1 files changed, 77 insertions, 0 deletions
diff --git a/packages/svgbob/src/buffer/fragment_buffer/direction.rs b/packages/svgbob/src/buffer/fragment_buffer/direction.rs
new file mode 100644
index 0000000..4325db1
--- /dev/null
+++ b/packages/svgbob/src/buffer/fragment_buffer/direction.rs
@@ -0,0 +1,77 @@
+use crate::buffer::CellGrid;
+
+#[derive(Debug, Clone, PartialEq, Copy)]
+pub enum Direction {
+    TopLeft,
+    Top,
+    TopRight,
+    Left,
+    Right,
+    BottomLeft,
+    Bottom,
+    BottomRight,
+}
+
+impl Direction {
+    /// return the opposite direction of self
+    pub(crate) fn opposite(&self) -> Self {
+        match self {
+            Direction::TopLeft => Direction::BottomRight,
+            Direction::Top => Direction::Bottom,
+            Direction::TopRight => Direction::BottomLeft,
+            Direction::Left => Direction::Right,
+            Direction::Right => Direction::Left,
+            Direction::BottomLeft => Direction::TopRight,
+            Direction::Bottom => Direction::Top,
+            Direction::BottomRight => Direction::TopLeft,
+        }
+    }
+    /*
+    pub(crate) fn any_along_side(&self, tags: &[PolygonTag]) -> bool {
+        tags.iter().any(|tag| self.is_along_side(tag))
+    }
+    /// diamon matches alongside for everything.
+    pub(crate) fn is_along_side(&self, tag: &PolygonTag) -> bool {
+        if *tag == PolygonTag::DiamondBullet {
+            return true;
+        }
+        match self {
+            Direction::TopLeft | Direction::BottomRight => match tag {
+                PolygonTag::ArrowTopLeft
+                | PolygonTag::ArrowBottomRight
+                | PolygonTag::ArrowTop
+                | PolygonTag::ArrowBottom => true,
+                _ => false,
+            },
+            Direction::Top | Direction::Bottom => match tag {
+                PolygonTag::ArrowTop | PolygonTag::ArrowBottom => true,
+                _ => false,
+            },
+            Direction::TopRight | Direction::BottomLeft => match tag {
+                PolygonTag::ArrowTopRight
+                | PolygonTag::ArrowBottomLeft
+                | PolygonTag::ArrowTop
+                | PolygonTag::ArrowBottom => true,
+                _ => false,
+            },
+            Direction::Left | Direction::Right => match tag {
+                PolygonTag::ArrowLeft | PolygonTag::ArrowRight => true,
+                _ => false,
+            },
+        }
+    }
+    */
+
+    /// calculate the threshold length which is the basis
+    /// if the arrow and the line is connected
+    pub(crate) fn threshold_length(&self) -> f32 {
+        match self {
+            Direction::TopLeft
+            | Direction::TopRight
+            | Direction::BottomLeft
+            | Direction::BottomRight => CellGrid::diagonal_length(),
+            Direction::Left | Direction::Right => CellGrid::width(),
+            Direction::Top | Direction::Bottom => CellGrid::height(),
+        }
+    }
+}