Added stem plots and legend entry hover checking

.gitignore

@@ -1,6 +1,9 @@
 # Generated by Cargo
 # will have compiled files and executables
-/target/
+**/target/
+
+# Editor temporary files
+**/*.swp
 
 # Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
 # More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html

README.md

@@ -83,7 +83,7 @@ created for 64-bit floats.
   - [x] Styling variables
   - [x] Colormaps
   - [x] Legend locations
-- [ ] Plot querying 
+- [x] Plot querying 
   - [x] is hovered
   - [x] mouse position in plot
   - [x] plot limits
@@ -91,7 +91,7 @@ created for 64-bit floats.
   - [x] get plot query
   - [x] are axes hovered
   - [x] Choice of y axis
-  - [ ] Are legend entries hovered
+  - [x] Are legend entries hovered
 - [ ] Utils
   - [x] Plot limit setting
   - [x] imgui-rs style safe push/pop stacks

implot-examples/examples-shared/src/lib.rs

@@ -3,6 +3,7 @@ pub mod heatmaps;
 pub mod line_plots;
 pub mod scatter_plots;
 pub mod stairs_plots;
+mod stem_plots;
 pub mod text_plots;
 
 use imgui::{im_str, Condition, Ui, Window};
@@ -43,5 +44,9 @@ pub fn show_demos(ui: &Ui, plot_ui: &PlotUi) {
             ui.separator();
             ui.text(im_str!("Heatmaps:"));
             heatmaps::show_demo_headers(ui, plot_ui);
+
+            ui.separator();
+            ui.text(im_str!("Stem plots:"));
+            stem_plots::show_demo_headers(ui, plot_ui);
         });
 }

implot-examples/examples-shared/src/line_plots.rs

@@ -3,12 +3,12 @@
 
 use imgui::{im_str, CollapsingHeader, Condition, Ui};
 use implot::{
-    get_plot_limits, get_plot_mouse_position, get_plot_query, is_plot_hovered, is_plot_queried,
-    pixels_to_plot_vec2, plot_to_pixels_vec2, push_style_color, push_style_var_f32,
-    push_style_var_i32, set_colormap_from_preset, set_colormap_from_vec, set_plot_y_axis,
-    AxisFlags, Colormap, ImPlotLimits, ImPlotPoint, ImPlotRange, ImVec2, ImVec4, Marker, Plot,
-    PlotColorElement, PlotFlags, PlotLine, PlotLocation, PlotOrientation, PlotUi, StyleVar,
-    YAxisChoice,
+    get_plot_limits, get_plot_mouse_position, get_plot_query, is_legend_entry_hovered,
+    is_plot_hovered, is_plot_queried, pixels_to_plot_vec2, plot_to_pixels_vec2, push_style_color,
+    push_style_var_f32, push_style_var_i32, set_colormap_from_preset, set_colormap_from_vec,
+    set_plot_y_axis, AxisFlags, Colormap, ImPlotLimits, ImPlotPoint, ImPlotRange, ImVec2, ImVec4,
+    Marker, Plot, PlotColorElement, PlotFlags, PlotLine, PlotLocation, PlotOrientation, PlotUi,
+    StyleVar, YAxisChoice,
 };
 
 pub fn show_basic_plot(ui: &Ui, plot_ui: &PlotUi) {
@@ -156,6 +156,8 @@ pub fn show_query_features_plot(ui: &Ui, plot_ui: &PlotUi) {
     let mut hover_pos_from_pixels: Option<ImPlotPoint> = None;
     let mut plot_limits: Option<ImPlotLimits> = None;
     let mut query_limits: Option<ImPlotLimits> = None;
+    let mut legend1_hovered = false;
+    let mut legend2_hovered = false;
 
     // Draw a plot
     Plot::new("Plot querying")
@@ -183,6 +185,12 @@ pub fn show_query_features_plot(ui: &Ui, plot_ui: &PlotUi) {
                 None,
             ));
 
+            // Plot a line so we have a legend entry
+            PlotLine::new("Legend1").plot(&vec![2.0, 2.0], &vec![2.0, 1.0]);
+            PlotLine::new("Legend2").plot(&vec![0.0, 0.0], &vec![1.0, 1.0]);
+            legend1_hovered = is_legend_entry_hovered("Legend1");
+            legend2_hovered = is_legend_entry_hovered("Legend2");
+
             if is_plot_queried() {
                 query_limits = Some(get_plot_query(None));
             }
@@ -214,6 +222,11 @@ pub fn show_query_features_plot(ui: &Ui, plot_ui: &PlotUi) {
     if let Some(query) = query_limits {
         ui.text(im_str!("Query limits are {:#?}", query));
     }
+    ui.text(im_str!(
+        "Legend hovering - 1: {}, 2: {}",
+        legend1_hovered,
+        legend2_hovered
+    ));
 
     // Try out converting pixel position to plot position
     if let Some(pos) = hover_pos_from_pixels {

implot-examples/examples-shared/src/stem_plots.rs

@@ -0,0 +1,28 @@
+//! This example demonstrates how stem plots are to be used. For more general
+//! features of the libray, see the line_plots example.
+
+use imgui::{im_str, CollapsingHeader, Ui};
+use implot::{Plot, PlotStems, PlotUi};
+
+pub fn show_basic_plot(ui: &Ui, plot_ui: &PlotUi) {
+    ui.text(im_str!("This header shows a simple stem plot."));
+    let content_width = ui.window_content_region_width();
+    Plot::new("Stem plot")
+        // The size call could also be omitted, though the defaults don't consider window
+        // width, which is why we're not doing so here.
+        .size(content_width, 300.0)
+        .build(plot_ui, || {
+            // If this is called outside a plot build callback, the program will panic.
+            let axis_positions = vec![0.2, 0.4, 0.6, 0.8, 0.9, 0.93];
+            let values = vec![0.1, 0.2, 0.3, 0.4, 0.3, 0.8];
+            PlotStems::new("legend label")
+                .with_reference_y(0.1)
+                .plot(&axis_positions, &values);
+        });
+}
+
+pub fn show_demo_headers(ui: &Ui, plot_ui: &PlotUi) {
+    if CollapsingHeader::new(im_str!("Stem plots")).build(&ui) {
+        show_basic_plot(&ui, &plot_ui);
+    }
+}

src/lib.rs

@@ -20,6 +20,7 @@ use implot_sys as sys;
 
 // TODO(4bb4) facade-wrap these?
 pub use self::{context::*, plot::*, plot_elements::*};
+use imgui::im_str;
 pub use sys::{ImPlotLimits, ImPlotPoint, ImPlotRange, ImVec2, ImVec4};
 
 mod context;
@@ -572,6 +573,11 @@ pub fn is_plot_y_axis_hovered(y_axis_choice: Option<YAxisChoice>) -> bool {
     unsafe { sys::ImPlot_IsPlotYAxisHovered(y_axis_choice_i32) }
 }
 
+/// Returns true if the given item in the legend of the current plot is hovered.
+pub fn is_legend_entry_hovered(legend_entry: &str) -> bool {
+    unsafe { sys::ImPlot_IsLegendEntryHovered(im_str!("{}", legend_entry).as_ptr() as *const i8) }
+}
+
 // --- Demo window -------------------------------------------------------------------------------
 /// Show the demo window for poking around what functionality implot has to
 /// offer. Note that not all of this is necessarily implemented in implot-rs

src/plot_elements.rs

@@ -147,7 +147,7 @@ impl PlotBars {
 
     /// Draw a previously-created bar plot. Use this in closures passed to
     /// [`Plot::build()`](struct.Plot.html#method.build). The `axis_positions`
-    /// specify where on the corersponding axis (X for vertical mode, Y for horizontal mode) the
+    /// specify where on the corresponding axis (X for vertical mode, Y for horizontal mode) the
     /// bar is drawn, and the `bar_values` specify what values the bars have.
     pub fn plot(&self, axis_positions: &[f64], bar_values: &[f64]) {
         let number_of_points = axis_positions.len().min(bar_values.len());
@@ -332,3 +332,51 @@ impl PlotHeatmap {
         }
     }
 }
+
+/// Struct to provide stem plotting functionality.
+pub struct PlotStems {
+    /// Label to show in the legend for this line
+    label: String,
+
+    /// Reference value for the y value, which the stems are "with respect to"
+    reference_y: f64,
+}
+
+impl PlotStems {
+    /// Create a new stem plot to be shown. Does not draw anything by itself, call
+    /// [`PlotStems::plot`] on the struct for that.
+    pub fn new(label: &str) -> Self {
+        Self {
+            label: label.to_owned(),
+            reference_y: 0.0, // Default value taken from C++ implot
+        }
+    }
+
+    /// Set the reference y value for the stems
+    pub fn with_reference_y(mut self, reference_y: f64) -> Self {
+        self.reference_y = reference_y;
+        self
+    }
+
+    /// Draw a previously-created stem plot. Use this in closures passed to
+    /// [`Plot::build()`](struct.Plot.html#method.build). The `axis_positions` specify where on the
+    /// X axis the stems are drawn, and the `stem_values` specify what values the stems have.
+    pub fn plot(&self, axis_positions: &[f64], stem_values: &[f64]) {
+        let number_of_points = axis_positions.len().min(stem_values.len());
+        // If there is no data to plot, we stop here
+        if number_of_points == 0 {
+            return;
+        }
+        unsafe {
+            sys::ImPlot_PlotStemsdoublePtrdoublePtr(
+                im_str!("{}", self.label).as_ptr() as *const i8,
+                axis_positions.as_ptr(),
+                stem_values.as_ptr(),
+                number_of_points as i32, // "as" casts saturate as of Rust 1.45. This is safe here.
+                self.reference_y,
+                0,                                 // No offset
+                std::mem::size_of::<f64>() as i32, // Stride, set to one f64 for the standard use case
+            );
+        }
+    }
+}