Add file explorer and tree helper

ref: https://github.com/helix-editor/helix/issues/200
ref: https://github.com/helix-editor/helix/pull/2377
ref: https://github.com/helix-editor/helix/pull/5566
ref: https://github.com/helix-editor/helix/pull/5768

Co-authored-by: cossonleo <cossonleo@foxmail.com>
Co-authored-by: wongjiahau <hou32hou@gmail.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/helix-view/src/graphics.rs b/helix-view/src/graphics.rs
index 046db86a..fbfde635 100644
--- a/helix-view/src/graphics.rs
+++ b/helix-view/src/graphics.rs
@@ -248,6 +248,34 @@ impl Rect {
             && self.y < other.y + other.height
             && self.y + self.height > other.y
     }
+
+    /// Returns a smaller `Rect` with a margin of 5% on each side, and an additional 2 rows at the bottom
+    pub fn overlaid(self) -> Rect {
+        self.clip_bottom(2).clip_relative(90, 90)
+    }
+
+    /// Returns a smaller `Rect` with width and height clipped to the given `percent_horizontal`
+    /// and `percent_vertical`.
+    ///
+    /// Value of `percent_horizontal` and `percent_vertical` is from 0 to 100.
+    pub fn clip_relative(self, percent_horizontal: u8, percent_vertical: u8) -> Rect {
+        fn mul_and_cast(size: u16, factor: u8) -> u16 {
+            ((size as u32) * (factor as u32) / 100).try_into().unwrap()
+        }
+
+        let inner_w = mul_and_cast(self.width, percent_horizontal);
+        let inner_h = mul_and_cast(self.height, percent_vertical);
+
+        let offset_x = self.width.saturating_sub(inner_w) / 2;
+        let offset_y = self.height.saturating_sub(inner_h) / 2;
+
+        Rect {
+            x: self.x + offset_x,
+            y: self.y + offset_y,
+            width: inner_w,
+            height: inner_h,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]