Added legend location setting

README.md

@@ -74,13 +74,13 @@ created for 64-bit floats.
   - [ ] Annotations
   - [ ] Dragline
   - [ ] Dragpoint
-- [ ] Plot customization
+- [x] Plot customization
   - [x] Axis flags
   - [x] Styling colors
   - [x] Styling variables
   - [x] Colormaps
-  - [ ] Legend locations
+  - [x] Legend locations
-- [x] Plot querying 
+- [ ] Plot querying 
   - [x] is hovered
   - [x] mouse position in plot
   - [x] plot limits
@@ -88,6 +88,7 @@ created for 64-bit floats.
   - [x] get plot query
   - [x] are axes hovered
   - [x] Choice of y axis
+  - [ ] Are legend entries hovered
 - [ ] Utils
   - [x] Plot limit setting
   - [x] imgui-rs style safe push/pop stacks

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

@@ -6,8 +6,8 @@ use implot::{
     get_plot_limits, get_plot_mouse_position, get_plot_query, is_plot_hovered, is_plot_queried,
     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, ImVec4, Marker, Plot, PlotColorElement, PlotFlags, PlotLine, PlotUi, StyleVar,
+    ImPlotRange, ImVec4, Marker, Plot, PlotColorElement, PlotFlags, PlotLine, PlotLocation,
-    YAxisChoice,
+    PlotOrientation, PlotUi, StyleVar, YAxisChoice,
 };
 
 pub fn show_basic_plot(ui: &Ui, plot_ui: &PlotUi) {
@@ -121,8 +121,9 @@ pub fn show_configurable_plot(ui: &Ui, plot_ui: &PlotUi) {
         .with_plot_flags(&plot_flags)
         .with_x_axis_flags(&x_axis_flags)
         .with_y_axis_flags(YAxisChoice::First, &y_axis_flags)
+        .with_legend_location(&PlotLocation::West, &PlotOrientation::Horizontal, true)
         .build(plot_ui, || {
-            PlotLine::new("A line").plot(&vec![2.1, 2.9], &vec![1.1, 1.9]);
+            PlotLine::new("A line 2").plot(&vec![2.4, 2.9], &vec![1.1, 1.9]);
         });
 }
 

src/lib.rs

@@ -37,11 +37,11 @@ const NUMBER_OF_Y_AXES: usize = 3;
 // so we can store data about individual axes in arrays, so this pretty much should stay
 // just a mapping of words to numbers.
 #[derive(Clone)]
-#[repr(i32)]
+#[repr(u32)]
 pub enum YAxisChoice {
-    First = 0,
+    First = sys::ImPlotYAxis__ImPlotYAxis_1,
-    Second = 1,
+    Second = sys::ImPlotYAxis__ImPlotYAxis_2,
-    Third = 2,
+    Third = sys::ImPlotYAxis__ImPlotYAxis_3,
 }
 
 /// A temporary reference for building plots. This does not really do anything on its own at
@@ -51,7 +51,7 @@ pub struct PlotUi<'ui> {
     context: &'ui Context,
 }
 
-// --- Markers, color maps, style variables----------------------------------------------------
+// --- Markers, color maps, style variables, legend location ----------------------------------
 /// Markers, documentation copied from implot.h for convenience.
 #[repr(i32)]
 #[derive(Copy, Clone, Debug)]
@@ -221,6 +221,38 @@ pub enum StyleVar {
     PlotMinSize = sys::ImPlotStyleVar__ImPlotStyleVar_PlotMinSize,
 }
 
+/// Used to position items on a plot (e.g. legends, labels, etc.)
+#[repr(u32)]
+#[derive(Copy, Clone, Debug)]
+pub enum PlotLocation {
+    /// Center-center
+    Center = sys::ImPlotLocation__ImPlotLocation_Center,
+    /// Top-center
+    North = sys::ImPlotLocation__ImPlotLocation_North,
+    /// Bottom-center
+    South = sys::ImPlotLocation__ImPlotLocation_South,
+    /// Center-left
+    West = sys::ImPlotLocation__ImPlotLocation_West,
+    /// Center-right
+    East = sys::ImPlotLocation__ImPlotLocation_East,
+    /// Top-left
+    NorthWest = sys::ImPlotLocation__ImPlotLocation_NorthWest,
+    /// Top-right
+    NorthEast = sys::ImPlotLocation__ImPlotLocation_NorthEast,
+    /// Bottom-left
+    SouthWest = sys::ImPlotLocation__ImPlotLocation_SouthWest,
+    /// Bottom-right
+    SouthEast = sys::ImPlotLocation__ImPlotLocation_SouthEast,
+}
+
+/// Used to orient items on a plot (e.g. legends, labels, etc.)
+#[repr(u32)]
+#[derive(Copy, Clone, Debug)]
+pub enum PlotOrientation {
+    Horizontal = sys::ImPlotOrientation__ImPlotOrientation_Horizontal,
+    Vertical = sys::ImPlotOrientation__ImPlotOrientation_Vertical,
+}
+
 /// Switch to one of the built-in preset colormaps. If samples is greater than 1, the map will be
 /// linearly resampled.
 pub fn set_colormap_from_preset(preset: Colormap, samples: u32) {

src/plot.rs

@@ -2,7 +2,7 @@
 //!
 //! This module defines the `Plot` struct, which is used to create a 2D plot that will
 //! contain all other objects that can be created using this library.
-use crate::{Context, PlotUi, YAxisChoice, NUMBER_OF_Y_AXES};
+use crate::{Context, PlotLocation, PlotOrientation, PlotUi, YAxisChoice, NUMBER_OF_Y_AXES};
 use bitflags::bitflags;
 pub use imgui::Condition;
 use imgui::{im_str, ImString};
@@ -133,6 +133,12 @@ pub struct Plot {
     y_tick_labels: [Option<Vec<ImString>>; NUMBER_OF_Y_AXES],
     /// Whether to also show the default Y ticks when showing custom ticks or not
     show_y_default_ticks: [bool; NUMBER_OF_Y_AXES],
+    /// Orientation of the legend
+    legend_orientation: PlotOrientation,
+    /// Location of the legend
+    legend_location: PlotLocation,
+    /// Whether the legend is shown outside the plot
+    legend_outside_plot: bool,
     /// Flags relating to the plot TODO(4bb4) make those into bitflags
     plot_flags: sys::ImPlotFlags,
     /// Flags relating to the X axis of the plot TODO(4bb4) make those into bitflags
@@ -166,6 +172,9 @@ impl Plot {
             y_tick_positions: [POS_NONE; NUMBER_OF_Y_AXES],
             y_tick_labels: [TICK_NONE; NUMBER_OF_Y_AXES],
             show_y_default_ticks: [false; NUMBER_OF_Y_AXES],
+            legend_location: PlotLocation::NorthWest,
+            legend_orientation: PlotOrientation::Vertical,
+            legend_outside_plot: false,
             plot_flags: PlotFlags::ANTIALIASED.bits() as sys::ImPlotFlags,
             x_flags: AxisFlags::NONE.bits() as sys::ImPlotAxisFlags,
             y_flags: [AxisFlags::NONE.bits() as sys::ImPlotAxisFlags; NUMBER_OF_Y_AXES],
@@ -299,6 +308,20 @@ impl Plot {
         self
     }
 
+    /// Set the legend location, orientation and whether it is to be drawn outside the plot
+    #[inline]
+    pub fn with_legend_location(
+        mut self,
+        location: &PlotLocation,
+        orientation: &PlotOrientation,
+        outside: bool,
+    ) -> Self {
+        self.legend_location = *location;
+        self.legend_orientation = *orientation;
+        self.legend_outside_plot = outside;
+        self
+    }
+
     /// Internal helper function to set axis limits in case they are specified.
     fn maybe_set_axis_limits(&self) {
         // Set X limits if specified
@@ -415,6 +438,19 @@ impl Plot {
         };
 
         if should_render {
+            // Configure legend location. This has to be called between begin() and end(),
+            // but since only the last call to it actually affects the outcome, I'm adding
+            // it here instead of as a freestanding function. If this is too restrictive
+            // (for example, if you want to set the location based on code running _during_
+            // the plotting for some reason), file an issue and we'll move it.
+            unsafe {
+                sys::ImPlot_SetLegendLocation(
+                    self.legend_location as i32,
+                    self.legend_orientation as i32,
+                    self.legend_outside_plot,
+                )
+            }
+
             Some(PlotToken {
                 context: plot_ui.context,
                 plot_title: self.title.clone(),