Running tour example crashes

[cassc]

$ RUST_BACKTRACE=full cargo run --example tour
   Compiling iced v0.1.0-alpha.1 (/opt/user/projects/rust/iced)
    Finished dev [unoptimized + debuginfo] target(s) in 8.73s
     Running `target/debug/examples/tour`
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', src/libcore/option.rs:378:21
stack backtrace:
   0:     0x55788f0bf524 - backtrace::backtrace::libunwind::trace::h924a2d8576118736
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.37/src/backtrace/libunwind.rs:88
   1:     0x55788f0bf524 - backtrace::backtrace::trace_unsynchronized::h74a88d3cf8e9a73f
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.37/src/backtrace/mod.rs:66
   2:     0x55788f0bf524 - std::sys_common::backtrace::_print_fmt::hd0a3b38a8cacdd34
                               at src/libstd/sys_common/backtrace.rs:77
   3:     0x55788f0bf524 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h900e23881de8b515
                               at src/libstd/sys_common/backtrace.rs:61
   4:     0x55788f0e18fc - core::fmt::write::hb62ff58e7d34938d
                               at src/libcore/fmt/mod.rs:1028
   5:     0x55788f0bc6c7 - std::io::Write::write_fmt::h1145a99f1b56dffb
                               at src/libstd/io/mod.rs:1412
   6:     0x55788f0c1a5e - std::sys_common::backtrace::_print::h07f05d3309624875
                               at src/libstd/sys_common/backtrace.rs:65
   7:     0x55788f0c1a5e - std::sys_common::backtrace::print::hb74628deb996392c
                               at src/libstd/sys_common/backtrace.rs:50
   8:     0x55788f0c1a5e - std::panicking::default_hook::{{closure}}::h734c09947ffbd003
                               at src/libstd/panicking.rs:188
   9:     0x55788f0c1761 - std::panicking::default_hook::h908a92137d0058d0
                               at src/libstd/panicking.rs:205
  10:     0x55788f0c2155 - std::panicking::rust_panic_with_hook::h650d4fa2f01dd14f
                               at src/libstd/panicking.rs:468
  11:     0x55788f0c1cf2 - std::panicking::continue_panic_fmt::h5a2e12ad03a05116
                               at src/libstd/panicking.rs:375
  12:     0x55788f0c1be6 - rust_begin_unwind
                               at src/libstd/panicking.rs:302
  13:     0x55788f0dd84a - core::panicking::panic_fmt::h2085bf231b704859
                               at src/libcore/panicking.rs:84
  14:     0x55788f0dd789 - core::panicking::panic::h661d298fb9656deb
                               at src/libcore/panicking.rs:49
  15:     0x55788ed50bb8 - core::option::Option<T>::unwrap::h696c273354b9d247
                               at /rustc/d6e4028a0db6b13d9a603baad109d6c902802c03/src/libcore/macros.rs:12
  16:     0x55788ee4fb4a - wgpu_request_adapter
                               at /home/user/.cargo/registry/src/mirrors.ustc.edu.cn-61ef6e0cd06fb9b8/wgpu-native-0.4.0/src/instance.rs:474
  17:     0x55788ec33a2e - wgpu::Adapter::request::h27ad7906023de13e
                               at /home/user/.cargo/registry/src/mirrors.ustc.edu.cn-61ef6e0cd06fb9b8/wgpu-0.4.0/src/lib.rs:545
  18:     0x55788e8a7a49 - iced_wgpu::renderer::Renderer::new::hd64e44c0cfaceb9b
                               at wgpu/src/renderer.rs:52
  19:     0x55788e8a95fd - <iced_wgpu::renderer::Renderer as iced_native::renderer::windowed::Windowed>::new::h1187b1c0a75e7ebf
                               at wgpu/src/renderer.rs:408
  20:     0x55788e2b1ad4 - iced_winit::application::Application::run::h9e52d075590b103d
                               at /opt/user/projects/rust/iced/winit/src/application.rs:45
  21:     0x55788e30524f - iced::Application::run::hc8dd05cc18aeb769
                               at /opt/user/projects/rust/iced/src/lib.rs:19
  22:     0x55788e27902e - tour::main::h631a4a9956d12f72
                               at examples/tour.rs:12
  23:     0x55788e29a320 - std::rt::lang_start::{{closure}}::hde72aaacb5a38ea1
                               at /rustc/d6e4028a0db6b13d9a603baad109d6c902802c03/src/libstd/rt.rs:61
  24:     0x55788f0c1b83 - std::rt::lang_start_internal::{{closure}}::hcf6da9c99990640b
                               at src/libstd/rt.rs:48
  25:     0x55788f0c1b83 - std::panicking::try::do_call::h17432816cf89d4ed
                               at src/libstd/panicking.rs:287
  26:     0x55788f0c5f9a - __rust_maybe_catch_panic
                               at src/libpanic_unwind/lib.rs:80
  27:     0x55788f0c270d - std::panicking::try::h0e688f45fe70b693
                               at src/libstd/panicking.rs:265
  28:     0x55788f0c270d - std::panic::catch_unwind::hbb42d3798dc91a2f
                               at src/libstd/panic.rs:396
  29:     0x55788f0c270d - std::rt::lang_start_internal::h4acffefca599d770
                               at src/libstd/rt.rs:47
  30:     0x55788e29a2f9 - std::rt::lang_start::h14dfe4dc38d8df1b
                               at /rustc/d6e4028a0db6b13d9a603baad109d6c902802c03/src/libstd/rt.rs:61
  31:     0x55788e27f13a - main
  32:     0x7f8b6f1ca153 - __libc_start_main
  33:     0x55788e2691ae - _start
  34:                0x0 - <unknown>

[hecrj]

Thanks for the report!

The panic is most likely caused by a lack of compatible graphics adapters. The unhelpful error message is a wgpu issue: gfx-rs/wgpu#368

Could you share more details about your environment? If you are on Linux, ensure you have Vulkan drivers installed (you may also need Vulkan utilities).

[cassc]

Than you!

I am using Arch Linux. I installed Vulkan following ArchWiki . Now the example runs successfully, but all the texts are displayed as squares.

[cassc]

After changing this line https://github.com/hecrj/iced/blob/b31a80f2c0ca198f1bf0206618654415d2da460e/wgpu/src/renderer.rs#L68 to some font title I found using fc-list and now text shows correctly.

.load(&[font::Family::Title("方正华隶简体".to_string()), font::Family::Serif])

Thank you!

[hecrj]

Now the example runs successfully, but all the texts are displayed as squares.

This is a hard problem to solve. It is part of the roadmap (see #33).

The author of skribo did some interesting research that may be useful once we decide to tackle this: https://github.com/linebender/skribo/blob/master/docs/script_matching.md