From eb1bd01179c4c5cb5016a65e189cc0e5b1f33276 Mon Sep 17 00:00:00 2001
From: dbr <dbr.onix@gmail.com>
Date: Tue, 12 Oct 2021 13:24:50 +1100
Subject: [PATCH] Add basic polyline methods to draw list

---
 imgui-examples/examples/draw_list.rs | 40 +++++++++++++
 imgui/src/draw_list.rs               | 85 ++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+)

diff --git a/imgui-examples/examples/draw_list.rs b/imgui-examples/examples/draw_list.rs
index f575e77..3294114 100644
--- a/imgui-examples/examples/draw_list.rs
+++ b/imgui-examples/examples/draw_list.rs
@@ -93,5 +93,45 @@ fn main() {
                     [1.0, 1.0, 1.0],
                 );
             });
+
+        ui.window("Polygons")
+            .size([300.0, 150.0], Condition::FirstUseEver)
+            .position([400.0, 110.0], Condition::FirstUseEver)
+            .scroll_bar(false)
+            .build(|| {
+                let draw_list = ui.get_window_draw_list();
+
+                // Origin
+                let o = ui.cursor_screen_pos();
+
+                draw_list
+                    .add_polyline(
+                        vec![
+                            [o[0] + 0.0, o[1] + 0.0],
+                            [o[0] + 100.0, o[1] + 25.0],
+                            [o[0] + 50.0, o[1] + 50.0],
+                            [o[0] + 100.0, o[1] + 75.0],
+                            [o[0] + 0.0, o[1] + 100.0],
+                            [o[0] + 0.0, o[1] + 0.0],
+                        ],
+                        [1.0, 0.0, 1.0]
+                    )
+                    .build();
+
+                draw_list
+                    .add_polyline(
+                        vec![
+                            [o[0] + 120.0 + 0.0, o[1] + 0.0],
+                            [o[0] + 120.0 + 100.0, o[1] + 25.0],
+                            [o[0] + 120.0 + 50.0, o[1] + 50.0],
+                            [o[0] + 120.0 + 100.0, o[1] + 75.0],
+                            [o[0] + 120.0 + 0.0, o[1] + 100.0],
+                            [o[0] + 120.0 + 0.0, o[1] + 0.0],
+                        ],
+                        [0.0, 1.0, 1.0]
+                    )
+                    .filled(true)
+                    .build();
+            });
     });
 }
diff --git a/imgui/src/draw_list.rs b/imgui/src/draw_list.rs
index d58ef6d..d810f57 100644
--- a/imgui/src/draw_list.rs
+++ b/imgui/src/draw_list.rs
@@ -226,6 +226,22 @@ impl<'ui> DrawListMut<'ui> {
         Line::new(self, p1, p2, c)
     }
 
+    /// Returns a polygonal line. If filled is rendered as a convex
+    /// polygon, if not filled is drawn as a line specified by
+    /// [`PolyLine::thickness`] (default 1.0)
+    #[doc(alias = "AddPolyline", alias = "AddConvexPolyFilled")]
+    pub fn add_polyline<C, P>(
+        &'ui self,
+        points: Vec<P>,
+        c: C,
+    ) -> Polyline<'ui>
+    where
+        C: Into<ImColor32>,
+        P: Into<MintVec2>,
+    {
+        Polyline::new(self, points, c)
+    }
+
     /// Returns a rectangle whose upper-left corner is at point `p1`
     /// and lower-right corner is at point `p2`, with color `c`.
     #[doc(alias = "AddRectFilled", alias = "AddRect")]
@@ -489,6 +505,75 @@ impl<'ui> Line<'ui> {
     }
 }
 
+/// Represents a poly line about to be drawn
+#[must_use = "should call .build() to draw the object"]
+pub struct Polyline<'ui> {
+    points: Vec<[f32; 2]>,
+    thickness: f32,
+    filled: bool,
+    color: ImColor32,
+    draw_list: &'ui DrawListMut<'ui>,
+}
+
+impl<'ui> Polyline<'ui> {
+    fn new<C, P>(
+        draw_list: &'ui DrawListMut<'_>,
+        points: Vec<P>,
+        c: C,
+    ) -> Self
+    where
+        C: Into<ImColor32>,
+        P: Into<MintVec2>,
+    {
+        Self {
+            points: points.into_iter().map(|p| p.into().into()).collect(),
+            color: c.into(),
+            thickness: 1.0,
+            filled: false,
+            draw_list,
+        }
+    }
+
+    /// Set line's thickness (default to 1.0 pixel). Has no effect if
+    /// shape is filled
+    pub fn thickness(mut self, thickness: f32) -> Self {
+        self.thickness = thickness;
+        self
+    }
+
+    /// Draw shape as filled convex polygon
+    pub fn filled(mut self, filled: bool) -> Self {
+        self.filled = filled;
+        self
+    }
+
+    /// Draw the line on the window
+    pub fn build(self) {
+        if self.filled {
+            unsafe {
+                sys::ImDrawList_AddConvexPolyFilled(
+                    self.draw_list.draw_list,
+                    self.points.as_slice().as_ptr() as *const sys::ImVec2,
+                    self.points.len() as i32,
+                    self.color.into(),
+                )
+            }
+        } else {
+            unsafe {
+                sys::ImDrawList_AddPolyline(
+                    self.draw_list.draw_list,
+                    self.points.as_slice().as_ptr() as *const sys::ImVec2,
+                    self.points.len() as i32,
+                    self.color.into(),
+                    sys::ImDrawFlags::default(),
+                    self.thickness,
+                )
+            }
+        }
+    }
+}
+
+
 /// Represents a rectangle about to be drawn
 #[must_use = "should call .build() to draw the object"]
 pub struct Rect<'ui> {