* Part of https://github.com/emilk/egui/issues/1485
This adds a `rayon` feature to `epaint` and `egui` to parallelize
tessellation of large shapes, such as high-resolution plot lines.
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This PR simply allows you to override the opacity of a Galley when you
draw it on screen. Last year I opened #3548 and some changes were
requested to the PR, but unfortunately school got really busy and I
wasn't able to apply them. This PR supersedes #3548 and applys the
changes requested in that PR
Closes#3548
This introduces a special `Color32::PLACEHOLDER` which, during text
painting, will be replaced with `TextShape::fallback_color`.
The fallback color is mandatory to set in all text painting. Usually
this comes from the current visual style.
This lets users color only parts of a `WidgetText` (using e.g. a
`LayoutJob` or a `Galley`), where the uncolored parts (using
`Color32::PLACEHOLDER`) will be replaced by a default widget color (e.g.
blue for a hyperlink).
For instance, you can color the `⚠️`-emoji red in a piece of text red
and leave the rest of the text uncolored. The color of the rest of the
text will then depend on wether or not you put that text in a label, a
button, or a hyperlink.
Overall this simplifies a lot of complexity in the code but comes with a
few breaking changes:
* `TextShape::new`, `Shape::galley`, and `Painter::galley` now take a
fallback color by argument
* `Shape::galley_with_color` has been deprecated (use `Shape::galley`
instead)
* `Painter::galley_with_color` has been deprecated (use
`Painter::galley` instead)
* `WidgetTextGalley` is gone (use `Arc<Galley>` instead)
* `WidgetTextJob` is gone (use `LayoutJob` instead)
* `RichText::into_text_job` has been replaced with
`RichText::into_layout_job`
* `WidgetText::into_text_job` has been replaced with
`WidgetText::into_layout_job`
* Move scroll bar spacing settings to a `struct ScrollSpacing`
* Add a demo for changing scroll bar appearance
* Add setting for ScrollBarVisibility in demo
* Add `#[inline]` to a `ScrollArea` builder methods
* Refactor how scroll bar show/hide is computed
* Add support for floating scroll bars
* Tweak color and opacity of the scroll handle
* Allow allocating a fixed size even for floating scroll bars
* Add three pre-sets of scroll bars: solid, thin, floating
* Use floating scroll bars as the default
* Fix id-clash with bidir scroll areas
* Improve demo
* Fix doclink
* Remove reset button from demo
* Fix doclinks
* Fix visual artifact with thin rounded rectangles
* Fix doclink
* typos
* Imoprove docs for callback shapes
* Improve docs for loader traits
* Use snake_case for feature `all_loaders`
* Make loaders publix
* Slightly better error message on image load failure
* Improve image loading error messages
* Use `bytes://` schema for included bytes loader
* Try user loaders first
* Move `image_loading_spinners` to `Visuals`
* Unify and simplify code
* Make the main text of `Button` optional
This largely makes ImageButton obsolete
* Fix docstrings
* Better docs
* typos
* Use the more explicit `egui_extras::install_image_loaders`
* Simplify `Image::paint_at` function
* Revert "fix all clippy lints and remove them from allow list in cranky (#2419)"
This reverts commit 930ef2db38.
* Explain the cranky lints better
* Add Color32::gamma_multiply
* Remove unused pub use
* Remove non-existing crate category
* Improve color test with more lines
* Improve the look of thin lines, making them look weaker
Before they looked were too strong for the thickness.
* Use asserts for shader compilations
* Update changelogs
