Fallback to embedded font when system font fails

wgpu/Cargo.toml

@@ -4,14 +4,14 @@ version = "0.1.0"
 authors = ["Héctor Ramón Jiménez <hector0193@gmail.com>"]
 edition = "2018"
 description = "A wgpu renderer for Iced"
-license = "MIT"
+license = "MIT AND OFL-1.1"
 repository = "https://github.com/hecrj/iced"
 
 [dependencies]
 iced_native = { version = "0.1.0", path = "../native" }
 wgpu = "0.4"
 glyph_brush = "0.6"
-wgpu_glyph = "0.6"
+wgpu_glyph = { version = "0.7", git = "https://github.com/hecrj/wgpu_glyph", branch = "fix/font-load-panic" }
 raw-window-handle = "0.3"
 image = "0.22"
 glam = "0.8"

wgpu/fonts/OFL.txt

@@ -0,0 +1,93 @@
+Copyright (c) 2010-2014 by tyPoland Lukasz Dziedzic (team@latofonts.com) with Reserved Font Name "Lato"
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

wgpu/src/text.rs

@@ -11,6 +11,8 @@ pub const BUILTIN_ICONS: iced_native::Font = iced_native::Font::External {
 
 pub const CHECKMARK_ICON: char = '\u{F00C}';
 
+const FALLBACK_FONT: &[u8] = include_bytes!("../fonts/Lato-Regular.ttf");
+
 #[derive(Debug)]
 pub struct Pipeline {
     draw_brush: RefCell<wgpu_glyph::GlyphBrush<'static, ()>>,
@@ -26,24 +28,36 @@ impl Pipeline {
 
         let default_font = font_source
             .load(&[font::Family::SansSerif, font::Family::Serif])
-            .expect("Find sans-serif or serif font");
+            .unwrap_or_else(|_| FALLBACK_FONT.to_vec());
 
         let mono_font = font_source
             .load(&[font::Family::Monospace])
-            .expect("Find monospace font");
+            .unwrap_or_else(|_| FALLBACK_FONT.to_vec());
 
-        let draw_brush =
+        let load_glyph_brush = |font: Vec<u8>| {
+            let builder =
                 wgpu_glyph::GlyphBrushBuilder::using_fonts_bytes(vec![
-                mono_font,
+                    mono_font.clone(),
-                default_font.clone(),
+                    font.clone(),
-            ])
+                ])?;
+
+            Ok((
+                builder,
+                glyph_brush::GlyphBrushBuilder::using_font_bytes(font).build(),
+            ))
+        };
+
+        let (brush_builder, measure_brush) = load_glyph_brush(default_font)
+            .unwrap_or_else(|_: wgpu_glyph::rusttype::Error| {
+                log::warn!("System font failed to load. Falling back to embedded font...");
+
+                load_glyph_brush(FALLBACK_FONT.to_vec()).expect("Load fallback font")
+            });
+
+        let draw_brush = brush_builder
             .initial_cache_size((2048, 2048))
             .build(device, wgpu::TextureFormat::Bgra8UnormSrgb);
 
-        let measure_brush =
-            glyph_brush::GlyphBrushBuilder::using_font_bytes(default_font)
-                .build();
-
         Pipeline {
             draw_brush: RefCell::new(draw_brush),
             draw_font_map: RefCell::new(HashMap::new()),