Limit scaling for Arthur to prevent Arthur corrupting itself

Win/FrotzApp.cpp

@@ -534,6 +534,15 @@ void FrotzApp::CreateMainWindow(void)
     int scale = (scaleX > scaleY) ? scaleY : scaleX;
     if (scale < 1)
       scale = 1;
+    if ((story_id == ARTHUR) && (scale > 1))
+    {
+      // Arthur corrupts its internal state if the screen is too wide
+      int cw = theWnd->GetCharWidth('0');
+      if (320*scale > 140*cw)
+        scale = (cw*140)/320;
+      if (scale < 1)
+        scale = 1;
+    }
     int width = (320*scale)+borderX;
     int height = (200*scale)+borderY;
 

Win/help/revision.htm

@@ -8,11 +8,14 @@ <h1>Revision History</h1>
 
 <b>1.22</b>
 <ul>
-<li>The <b>print_table</b> opcode now interprets the string passed to it as ZSCII,
-rather than ASCII.
+<li>There is a flaw in the Infocom game Arthur: if the screen is too wide, then the
+game corrupts its internal state. As a result, Frotz tries to limit the initial size
+of its window when running Arthur to prevent this.
 <li>Font substitution, which attempts to find font characters in other fonts when the
 characters are not in the current font, has been turned off for fixed-width fonts, as
 it caused more problems than it solved.
+<li>The <b>print_table</b> opcode now interprets the string passed to it as ZSCII,
+rather than ASCII.
 </ul>
 
 <b>1.21</b>