Spit crosshair and labels API

[michalsustr]

Now you can have one without the other. Addresses #217

Public API changes

The PlotItem label formatter is now optional:

-pub fn egui_plot::PlotItem::on_hover(&self, plot_area_response: &egui::response::Response, elem: egui_plot::ClosestElem, shapes: &mut alloc::vec::Vec<epaint::shapes::shape::Shape>, cursors: &mut alloc::vec::Vec<egui_plot::Cursor>, plot: &egui_plot::PlotConfig<'_>, label_formatter: &egui_plot::LabelFormatter<'_>)
+pub fn egui_plot::PlotItem::on_hover(&self, plot_area_response: &egui::response::Response, elem: egui_plot::ClosestElem, shapes: &mut alloc::vec::Vec<epaint::shapes::shape::Shape>, cursors: &mut alloc::vec::Vec<egui_plot::Cursor>, plot: &egui_plot::PlotConfig<'_>, label_formatter: &core::option::Option<egui_plot::LabelFormatter<'_>>)

Allow to specify crosshair:

+pub fn egui_plot::Plot<'a>::show_crosshair(self, show: bool) -> Self
+pub egui_plot::PlotConfig::show_crosshair: bool

Add default formatter:

+pub fn egui_plot::default_label_formatter(name: &str, value: &egui_plot::PlotPoint) -> alloc::string::String

And by default, labels are not shown. You have to enable it by passing label_formatter(you_label_formatter)
You can use the default_label_formatter.

[github-actions]

View snapshot changes at kitdiff