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Formatter for plot axis labels (#1130)

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* Fix Orientation not exposed, although there are public fields with its type

* Implement formatters for X/Y axis labels

* Use array instead of separate X/Y formatters

* Swap axis formatters if charts are horizontal

* Review suggestions
This commit is contained in:
Jan Haller 2022-01-24 22:34:00 +01:00 committed by GitHub
parent 3418eb5d35
commit 366f544655
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 97 additions and 17 deletions
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2
CHANGELOG.md
View file

@ -16,6 +16,7 @@ NOTE: [`epaint`](epaint/CHANGELOG.md), [`eframe`](eframe/CHANGELOG.md), [`egui_w
* `Context::load_texture` to convert an image into a texture which can be displayed using e.g. `ui.image(texture, size)` ([#1110](https://github.com/emilk/egui/pull/1110)).
* Added `Ui::add_visible` and `Ui::add_visible_ui`.
* Added `CollapsingHeader::icon` to override the default open/close icon using a custom function. ([1147](https://github.com/emilk/egui/pull/1147))
* Added `Plot::x_axis_formatter` and `Plot::y_axis_formatter` for custom axis labels ([#1130](https://github.com/emilk/egui/pull/1130))
### Changed 🔧
* ⚠️ `Context::input` and `Ui::input` now locks a mutex. This can lead to a dead-lock is used in an `if let` binding!
@ -36,6 +37,7 @@ NOTE: [`epaint`](epaint/CHANGELOG.md), [`eframe`](eframe/CHANGELOG.md), [`egui_w
### Fixed 🐛
* Context menu now respects the theme ([#1043](https://github.com/emilk/egui/pull/1043))
* Plot `Orientation` was not public, although fields using this type were ([#1130](https://github.com/emilk/egui/pull/1130))
### Contributors 🙏
* [danielkeller](https://github.com/danielkeller): [#1050](https://github.com/emilk/egui/pull/1050).

4
egui/src/widgets/plot/items/mod.rs
View file

@ -9,11 +9,11 @@ use crate::*;
use super::{CustomLabelFuncRef, PlotBounds, ScreenTransform};
use rect_elem::*;
use values::*;
use values::{ClosestElem, PlotGeometry};
pub use bar::Bar;
pub use box_elem::{BoxElem, BoxSpread};
pub use values::{LineStyle, MarkerShape, Value, Values};
pub use values::{LineStyle, MarkerShape, Orientation, Value, Values};
mod bar;
mod box_elem;

1
egui/src/widgets/plot/items/values.rs
View file

@ -125,6 +125,7 @@ impl ToString for LineStyle {
// ----------------------------------------------------------------------------
/// Determines whether a plot element is vertically or horizontally oriented.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum Orientation {
Horizontal,

56
egui/src/widgets/plot/mod.rs
View file

@ -10,7 +10,7 @@ use transform::{PlotBounds, ScreenTransform};
pub use items::{
Arrows, Bar, BarChart, BoxElem, BoxPlot, BoxSpread, HLine, Line, LineStyle, MarkerShape,
PlotImage, Points, Polygon, Text, VLine, Value, Values,
Orientation, PlotImage, Points, Polygon, Text, VLine, Value, Values,
};
pub use legend::{Corner, Legend};
@ -21,6 +21,9 @@ mod transform;
type CustomLabelFunc = dyn Fn(&str, &Value) -> String;
type CustomLabelFuncRef = Option<Box<CustomLabelFunc>>;
type AxisFormatterFn = dyn Fn(f64) -> String;
type AxisFormatter = Option<Box<AxisFormatterFn>>;
// ----------------------------------------------------------------------------
/// Information about the plot that has to persist between frames.
@ -80,6 +83,7 @@ pub struct Plot {
show_x: bool,
show_y: bool,
custom_label_func: CustomLabelFuncRef,
axis_formatters: [AxisFormatter; 2],
legend_config: Option<Legend>,
show_background: bool,
show_axes: [bool; 2],
@ -107,6 +111,7 @@ impl Plot {
show_x: true,
show_y: true,
custom_label_func: None,
axis_formatters: [None, None], // [None; 2] requires Copy
legend_config: None,
show_background: true,
show_axes: [true; 2],
@ -208,11 +213,35 @@ impl Plot {
/// .show(ui, |plot_ui| plot_ui.line(line));
/// # });
/// ```
pub fn custom_label_func<F: 'static + Fn(&str, &Value) -> String>(
pub fn custom_label_func(
mut self,
custom_lebel_func: F,
custom_label_func: impl Fn(&str, &Value) -> String + 'static,
) -> Self {
self.custom_label_func = Some(Box::new(custom_lebel_func));
self.custom_label_func = Some(Box::new(custom_label_func));
self
}
/// Provide a function to customize the labels for the X axis.
///
/// This is useful for custom input domains, e.g. date/time.
///
/// If axis labels should not appear for certain values or beyond a certain zoom/resolution,
/// the formatter function can return empty strings. This is also useful if your domain is
/// discrete (e.g. only full days in a calendar).
pub fn x_axis_formatter(mut self, func: impl Fn(f64) -> String + 'static) -> Self {
self.axis_formatters[0] = Some(Box::new(func));
self
}
/// Provide a function to customize the labels for the Y axis.
///
/// This is useful for custom value representation, e.g. percentage or units.
///
/// If axis labels should not appear for certain values or beyond a certain zoom/resolution,
/// the formatter function can return empty strings. This is also useful if your Y values are
/// discrete (e.g. only integers).
pub fn y_axis_formatter(mut self, func: impl Fn(f64) -> String + 'static) -> Self {
self.axis_formatters[1] = Some(Box::new(func));
self
}
@ -270,6 +299,7 @@ impl Plot {
mut show_x,
mut show_y,
custom_label_func,
axis_formatters,
legend_config,
show_background,
show_axes,
@ -442,6 +472,7 @@ impl Plot {
show_x,
show_y,
custom_label_func,
axis_formatters,
show_axes,
transform: transform.clone(),
};
@ -650,6 +681,7 @@ struct PreparedPlot {
show_x: bool,
show_y: bool,
custom_label_func: CustomLabelFuncRef,
axis_formatters: [AxisFormatter; 2],
show_axes: [bool; 2],
transform: ScreenTransform,
}
@ -680,7 +712,11 @@ impl PreparedPlot {
}
fn paint_axis(&self, ui: &Ui, axis: usize, shapes: &mut Vec<Shape>) {
let Self { transform, .. } = self;
let Self {
transform,
axis_formatters,
..
} = self;
let bounds = transform.bounds();
@ -740,8 +776,15 @@ impl PreparedPlot {
if text_alpha > 0.0 {
let color = color_from_alpha(ui, text_alpha);
let text = emath::round_to_decimals(value_main, 5).to_string(); // hack
let text: String = if let Some(formatter) = axis_formatters[axis].as_deref() {
formatter(value_main)
} else {
emath::round_to_decimals(value_main, 5).to_string() // hack
};
// Custom formatters can return empty string to signal "no label at this resolution"
if !text.is_empty() {
let galley = ui.painter().layout_no_wrap(text, font_id.clone(), color);
let mut text_pos = pos_in_gui + vec2(1.0, -galley.size().y);
@ -754,6 +797,7 @@ impl PreparedPlot {
shapes.push(Shape::galley(text_pos, galley));
}
}
}
fn color_from_alpha(ui: &Ui, alpha: f32) -> Color32 {
if ui.visuals().dark_mode {

37
egui_demo_lib/src/apps/demo/plot_demo.rs
View file

@ -71,8 +71,8 @@ impl LineDemo {
ui.vertical(|ui| {
ui.style_mut().wrap = Some(false);
ui.checkbox(animate, "animate");
ui.checkbox(square, "square view")
ui.checkbox(animate, "Animate");
ui.checkbox(square, "Square view")
.on_hover_text("Always keep the viewport square.");
ui.checkbox(proportional, "Proportional data axes")
.on_hover_text("Tick are the same size on both axes.");
@ -523,15 +523,40 @@ impl ChartsDemo {
.name("Set 4")
.stack_on(&[&chart1, &chart2, &chart3]);
let mut x_fmt: fn(f64) -> String = |val| {
if val >= 0.0 && val <= 4.0 && is_approx_integer(val) {
// Only label full days from 0 to 4
format!("Day {}", val)
} else {
// Otherwise return empty string (i.e. no label)
String::new()
}
};
let mut y_fmt: fn(f64) -> String = |val| {
let percent = 100.0 * val;
if is_approx_integer(percent) && !is_approx_zero(percent) {
// Only show integer percentages,
// and don't show at Y=0 (label overlaps with X axis label)
format!("{}%", percent)
} else {
String::new()
}
};
if !self.vertical {
chart1 = chart1.horizontal();
chart2 = chart2.horizontal();
chart3 = chart3.horizontal();
chart4 = chart4.horizontal();
std::mem::swap(&mut x_fmt, &mut y_fmt);
}
Plot::new("Stacked Bar Chart Demo")
.legend(Legend::default())
.x_axis_formatter(x_fmt)
.y_axis_formatter(y_fmt)
.data_aspect(1.0)
.show(ui, |plot_ui| {
plot_ui.bar_chart(chart1);
@ -698,3 +723,11 @@ impl super::View for PlotDemo {
}
}
}
fn is_approx_zero(val: f64) -> bool {
val.abs() < 1e-6
}
fn is_approx_integer(val: f64) -> bool {
val.fract().abs() < 1e-6
}