Start using level-specific font where needed, make CJK tweaks

Level text such as room names, text box content, and the contents of
the script editor need to be displayed in the level-specific font, and
tweaked to look right. This involves displaying less lines in the
script editor, making text boxes bigger, displaying some text higher
and some text lower. This is still unfinished, but it's the real start
of a migration to font::print functions!

desktop_version/src/Font.cpp

@@ -118,6 +118,11 @@ static GlyphInfo* find_glyphinfo(const Font* f, const uint32_t codepoint)
 int get_advance(const Font* f, const uint32_t codepoint)
 {
     // Get the width of a single character in a font
+    if (f == NULL)
+    {
+        return 8;
+    }
+
     GlyphInfo* glyph = find_glyphinfo(f, codepoint);
     if (glyph == NULL)
     {
@@ -341,7 +346,8 @@ static bool find_font_by_name(FontContainer* container, const char* name, size_t
 
 static void set_custom_font(const char* name)
 {
-    /* Apply the choice for a certain level-specific font */
+    /* Apply the choice for a certain level-specific font. */
+
     if (find_font_by_name(&fonts_custom, name, &font_idx_custom))
     {
         font_idx_custom_is_custom = true;
@@ -693,11 +699,59 @@ static int print_char(
     return glyph->advance * scale;
 }
 
+static Font* container_get(FontContainer* container, size_t idx)
+{
+    /* Get a certain font from the given container (with bounds checking).
+     * Does its best to return at least something,
+     * but if there are no fonts whatsoever, can return NULL. */
+
+    if (idx < container->count)
+    {
+        return &container->fonts[idx];
+    }
+    if (font_idx_8x8 < fonts_main.count)
+    {
+        return &fonts_main.fonts[font_idx_8x8];
+    }
+    if (fonts_main.count > 0)
+    {
+        return &fonts_main.fonts[0];
+    }
+    return NULL;
+}
+
 static Font* fontsel_to_font(int sel)
 {
-    /* Take font selection integer (0-31) and turn it into the correct Font */
-    // TODO handle all these cases here like 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 etc
-    return &fonts_main.fonts[font_idx_8x8];
+    /* Take font selection integer (0-31) and turn it into the correct Font
+     * 0: PR_FONT_INTERFACE - use interface font
+     * 1: PR_FONT_LEVEL     - use level font
+     * 2: PR_FONT_8X8       - use 8x8 font no matter what
+     * 3-31:                - use (main) font index 0-28 */
+
+    if (sel < 0)
+    {
+        /* Shouldn't happen but better safe than sorry... */
+        return NULL;
+    }
+
+    switch (sel)
+    {
+    case 0:
+        return container_get(&fonts_main, font_idx_interface);
+    case 1:
+        if (font_idx_custom_is_custom)
+        {
+            return container_get(&fonts_custom, font_idx_custom);
+        }
+        else
+        {
+            return container_get(&fonts_main, font_idx_custom);
+        }
+    case 2:
+        return container_get(&fonts_main, font_idx_8x8);
+    }
+
+    return container_get(&fonts_main, sel-3);
 }
 
 #define FLAG_PART(start, count) ((flags >> start) % (1 << count))
@@ -742,6 +796,17 @@ int len(const uint32_t flags, const std::string& t)
     return text_len * pf.scale;
 }
 
+int height(const uint32_t flags)
+{
+    PrintFlags pf = decode_print_flags(flags);
+    if (pf.font_sel == NULL)
+    {
+        return 8;
+    }
+
+    return pf.font_sel->glyph_h * pf.scale;
+}
+
 void print(
     const uint32_t flags,
     int x,
@@ -753,6 +818,10 @@ void print(
 )
 {
     PrintFlags pf = decode_print_flags(flags);
+    if (pf.font_sel == NULL)
+    {
+        return;
+    }
 
     if (pf.align_cen || pf.align_right)
     {