(svn r11646) -Codechange: check whether (some) characters are missing in the current 'font' for the 'currently' chosen language and give a warning when that does happen.

src/openttd.cpp

@@ -342,6 +342,8 @@ static void LoadIntroGame()
 	_cursor.fix_at = false;
 	MarkWholeScreenDirty();
 
+	CheckForMissingGlyphsInLoadedLanguagePack();
+
 	/* Play main theme */
 	if (_music_driver->IsSongPlaying()) ResetMusic();
 }

src/settings_gui.cpp

@@ -255,6 +255,7 @@ static void GameOptionsWndProc(Window *w, WindowEvent *e)
 			break;
 		case 24: /* Change interface language */
 			ReadLanguagePack(e->we.dropdown.index);
+			CheckForMissingGlyphsInLoadedLanguagePack();
 			UpdateAllStationVirtCoord();
 			MarkWholeScreenDirty();
 			break;

src/strings.cpp

@@ -32,6 +32,8 @@
 #include "signs.h"
 #include "vehicle.h"
 #include "newgrf_engine.h"
+#include "fontcache.h"
+#include "gui.h"
 
 /* for opendir/readdir/closedir */
 # include "fios.h"
@@ -1435,3 +1437,55 @@ void InitializeLanguagePacks()
 
 	if (!ReadLanguagePack(chosen_language)) error("Can't read language pack '%s'", dl->ent[chosen_language].file);
 }
+
+/**
+ * Check whether the currently loaded language pack
+ * uses characters that the currently loaded font
+ * does not support. If this is the case an error
+ * message will be shown in English. The error
+ * message will not be localized because that would
+ * mean it might use characters that are not in the
+ * font, which is the whole reason this check has
+ * been added.
+ */
+void CheckForMissingGlyphsInLoadedLanguagePack()
+{
+	for (uint i = 0; i != 32; i++) {
+		for (uint j = 0; j < _langtab_num[i]; j++) {
+			const char *string = _langpack_offs[_langtab_start[i] + j];
+			WChar c;
+			while ((c = Utf8Consume(&string)) != '\0') {
+				if (c == SCC_SETX) {
+					/*
+					 * SetX is, together with SetXY as special character that
+					 * uses the next (two) characters as data points. We have
+					 * to skip those, otherwise the UTF8 reading will go
+					 * haywire.
+					 */
+					string++;
+				} else if (c == SCC_SETXY) {
+					string += 2;
+				} else if (IsPrintable(c) && GetUnicodeGlyph(FS_NORMAL, c) == 0) {
+					/*
+					 * The character is printable, but not in the normal font.
+					 * This is the case we were testing for. In this case we
+					 * have to show the error. As we do not want the string to
+					 * be translated by the translators, we 'force' it into the
+					 * binary and 'load' it via a BindCString. To do this
+					 * properly we have to set the color of the string,
+					 * otherwise we end up with a lot of artefacts. The color
+					 * 'character' might change in the future, so for safety
+					 * we just Utf8 Encode it into the string, which takes
+					 * exactly three characters, so it replaces the "XXX" with
+					 * the color marker.
+					 */
+					static char *err_str = strdup("XXXThe current font misses characters used in the strings for this language. Read the readme to see how to solve this.");
+					Utf8Encode(err_str, SCC_YELLOW);
+					StringID err_msg = BindCString(err_str);
+					ShowErrorMessage(INVALID_STRING_ID, err_msg, 0, 0);
+					return;
+				}
+			}
+		}
+	}
+}

src/strings.h

@@ -83,4 +83,6 @@ void InitializeLanguagePacks();
 
 int CDECL StringIDSorter(const void *a, const void *b);
 
+void CheckForMissingGlyphsInLoadedLanguagePack();
+
 #endif /* STRINGS_H */