LibGfx: Always load font widths array and use it for glyph presence

Since we were always saving the glyph widths array to the font file, we
now also always load it, even on (which also simplifies the logic a bit)
fixed width fonts. We also set it initially to 0 instead of the default
fixed width, which allows us to use it to check for glyph presence in
both fixed width and variable width fonts.

Userland/Libraries/LibGfx/BitmapFont.cpp

@@ -63,10 +63,7 @@ NonnullRefPtr<Font> BitmapFont::clone() const
     auto* new_rows = static_cast<unsigned*>(malloc(bytes_per_glyph * m_glyph_count));
     memcpy(new_rows, m_rows, bytes_per_glyph * m_glyph_count);
     auto* new_widths = static_cast<u8*>(malloc(m_glyph_count));
-    if (m_glyph_widths)
-        memcpy(new_widths, m_glyph_widths, m_glyph_count);
-    else
-        memset(new_widths, m_glyph_width, m_glyph_count);
+    memcpy(new_widths, m_glyph_widths, m_glyph_count);
     return adopt(*new BitmapFont(m_name, m_family, new_rows, new_widths, m_fixed_width, m_glyph_width, m_glyph_height, m_glyph_spacing, m_type, m_baseline, m_mean_line, m_presentation_size, m_weight, true));
 }
 
@@ -77,7 +74,7 @@ NonnullRefPtr<BitmapFont> BitmapFont::create(u8 glyph_height, u8 glyph_width, bo
     auto* new_rows = static_cast<unsigned*>(malloc(bytes_per_glyph * count));
     memset(new_rows, 0, bytes_per_glyph * count);
     auto* new_widths = static_cast<u8*>(malloc(count));
-    memset(new_widths, glyph_width, count);
+    memset(new_widths, 0, count);
     return adopt(*new BitmapFont("Untitled", "Untitled", new_rows, new_widths, fixed, glyph_width, glyph_height, 1, type, 0, 0, 0, 400, true));
 }
 
@@ -99,6 +96,9 @@ BitmapFont::BitmapFont(String name, String family, unsigned* rows, u8* widths, b
     , m_fixed_width(is_fixed_width)
     , m_owns_arrays(owns_arrays)
 {
+    VERIFY(m_rows);
+    VERIFY(m_glyph_widths);
+
     update_x_height();
 
     m_glyph_count = glyph_count_by_type(m_type);
@@ -111,7 +111,7 @@ BitmapFont::BitmapFont(String name, String family, unsigned* rows, u8* widths, b
             maximum = max(maximum, m_glyph_widths[i]);
         }
         m_min_glyph_width = minimum;
-        m_max_glyph_width = maximum;
+        m_max_glyph_width = max(maximum, m_glyph_width);
     }
 }
 
@@ -156,9 +156,7 @@ RefPtr<BitmapFont> BitmapFont::load_from_memory(const u8* data)
     size_t bytes_per_glyph = sizeof(unsigned) * header.glyph_height;
 
     auto* rows = const_cast<unsigned*>((const unsigned*)(data + sizeof(FontFileHeader)));
-    u8* widths = nullptr;
-    if (header.is_variable_width)
-        widths = (u8*)(rows) + count * bytes_per_glyph;
+    u8* widths = (u8*)(rows) + count * bytes_per_glyph;
     return adopt(*new BitmapFont(String(header.name), String(header.family), rows, widths, !header.is_variable_width, header.glyph_width, header.glyph_height, header.glyph_spacing, type, header.baseline, header.mean_line, header.presentation_size, header.weight));
 }