LibPDF: Refactor *Font classes

The PDFFont class hierarchy was very simple (a top-level PDFFont class,
followed by all the children classes that derived directly from it).
While this design was good enough for some things, it didn't correctly
model the actual organization of font types:

 * PDF fonts are first divided between "simple" and "composite" fonts.
   The latter is the Type0 font, while the rest are all simple.
 * PDF fonts yield a glyph per "character code". Simple fonts char codes
   are always 1 byte long, while Type0 char codes are of variable size.

To this effect, this commit changes the hierarchy of Font classes,
introducing a new SimpleFont class, deriving from PDFFont, and acting as
the parent of Type1Font and TrueTypeFont, while Type0 still derives from
PDFFont directly. This distinction allows us now to:

 * Model string rendering differently from simple and composite fonts:
   PDFFont now offers a generic draw_string method that takes a whole
   string to be rendered instead of a single char code. SimpleFont
   implements this as a loop over individual bytes of the string, with
   T1 and TT implementing draw_glyph for drawing a single char code.
 * Some common fields between T1 and TT fonts now live under SimpleFont
   instead of under PDFfont, where they previously resided.
 * Some other interfaces specific to SimpleFont have been cleaned up,
   with u16/u32 not appearing on these classes (or in PDFFont) anymore.
 * Type0Font's rendering still remains unimplemented.

As part of this exercise I also took the chance to perform the following
cleanups and restructurings:

 * Refactored the creation and initialisation of fonts. They are all
   centrally created at PDFFont::create, with a virtual "initialize"
   method that allows them to initialise their inner members in the
   correct order (parent first, child later) after creation.
 * Removed duplicated code.
 * Cleaned up some public interfaces: receive const refs, removed
   unnecessary ctro/dtors, etc.
 * Slightly changed how Type1 and TrueType fonts are implemented: if
   there's an embedded font that takes priority, otherwise we always
   look for a replacement.
 * This means we don't do anything special for the standard fonts. The
   only behavior previously associated to standard fonts was choosing an
   encoding, and even that was under questioning.

1 files changed, 3 insertions, 14 deletions

diff --git a/Userland/Libraries/LibPDF/Renderer.cpp b/Userland/Libraries/LibPDF/Renderer.cpp
index 91b93ed0de..98f2d2a206 100644
--- a/Userland/Libraries/LibPDF/Renderer.cpp
+++ b/Userland/Libraries/LibPDF/Renderer.cpp
@@ -730,22 +730,11 @@ PDFErrorOr<void> Renderer::show_text(DeprecatedString const& string)
 
     auto font_size = text_rendering_matrix.x_scale() * text_state().font_size;
 
-    auto glyph_position = text_rendering_matrix.map(Gfx::FloatPoint { 0.0f, 0.0f });
-
-    auto original_position = glyph_position;
-
-    for (auto char_code : string.bytes()) {
-        auto char_width = text_state().font->get_char_width(char_code);
-        auto glyph_width = char_width * font_size;
-        text_state().font->draw_glyph(m_painter, glyph_position, glyph_width, char_code, state().paint_color);
-        auto tx = glyph_width;
-        tx += text_state().character_spacing;
-        tx *= text_state().horizontal_scaling;
-        glyph_position += { tx, 0.0f };
-    }
+    auto start_position = text_rendering_matrix.map(Gfx::FloatPoint { 0.0f, 0.0f });
+    auto end_position = TRY(text_state().font->draw_string(m_painter, start_position, string, state().paint_color, font_size, text_state().character_spacing, text_state().horizontal_scaling));
 
     // Update text matrix
-    auto delta_x = glyph_position.x() - original_position.x();
+    auto delta_x = end_position.x() - start_position.x();
     m_text_rendering_matrix_is_dirty = true;
     m_text_matrix.translate(delta_x / text_rendering_matrix.x_scale(), 0.0f);
     return {};