From 087c6695bbdd9d7da181dd129b88d92794a917cc Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Wed, 20 Oct 2021 15:40:06 +0200
Subject: [PATCH] Handle having no fonts (missing "default_fonts" feature)
 without a crash

---
 epaint/src/text/font.rs        | 9 ++++++---
 epaint/src/text/text_layout.rs | 6 ++++--
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/epaint/src/text/font.rs b/epaint/src/text/font.rs
index bac9401f..4037a0a3 100644
--- a/epaint/src/text/font.rs
+++ b/epaint/src/text/font.rs
@@ -215,7 +215,7 @@ impl Font {
                 fonts,
                 characters: RwLock::new(None),
                 replacement_glyph: Default::default(),
-                pixels_per_point: 0.0,
+                pixels_per_point: 1.0,
                 row_height: 0.0,
                 glyph_info_cache: Default::default(),
             };
@@ -318,10 +318,13 @@ impl Font {
     }
 
     #[inline]
-    pub(crate) fn glyph_info_and_font_impl(&self, c: char) -> (&FontImpl, GlyphInfo) {
+    pub(crate) fn glyph_info_and_font_impl(&self, c: char) -> (Option<&FontImpl>, GlyphInfo) {
+        if self.fonts.is_empty() {
+            return (None, self.replacement_glyph.1);
+        }
         let (font_index, glyph_info) = self.glyph_info(c);
         let font_impl = &self.fonts[font_index];
-        (font_impl, glyph_info)
+        (Some(font_impl), glyph_info)
     }
 
     fn glyph_info_no_cache_or_fallback(&self, c: char) -> Option<(FontIndex, GlyphInfo)> {
diff --git a/epaint/src/text/text_layout.rs b/epaint/src/text/text_layout.rs
index 994440d1..bdcb1eef 100644
--- a/epaint/src/text/text_layout.rs
+++ b/epaint/src/text/text_layout.rs
@@ -72,8 +72,10 @@ fn layout_section(
             paragraph.empty_paragraph_height = font_height; // TODO: replace this hack with actually including `\n` in the glyphs?
         } else {
             let (font_impl, glyph_info) = font.glyph_info_and_font_impl(chr);
-            if let Some(last_glyph_id) = last_glyph_id {
-                paragraph.cursor_x += font_impl.pair_kerning(last_glyph_id, glyph_info.id)
+            if let Some(font_impl) = font_impl {
+                if let Some(last_glyph_id) = last_glyph_id {
+                    paragraph.cursor_x += font_impl.pair_kerning(last_glyph_id, glyph_info.id)
+                }
             }
 
             paragraph.glyphs.push(Glyph {