A basic wasm backend is added as a continuation of linebender#30.
Since std::time isn't available on wasm, an additional dependency is
added to abstract std::time::Instant to work with wasm.

This commit ensures that all examples run with minimal changes.
More specifically we don't need to remove the .use_simple_logger() call
on all Apps.

The resize callback should be registered to the window, since resizing
the window doesn't call the resize callback for canvases even if those
do get resized.

The scroll example now works as expected on hi and low dpi screens.

This makes passing it easier to pass owned strings when creating a new
KeyEvent, which is necessary when interfacing with WASM.

This should be the default behavior to make text widgets usable.
At a later iteration it may be better to only disable the browser from
going back when a widget is selected that is expecting keyboard input
where backspace is intended for something else.

I expect this functionality would require some way of accessing the
web_sys event from within a druid callback.

This commit addresses comments in the code review:

Key text:
  - web_sys returns the name of each pressed key from which we can
    generate a viable printable string. This mechanism is revised to
    include all non-printable keys as listed in MDN.
  - notably, the tab character and numpad characters have gained
    printable text in this commit.

console_log:
  - console_log is not required in wasm builds.
  - integrated console_log with the use_simple_logger api. `console_log`
    is initialized with log level `trace` as is done in simple logger by
    default.

Style:
  - non std use statements are now before third party use statements.
  - key_to_text function signature refactor
  - specify the log module when calling log::{warn, error} explicitly.

Moved console_log dependency from druid-shell to druid, since this is
where it is initialized. This fixes the wasm build.

This commit creates a symlink to the examples directory on demand.

This allows the wasm examples to build even when the target arch is not
wasm32.

This addresses the CI failures caused by the weird build of the wasm
examples.

To elaborate:
In order to include each of the examples in the wasm example, a
symlink to the examples directory is created in build.rs along with the
corresponding examples.rs module which declares examples known to work
with wasm. To satisfy CI, the examples.rs committed to the repo must be
empty since rustfmt does not call "build.rs".

The included .gitignore ignores the generated examples module. The
examples.rs should remain committed, but it need not be ever changed.

The newly introduced lifetime parameter must be specified exmplicitly.

wasm targets cannot be run in the normal way.

The tests cannot be run in the normal way anyways. Leaving this for a
future PR to flush out.

This commit exposes the error of the missing implementation for file dialogs in the web backend using log::warn. This is a temporary solution until the `open_file_sync` and `save_as_sync` functions propagate the error downstream using Result instead of Option.

Co-Authored-By: Leopold Luley <[email protected]>

Co-Authored-By: Leopold Luley <[email protected]>

Co-Authored-By: Leopold Luley <[email protected]>

The types in that module have since made their way into druid itself.

This is most likely not needed.

This commit attempts a different approach at including the automatically
generated examples from the parent directory.
This method satisfies both rustfmt and cargo test as before, but it also
doesn't modify any files in the source tree, keeping the diff clean
after a build.

This commit fixes the generated html file for the switch example to load
"switch_demo" instead of "switch" for the switch example. The word
switch conflicts with JavaScript's switch statement, which is the reason
for this awkwardness.