fix writing of utf8 chars in the last column

Using insch is nice, because it does not update the cursor position, but
it does not work with utf8 chars and outputs garbage instead.

The problem can be avoided by using addch, but it creates a new problem:
addch moves the cursor. For all but the very last character on the
screen that's fine, but adding the last character on the screen means
scrolling. Thus we follow the advice from
http://stackoverflow.com/a/41923640/1626632 and disable scrolling and
catching the exception.

1 files changed, 10 insertions, 1 deletions

diff --git a/tcvt.py b/tcvt.py
index 64c2ff5..e97da3c 100755
--- a/tcvt.py
+++ b/tcvt.py
@@ -168,11 +168,20 @@ class Columns:
 
     def addch(self, char):
         if self.xpos == self.columnwidth - 1:
-            self.curwin.insch(self.curypos, self.curxpos, char, self.attrs)
             if self.ypos + 1 == self.numcolumns * self.height:
+                self.curwin.scrollok(0)  # disable scrolling for the addch call
+                try:
+                    self.curwin.addch(self.curypos, self.curxpos, char,
+                                      self.attrs)
+                except curses.error:
+                    # It errors out, but still draws the character.
+                    # http://stackoverflow.com/a/41923640/1626632
+                    pass
+                self.curwin.scrollok(1)
                 self.scroll()
                 self.move(self.ypos, 0)
             else:
+                self.curwin.addch(self.curypos, self.curxpos, char, self.attrs)
                 self.move(self.ypos + 1, 0)
         else:
             self.curwin.addch(self.curypos, self.curxpos, char, self.attrs)