Added scatter plot support

implot-examples/examples/line_plots.rs

@@ -179,8 +179,7 @@ fn main() {
                 ui.text(im_str!("Hello from implot-rs!"));
                 ui.text_wrapped(im_str!(
                     "The headers here demo the line plotting features of the library. \
-                    Have a look at the example source code to \
+                    Have a look at the example source code to see how they are implemented.\n\
-                    see how they are implemented.\n\
                     Check out the demo from ImPlot itself first \
                     (by enabling the 'Show demo' checkbox) for instructions \
                     on how to interact with ImPlot plots."

implot-examples/examples/scatter_plot.rs

@@ -0,0 +1,88 @@
+//! This example demonstrates how scatter plots are to be used. For more general
+//! features of the libray, see the line_plots example.
+
+use imgui::{im_str, CollapsingHeader, Condition, Ui, Window};
+use implot::{push_style_var_f32, push_style_var_u32, Marker, Plot, PlotScatter, StyleVar};
+
+mod support;
+
+fn show_basic_plot(ui: &Ui) {
+    ui.text(im_str!(
+        "This header just plots a line with as little code as possible."
+    ));
+    let content_width = ui.window_content_region_width();
+    Plot::new("Simple scatter 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(|| {
+            // If this is called outside a plot build callback, the program will panic.
+            let x_positions = vec![0.1, 0.2, 0.1, 0.5, 0.9];
+            let y_positions = vec![0.1, 0.1, 0.3, 0.3, 0.9];
+            PlotScatter::new("legend label").plot(&x_positions, &y_positions);
+        });
+}
+
+fn show_custom_markers_plot(ui: &Ui) {
+    ui.text(im_str!(
+        "This header just plots a line with as little code as possible."
+    ));
+    let content_width = ui.window_content_region_width();
+    Plot::new("Simple scatter 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(|| {
+            // Change to cross marker for one scatter plot call
+            let x_positions = vec![0.1, 0.2, 0.1, 0.5, 0.9];
+            let y_positions = vec![0.1, 0.1, 0.3, 0.3, 0.9];
+            let markerchoice = push_style_var_u32(&StyleVar::Marker, Marker::CROSS.bits());
+            PlotScatter::new("legend label 1").plot(&x_positions, &y_positions);
+            markerchoice.pop();
+
+            // One can combine things like marker size and markor choice
+            let x_positions = vec![0.4, 0.1];
+            let y_positions = vec![0.5, 0.3];
+            let marker_choice = push_style_var_u32(&StyleVar::Marker, Marker::DIAMOND.bits());
+            let marker_size = push_style_var_f32(&StyleVar::MarkerSize, 12.0);
+            PlotScatter::new("legend label 2").plot(&x_positions, &y_positions);
+
+            // TODO(4bb4) check if these have to be in reverse push order
+            marker_size.pop();
+            marker_choice.pop();
+        });
+}
+
+fn main() {
+    let system = support::init(file!());
+    let mut showing_demo = false;
+    system.main_loop(move |_, ui| {
+        Window::new(im_str!("Line plots example"))
+            .size([430.0, 450.0], Condition::FirstUseEver)
+            .build(ui, || {
+                ui.text(im_str!("Hello from implot-rs!"));
+                ui.text_wrapped(im_str!(
+                    "The headers here demo the scatter plotting features of the library. \
+                    Have a look at the example source code to see how they are implemented.\n\
+                    Check out the demo from ImPlot itself first \
+                    (by enabling the 'Show demo' checkbox) for instructions \
+                    on how to interact with ImPlot plots."
+                ));
+
+                ui.checkbox(im_str!("Show demo"), &mut showing_demo);
+
+                // Show individual examples in collapsed headers
+                if CollapsingHeader::new(im_str!("Basic scatter plot")).build(&ui) {
+                    show_basic_plot(&ui);
+                }
+
+                if CollapsingHeader::new(im_str!("Custom markers")).build(&ui) {
+                    show_custom_markers_plot(&ui);
+                }
+            });
+
+        if showing_demo {
+            implot::show_demo_window(&mut showing_demo);
+        }
+    });
+}

implot-examples/examples/text_plots.rs

@@ -40,8 +40,7 @@ fn main() {
                 ui.text(im_str!("Hello from implot-rs!"));
                 ui.text_wrapped(im_str!(
                     "The headers here demo the text plotting features of the library. \
-                    Have a look at the example source code to see how they are \
+                    Have a look at the example source code to see how they are implemented.\n\
-                    implemented.\n\
                     Check out the demo from ImPlot itself first \
                     (by enabling the 'Show demo' checkbox) for instructions \
                     on how to interact with ImPlot plots."

src/lib.rs

@@ -442,6 +442,40 @@ impl PlotLine {
     }
 }
 
+/// Struct to provide functionality for creating a scatter plot
+pub struct PlotScatter {
+    /// Label to show in the legend for this line
+    label: String,
+}
+
+impl PlotScatter {
+    /// Create a new scatter plot to be shown. Does not draw anything yet.
+    pub fn new(label: &str) -> Self {
+        Self {
+            label: label.to_owned(),
+        }
+    }
+
+    /// Draw a previously-created scatter plot. Use this in closures passed to
+    /// [`Plot::build()`](struct.Plot.html#method.build)
+    pub fn plot(&self, x: &Vec<f64>, y: &Vec<f64>) {
+        // If there is no data to plot, we stop here
+        if x.len().min(y.len()) == 0 {
+            return;
+        }
+        unsafe {
+            sys::ImPlot_PlotScatterdoublePtrdoublePtr(
+                im_str!("{}", self.label).as_ptr() as *const i8,
+                x.as_ptr(),
+                y.as_ptr(),
+                x.len().min(y.len()) as i32, // "as" casts saturate as of Rust 1.45. This is safe here.
+                0,                           // No offset
+                std::mem::size_of::<f64>() as i32, // Stride, set to one f64 for the standard use case
+            );
+        }
+    }
+}
+
 /// Struct to provide functionality for adding text within a plot
 pub struct PlotText {
     /// Label to show in plot