From e523a38bd2665a1a487382c5042d94770e4087af Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Mon, 6 Dec 2021 04:32:24 -0500
Subject: better (i think?) handling of weird character widths

control codes are ignored completely, and everything else defaults to 1
instead of 0
---
 CHANGELOG.md                  | 16 ++++++++++++++--
 src/cell.rs                   |  2 +-
 src/screen.rs                 |  7 ++++++-
 tests/data/fixtures/ri/5.json |  4 ++--
 tests/data/fixtures/ri/6.json |  4 ++--
 5 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 69c9708..3538ba3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,15 +1,27 @@
 # Changelog
 
+## [Unreleased]
+
+### Changed
+
+* Unknown UTF-8 characters default to a width of 1, rather than 0 (except for
+  control characters, as mentioned below)
+
+### Fixed
+
+* Ignore C1 control characters rather than adding them to the cell data, since
+  they are non-printable
+
 ## [0.13.2] - 2021-12-05
 
-## Changed
+### Changed
 
 * Delay allocation of the alternate screen until it is used (saves a bit of
   memory in basic cases)
 
 ## [0.13.1] - 2021-12-04
 
-## Fixed
+### Fixed
 
 * Fixed various line wrapping state issues
 * Fixed cursor positioning after writing zero width characters at the end of
diff --git a/src/cell.rs b/src/cell.rs
index 7262c8d..857c9e2 100644
--- a/src/cell.rs
+++ b/src/cell.rs
@@ -36,7 +36,7 @@ impl Cell {
         // strings in this context should always be an arbitrary character
         // followed by zero or more zero-width characters, so we should only
         // have to look at the first character
-        self.set_wide(c.width().unwrap_or(0) > 1);
+        self.set_wide(c.width().unwrap_or(1) > 1);
         self.attrs = a;
     }
 
diff --git a/src/screen.rs b/src/screen.rs
index ae6bd2d..558c41f 100644
--- a/src/screen.rs
+++ b/src/screen.rs
@@ -820,7 +820,12 @@ impl Screen {
         let size = self.grid().size();
         let attrs = self.attrs;
 
-        let width = c.width().unwrap_or(0).try_into().unwrap();
+        let width = c.width();
+        if width.is_none() && (c as u32) < 256 {
+            // don't even try to draw control characters
+            return;
+        }
+        let width = width.unwrap_or(1).try_into().unwrap();
 
         // it doesn't make any sense to wrap if the last column in a row
         // didn't already have contents. don't try to handle the case where a
diff --git a/tests/data/fixtures/ri/5.json b/tests/data/fixtures/ri/5.json
index e70e9fa..c4852e2 100644
--- a/tests/data/fixtures/ri/5.json
+++ b/tests/data/fixtures/ri/5.json
@@ -1,8 +1,8 @@
 {
-  "contents": "                                                                               a\n\nb",
+  "contents": "                                                                               a\n\nb",
   "cells": {
     "0,79": {
-      "contents": "a"
+      "contents": "a"
     },
     "2,0": {
       "contents": "b"
diff --git a/tests/data/fixtures/ri/6.json b/tests/data/fixtures/ri/6.json
index b58e830..7bf46db 100644
--- a/tests/data/fixtures/ri/6.json
+++ b/tests/data/fixtures/ri/6.json
@@ -1,8 +1,8 @@
 {
-  "contents": "\n                                                                               a\n\nb",
+  "contents": "\n                                                                               a\n\nb",
   "cells": {
     "1,79": {
-      "contents": "a"
+      "contents": "a"
     },
     "3,0": {
       "contents": "b"
-- 
cgit v1.2.3-54-g00ecf