Userland/Libraries/LibPDF/Fonts/SimpleFont.h
@@ -17,13 +17,12 @@ public:
 
 protected:
     PDFErrorOr<void> initialize(Document* document, NonnullRefPtr<DictObject> const& dict, float font_size) override;
+    virtual float get_glyph_width(u8 char_code) const = 0;
     virtual void draw_glyph(Gfx::Painter& painter, Gfx::FloatPoint point, float width, u8 char_code, Color color) = 0;
     RefPtr<Encoding>& encoding() { return m_encoding; }
     RefPtr<Encoding> const& encoding() const { return m_encoding; }
 
 private:
-    float get_char_width(u8 char_code) const;
-
     RefPtr<Encoding> m_encoding;
     RefPtr<StreamObject> m_to_unicode;
     HashMap<u8, u16> m_widths;
diff --git a/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp b/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp
index 6a943a08c4..a35680bd51 100644
--- a/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp
+++ b/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp
@@ -30,11 +30,13 @@ PDFErrorOr<void> TrueTypeFont::initialize(Document* document, NonnullRefPtr<Dict
     return {};
 }
 
-void TrueTypeFont::draw_glyph(Gfx::Painter& painter, Gfx::FloatPoint point, float, u8 char_code, Color color)
+float TrueTypeFont::get_glyph_width(u8 char_code) const
 {
-    if (!m_font)
-        return;
+    return m_font->glyph_width(char_code);
+}
 
+void TrueTypeFont::draw_glyph(Gfx::Painter& painter, Gfx::FloatPoint point, float, u8 char_code, Color color)
+{
     // Account for the reversed font baseline
     auto position = point.translated(0, -m_font->baseline());
     painter.draw_glyph(position, char_code, *m_font, color);
diff --git a/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.h b/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.h
index 02fba97f5b..240b7da4fe 100644
--- a/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.h
+++ b/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.h
@@ -14,6 +14,7 @@ namespace PDF {
 
 class TrueTypeFont : public SimpleFont {
 public:
+    float get_glyph_width(u8 char_code) const override;
     void draw_glyph(Gfx::Painter&, Gfx::FloatPoint, float, u8, Color) override;
     Type type() const override { return PDFFont::Type::TrueType; }
 
diff --git a/Userland/Libraries/LibPDF/Fonts/Type1Font.cpp b/Userland/Libraries/LibPDF/Fonts/Type1Font.cpp
index 49a828e3d8..c9cf6c2e05 100644
--- a/Userland/Libraries/LibPDF/Fonts/Type1Font.cpp
+++ b/Userland/Libraries/LibPDF/Fonts/Type1Font.cpp
@@ -49,6 +49,11 @@ PDFErrorOr<void> Type1Font::initialize(Document* document, NonnullRefPtr<DictObj
     return {};
 }
 
+float Type1Font::get_glyph_width(u8 char_code) const
+{
+    return m_font->glyph_width(char_code);
+}
+
 void Type1Font::draw_glyph(Gfx::Painter& painter, Gfx::FloatPoint point, float width, u8 char_code, Color color)
 {
     if (!m_font_program) {
diff --git a/Userland/Libraries/LibPDF/Fonts/Type1Font.h b/Userland/Libraries/LibPDF/Fonts/Type1Font.h
index c85df6d7b0..c780804323 100644
--- a/Userland/Libraries/LibPDF/Fonts/Type1Font.h
+++ b/Userland/Libraries/LibPDF/Fonts/Type1Font.h
@@ -14,6 +14,7 @@ namespace PDF {
 
 class Type1Font : public SimpleFont {
 public:
+    float get_glyph_width(u8 char_code) const override;
     void draw_glyph(Gfx::Painter& painter, Gfx::FloatPoint point, float width, u8 char_code, Color color) override;
     Type type() const override { return PDFFont::Type::Type1; }