From 4f4bd3793faa91c3532656536536d431764acdee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julian=20Offenh=C3=A4user?= <offenhaeuser@protonmail.com>
Date: Thu, 9 Feb 2023 14:16:22 +0100
Subject: [PATCH] LibPDF: Fix glyph sizing bug that caused incorrect spacing

When loading OpenType fonts, either as a replacement for the standard
14 fonts or an embedded one, we previously passed the font size as the
_point_ size to the loader class. The difference is quite subtle, being
that Gfx::ScaledFont uses the optional dpi parameter to convert the
input from inches to pixels.

This meant that our glyphs were exactly 1.333% too large, causing them
to overlap in places.
---
 Userland/Libraries/LibPDF/Fonts/PDFFont.cpp      |  9 +++++----
 Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp | 14 +++++++-------
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/Userland/Libraries/LibPDF/Fonts/PDFFont.cpp b/Userland/Libraries/LibPDF/Fonts/PDFFont.cpp
index 6fb17c17ae..5fdf3a4b63 100644
--- a/Userland/Libraries/LibPDF/Fonts/PDFFont.cpp
+++ b/Userland/Libraries/LibPDF/Fonts/PDFFont.cpp
@@ -33,10 +33,11 @@ static bool is_standard_latin_font(DeprecatedFlyString const& font)
 
 PDFErrorOr<void> PDFFont::CommonData::load_from_dict(Document* document, NonnullRefPtr<DictObject> dict, float font_size)
 {
-    base_font_name = TRY(dict->get_name(document, CommonNames::BaseFont))->name();
-    if ((is_standard_font = is_standard_latin_font(base_font_name))) {
-        auto replacement = replacement_for_standard_latin_font(base_font_name.to_lowercase());
-        font = Gfx::FontDatabase::the().get(replacement.get<0>(), replacement.get<1>(), font_size);
+    auto base_font = TRY(dict->get_name(document, CommonNames::BaseFont))->name();
+    if ((is_standard_font = is_standard_latin_font(base_font))) {
+        auto replacement = replacement_for_standard_latin_font(base_font);
+        float point_size = (font_size * POINTS_PER_INCH) / DEFAULT_DPI;
+        font = Gfx::FontDatabase::the().get(replacement.get<0>(), replacement.get<1>(), point_size);
         VERIFY(font);
     }
 
diff --git a/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp b/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp
index 527f11bd6c..5cd2bc7bee 100644
--- a/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp
+++ b/Userland/Libraries/LibPDF/Fonts/TrueTypeFont.cpp
@@ -19,13 +19,13 @@ PDFErrorOr<PDFFont::CommonData> TrueTypeFont::parse_data(Document* document, Non
     TRY(data.load_from_dict(document, dict, font_size));
 
     if (!data.is_standard_font) {
-        auto descriptor = MUST(dict->get_dict(document, CommonNames::FontDescriptor));
-        if (!descriptor->contains(CommonNames::FontFile2))
-            return data;
-
-        auto font_file_stream = TRY(descriptor->get_stream(document, CommonNames::FontFile2));
-        auto ttf_font = TRY(OpenType::Font::try_load_from_externally_owned_memory(font_file_stream->bytes()));
-        data.font = adopt_ref(*new Gfx::ScaledFont(*ttf_font, font_size, font_size));
+        auto descriptor = TRY(dict->get_dict(document, CommonNames::FontDescriptor));
+        if (descriptor->contains(CommonNames::FontFile2)) {
+            auto font_file_stream = TRY(descriptor->get_stream(document, CommonNames::FontFile2));
+            auto ttf_font = TRY(OpenType::Font::try_load_from_externally_owned_memory(font_file_stream->bytes()));
+            float point_size = (font_size * POINTS_PER_INCH) / DEFAULT_DPI;
+            data.font = adopt_ref(*new Gfx::ScaledFont(*ttf_font, point_size, point_size));
+        }
     }
 
     return data;