Break out plotting to own crate egui_plot (#3282)

This replaces `egui::plot` with the new crate `egui_plot`

crates/egui_plot/src/items/bar.rs

@@ -0,0 +1,190 @@
+use egui::emath::NumExt;
+use egui::epaint::{Color32, RectShape, Rounding, Shape, Stroke};
+
+use super::{add_rulers_and_text, highlighted_color, Orientation, PlotConfig, RectElement};
+use crate::{BarChart, Cursor, PlotPoint, PlotTransform};
+
+/// One bar in a [`BarChart`]. Potentially floating, allowing stacked bar charts.
+/// Width can be changed to allow variable-width histograms.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Bar {
+    /// Name of plot element in the diagram (annotated by default formatter)
+    pub name: String,
+
+    /// Which direction the bar faces in the diagram
+    pub orientation: Orientation,
+
+    /// Position on the argument (input) axis -- X if vertical, Y if horizontal
+    pub argument: f64,
+
+    /// Position on the value (output) axis -- Y if vertical, X if horizontal
+    pub value: f64,
+
+    /// For stacked bars, this denotes where the bar starts. None if base axis
+    pub base_offset: Option<f64>,
+
+    /// Thickness of the bar
+    pub bar_width: f64,
+
+    /// Line width and color
+    pub stroke: Stroke,
+
+    /// Fill color
+    pub fill: Color32,
+}
+
+impl Bar {
+    /// Create a bar. Its `orientation` is set by its [`BarChart`] parent.
+    ///
+    /// - `argument`: Position on the argument axis (X if vertical, Y if horizontal).
+    /// - `value`: Height of the bar (if vertical).
+    ///
+    /// By default the bar is vertical and its base is at zero.
+    pub fn new(argument: f64, height: f64) -> Bar {
+        Bar {
+            argument,
+            value: height,
+            orientation: Orientation::default(),
+            name: Default::default(),
+            base_offset: None,
+            bar_width: 0.5,
+            stroke: Stroke::new(1.0, Color32::TRANSPARENT),
+            fill: Color32::TRANSPARENT,
+        }
+    }
+
+    /// Name of this bar chart element.
+    #[allow(clippy::needless_pass_by_value)]
+    pub fn name(mut self, name: impl ToString) -> Self {
+        self.name = name.to_string();
+        self
+    }
+
+    /// Add a custom stroke.
+    pub fn stroke(mut self, stroke: impl Into<Stroke>) -> Self {
+        self.stroke = stroke.into();
+        self
+    }
+
+    /// Add a custom fill color.
+    pub fn fill(mut self, color: impl Into<Color32>) -> Self {
+        self.fill = color.into();
+        self
+    }
+
+    /// Offset the base of the bar.
+    /// This offset is on the Y axis for a vertical bar
+    /// and on the X axis for a horizontal bar.
+    pub fn base_offset(mut self, offset: f64) -> Self {
+        self.base_offset = Some(offset);
+        self
+    }
+
+    /// Set the bar width.
+    pub fn width(mut self, width: f64) -> Self {
+        self.bar_width = width;
+        self
+    }
+
+    /// Set orientation of the element as vertical. Argument axis is X.
+    pub fn vertical(mut self) -> Self {
+        self.orientation = Orientation::Vertical;
+        self
+    }
+
+    /// Set orientation of the element as horizontal. Argument axis is Y.
+    pub fn horizontal(mut self) -> Self {
+        self.orientation = Orientation::Horizontal;
+        self
+    }
+
+    pub(super) fn lower(&self) -> f64 {
+        if self.value.is_sign_positive() {
+            self.base_offset.unwrap_or(0.0)
+        } else {
+            self.base_offset.map_or(self.value, |o| o + self.value)
+        }
+    }
+
+    pub(super) fn upper(&self) -> f64 {
+        if self.value.is_sign_positive() {
+            self.base_offset.map_or(self.value, |o| o + self.value)
+        } else {
+            self.base_offset.unwrap_or(0.0)
+        }
+    }
+
+    pub(super) fn add_shapes(
+        &self,
+        transform: &PlotTransform,
+        highlighted: bool,
+        shapes: &mut Vec<Shape>,
+    ) {
+        let (stroke, fill) = if highlighted {
+            highlighted_color(self.stroke, self.fill)
+        } else {
+            (self.stroke, self.fill)
+        };
+
+        let rect = transform.rect_from_values(&self.bounds_min(), &self.bounds_max());
+        let rect = Shape::Rect(RectShape::new(rect, Rounding::ZERO, fill, stroke));
+
+        shapes.push(rect);
+    }
+
+    pub(super) fn add_rulers_and_text(
+        &self,
+        parent: &BarChart,
+        plot: &PlotConfig<'_>,
+        shapes: &mut Vec<Shape>,
+        cursors: &mut Vec<Cursor>,
+    ) {
+        let text: Option<String> = parent
+            .element_formatter
+            .as_ref()
+            .map(|fmt| fmt(self, parent));
+
+        add_rulers_and_text(self, plot, text, shapes, cursors);
+    }
+}
+
+impl RectElement for Bar {
+    fn name(&self) -> &str {
+        self.name.as_str()
+    }
+
+    fn bounds_min(&self) -> PlotPoint {
+        self.point_at(self.argument - self.bar_width / 2.0, self.lower())
+    }
+
+    fn bounds_max(&self) -> PlotPoint {
+        self.point_at(self.argument + self.bar_width / 2.0, self.upper())
+    }
+
+    fn values_with_ruler(&self) -> Vec<PlotPoint> {
+        let base = self.base_offset.unwrap_or(0.0);
+        let value_center = self.point_at(self.argument, base + self.value);
+
+        let mut ruler_positions = vec![value_center];
+
+        if let Some(offset) = self.base_offset {
+            ruler_positions.push(self.point_at(self.argument, offset));
+        }
+
+        ruler_positions
+    }
+
+    fn orientation(&self) -> Orientation {
+        self.orientation
+    }
+
+    fn default_values_format(&self, transform: &PlotTransform) -> String {
+        let scale = transform.dvalue_dpos();
+        let scale = match self.orientation {
+            Orientation::Horizontal => scale[0],
+            Orientation::Vertical => scale[1],
+        };
+        let decimals = ((-scale.abs().log10()).ceil().at_least(0.0) as usize).at_most(6);
+        crate::format_number(self.value, decimals)
+    }
+}