From 4e8341d35c20a8447ac948d6c84cae5ab098bac2 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Wed, 14 Dec 2022 15:15:29 +0100
Subject: [PATCH] Don't render the \r (Carriage Return) character, because it
 sucks (#2452)

* Don't render the \r (Carriage Return) character, because it sucks

* Update PR links

* Fix doclink
---
 CHANGELOG.md                   |  1 +
 crates/epaint/CHANGELOG.md     |  3 ++-
 crates/epaint/src/text/font.rs | 31 +++++++++++++++++++++----------
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4e5c8c1e..d65ce7a7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ NOTE: [`epaint`](crates/epaint/CHANGELOG.md), [`eframe`](crates/eframe/CHANGELOG
 
 ### Fixed 🐛
 * Expose `TextEdit`'s multiline flag to AccessKit ([#2448](https://github.com/emilk/egui/pull/2448)).
+* Don't render `\r` (Carriage Return) ([#2452](https://github.com/emilk/egui/pull/2452)).
 
 
 ## 0.20.1 - 2022-12-11 - Fix key-repeat
diff --git a/crates/epaint/CHANGELOG.md b/crates/epaint/CHANGELOG.md
index 52ac1405..69e2b034 100644
--- a/crates/epaint/CHANGELOG.md
+++ b/crates/epaint/CHANGELOG.md
@@ -4,6 +4,7 @@ All notable changes to the epaint crate will be documented in this file.
 
 ## Unreleased
 * Improve the look of thin white lines ([#2437](https://github.com/emilk/egui/pull/2437)).
+* Don't render `\r` (Carriage Return) ([#2452](https://github.com/emilk/egui/pull/2452)).
 
 
 ## 0.20.0 - 2022-12-08
@@ -20,7 +21,7 @@ All notable changes to the epaint crate will be documented in this file.
 * Added `epaint::hex_color!` to create `Color32`'s from hex strings under the `color-hex` feature ([#1596](https://github.com/emilk/egui/pull/1596)).
 * Optimize tessellation of filled circles by 10x or more ([#1616](https://github.com/emilk/egui/pull/1616)).
 * Added opt-in feature `deadlock_detection` to detect double-lock of mutexes on the same thread ([#1619](https://github.com/emilk/egui/pull/1619)).
-* Texture loading now takes a `TexureOptions` with minification and magnification filters ([#2224](https://github.com/emilk/egui/pull/2224)).
+* Texture loading now takes a `TextureOptions` with minification and magnification filters ([#2224](https://github.com/emilk/egui/pull/2224)).
 
 
 ## 0.18.1 - 2022-05-01
diff --git a/crates/epaint/src/text/font.rs b/crates/epaint/src/text/font.rs
index 4fb0079c..67dfd43e 100644
--- a/crates/epaint/src/text/font.rs
+++ b/crates/epaint/src/text/font.rs
@@ -38,11 +38,12 @@ pub struct GlyphInfo {
     /// Unit: points.
     pub advance_width: f32,
 
-    /// Texture coordinates. None for space.
+    /// Texture coordinates.
     pub uv_rect: UvRect,
 }
 
 impl Default for GlyphInfo {
+    /// Basically a zero-width space.
     fn default() -> Self {
         Self {
             id: ab_glyph::GlyphId(0),
@@ -105,6 +106,9 @@ impl FontImpl {
         }
     }
 
+    /// Code points that will always be replaced by the replacement character.
+    ///
+    /// See also [`invisible_char`].
     fn ignore_character(&self, chr: char) -> bool {
         if self.name == "emoji-icon-font" {
             // HACK: https://github.com/emilk/egui/issues/1284 https://github.com/jslegers/emoji-icon-font/issues/18
@@ -142,7 +146,7 @@ impl FontImpl {
         }
 
         if self.ignore_character(c) {
-            return None;
+            return None; // these will result in the replacement character when rendering
         }
 
         if c == '\t' {
@@ -173,19 +177,18 @@ impl FontImpl {
             }
         }
 
+        if invisible_char(c) {
+            let glyph_info = GlyphInfo::default();
+            self.glyph_info_cache.write().insert(c, glyph_info);
+            return Some(glyph_info);
+        }
+
         // Add new character:
         use ab_glyph::Font as _;
         let glyph_id = self.ab_glyph_font.glyph_id(c);
 
         if glyph_id.0 == 0 {
-            if invisible_char(c) {
-                // hack
-                let glyph_info = GlyphInfo::default();
-                self.glyph_info_cache.write().insert(c, glyph_info);
-                Some(glyph_info)
-            } else {
-                None // unsupported character
-            }
+            None // unsupported character
         } else {
             let glyph_info = allocate_glyph(
                 &mut self.atlas.lock(),
@@ -376,8 +379,16 @@ impl Font {
     }
 }
 
+/// Code points that will always be invisible (zero width).
+///
+/// See also [`FontImpl::ignore_character`].
 #[inline]
 fn invisible_char(c: char) -> bool {
+    if c == '\r' {
+        // A character most vile and pernicious. Don't display it.
+        return true;
+    }
+
     // See https://github.com/emilk/egui/issues/336
 
     // From https://www.fileformat.info/info/unicode/category/Cf/list.htm