### Construct Polyline View from New Start Point

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_view.rs.html

Creates a polyline view starting from a specified point on a source polyline. Handles cases where the start point is exactly at a vertex or on a segment. Panics if the source has fewer than 2 vertices or the start index is out of range.

```rust
pub fn from_new_start<T, P>(source: &P, start_point: Vector2<T>, start_index: usize, pos_equal_eps: T) -> Option<Self> where P: PlineSource<Num = T> + ?Sized {
        // check if open polyline then just delegate to slice points method
        if !source.is_closed() {
            return Self::from_slice_points(
                source,
                start_point,
                start_index,
                source.last()?.pos(),
                source.vertex_count() - 1,
                pos_equal_eps,
            );
        }

        let vc = source.vertex_count();
        assert!(
            vc >= 2,
            "source must have at least 2 vertexes to form view data"
        );

        // catch where start point is at very end of start index segment (and adjust forward)
        let start_index = {
            let next_index = source.next_wrapping_index(start_index);
            if source
                .at(next_index)
                .pos()
                .fuzzy_eq_eps(start_point, pos_equal_eps)
            {
                next_index
            } else {
                start_index
            }
        };

        let start_v1 = source.at(start_index);
        let start_v2 = source.at(source.next_wrapping_index(start_index));
        let split = seg_split_at_point(start_v1, start_v2, start_point, pos_equal_eps);

        let (end_index_offset, updated_end_bulge) =
            if start_v1.pos().fuzzy_eq_eps(start_point, pos_equal_eps) {
                // start point on top of vertex, adjust index offset and do not use split bulge
                (
                    vc - 1,
                    source.at(source.prev_wrapping_index(start_index)).bulge,
                )
            } else {
                (vc, split.updated_start.bulge)
            };

        let view_data = Self {
            start_index,
            end_index_offset,
            updated_start: split.split_vertex,
            updated_end_bulge,
            end_point: start_point,
            inverted_direction: false,
        };

        debug_assert_eq!(
            view_data.validate_for_source(source),
            ViewDataValidation::IsValid
        );

        Some(view_data)
    }
```

--------------------------------

### Set Vertex Example

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/trait.PlineSourceMut.html

Demonstrates updating a specific vertex in a polyline.

```rust
let mut polyline = Polyline::new();
polyline.add(0.0, 0.0, 0.0);
polyline.set_vertex(0, PlineVertex::new(1.0, 1.0, 1.0));
assert!(polyline.at(0).fuzzy_eq(PlineVertex::new(1.0, 1.0, 1.0)));
```

--------------------------------

### Vector2 Usage Examples

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/core/math/vector2.rs.html

Demonstrates creating vectors and performing basic mathematical operations.

```rust
# use cavalier_contours::core::math::{Vector2, vec2};
let v1 = Vector2::new(3.0, 4.0);
let v2 = vec2(1.0, 2.0); // shorthand constructor

// Vector operations
let sum = v1 + v2;
let dot_product = v1.dot(v2);
let length = v1.length();
let normalized = v1.normalize();
```

--------------------------------

### Clear Polyline Example

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/trait.PlineSourceMut.html

Demonstrates removing all vertices from a polyline.

```rust
let mut polyline = Polyline::new();
polyline.add(0.0, 0.0, 0.0);
assert_eq!(polyline.vertex_count(), 1);
polyline.clear();
assert_eq!(polyline.vertex_count(), 0);
```

--------------------------------

### from_new_start

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_view.rs.html

Constructs a view of a polyline starting from a specific point and index, handling both open and closed polylines.

```APIDOC
## from_new_start

### Description
Constructs a view of a polyline starting from a specific point and index. If the polyline is closed, it calculates the view data based on the provided start point and index, adjusting for vertex positions.

### Parameters
#### Path Parameters
- **source** (P) - Required - The source polyline implementation.
- **start_point** (Vector2<T>) - Required - The starting coordinate.
- **start_index** (usize) - Required - The index to begin from.
- **pos_equal_eps** (T) - Required - Epsilon value for fuzzy equality checks.

### Response
- **Option<Self>** - Returns the constructed view data or None if construction fails.
```

--------------------------------

### Splitting an Arc Segment

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/fn.seg_split_at_point.html

Example demonstrating how to split an arc segment at a specific point.

```rust
// arc half circle arc segment going from (0, 0) to (1, 0) counter clockwise
let v1 = PlineVertex::new(0.0, 0.0, 1.0);
let v2 = PlineVertex::new(1.0, 0.0, 0.0);
let point = Vector2::new(0.5, -0.5);
let SplitResult { updated_start, split_vertex } = seg_split_at_point(v1, v2, point, 1e-5);
let quarter_circle_bulge = (std::f64::consts::PI / 8.0).tan();
assert!(updated_start.fuzzy_eq(PlineVertex::new(v1.x, v1.y, quarter_circle_bulge)));
assert!(split_vertex.fuzzy_eq(PlineVertex::new(point.x, point.y, quarter_circle_bulge)));
```

--------------------------------

### Construct an open polyline

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/macro.pline_open.html

Usage example for creating an open polyline with specific vertexes.

```rust
let polyline = pline_open![(0.0, 1.0, 1.0), (2.0, 0.0, 0.0)];
assert!(!polyline.is_closed());
assert_eq!(polyline[0], PlineVertex::new(0.0, 1.0, 1.0));
assert_eq!(polyline[1], PlineVertex::new(2.0, 0.0, 0.0));
```

--------------------------------

### min_max Usage Example

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/math/fn.min_max.html

Demonstrates how to use min_max to retrieve the minimum and maximum values from two integers.

```rust
let (min_val, max_val) = min_max(8, 4);
assert_eq!(min_val, 4);
assert_eq!(max_val, 8);
```

--------------------------------

### Set Closed State Example

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/trait.PlineSourceMut.html

Demonstrates toggling the closed state of a polyline.

```rust
let mut polyline: Polyline = Polyline::new();
assert!(!polyline.is_closed());
polyline.set_is_closed(true);
assert!(polyline.is_closed());
```

--------------------------------

### Construct Polyline View from Slice Points

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_view.rs.html

Creates a polyline view between two specified points on a source polyline, trimming the start and end of the source polyline. Handles cases where the start point is at the end of the first segment. Panics if the source has fewer than 2 vertices or indexes are out of range.

```rust
pub fn from_slice_points<T, P>(source: &P, start_point: Vector2<T>, start_index: usize, end_point: Vector2<T>, end_index: usize, pos_equal_eps: T) -> Option<Self> where P: PlineSource<Num = T> + ?Sized {
        debug_assert!(
            start_index <= end_index || source.is_closed(),
            "start index should be less than or equal to end index if polyline is open"
        );

        // catch if start_point is at end of first segment
        let (start_index, start_point_at_seg_end) = {
            if !source.is_closed() && start_index >= end_index {
                // not possible to wrap index forward
                (start_index, false)
            } else {
                let next_index = source.next_wrapping_index(start_index);
                if source
                    .at(next_index)
                    .pos()
                    .fuzzy_eq_eps(start_point, pos_equal_eps)
                {
                    (next_index, true)
                } else {
                    (start_index, false)
                }
            }
        };

        let traverse_count = {
            let index_dist = source.fwd_wrapping_dist(start_index, end_index);
            if index_dist == 0
                && source.is_closed()
                && !start_point.fuzzy_eq_eps(end_point, pos_equal_eps)
            {
                let seg_start = source.at(start_index).pos();
                let dist1 = dist_squared(seg_start, start_point);
                let dist2 = dist_squared(seg_start, end_point);
                if dist1 < dist2 {
                    // not wrapping around polyline, on same segment
                    0
                } else {
                    // wrapping around polyline back to same segment
                    // This part of the code is incomplete in the provided text.
                    // The original code likely continues here to determine traverse_count.
                }
            } else {
                index_dist
            }
        };

        // The rest of the function is not provided in the input text.
        // It would typically involve calculating segment splits and constructing the view data.
        unimplemented!("Polyline construction logic missing");
    }
```

--------------------------------

### Example: Creating view over polyline from slice points

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/struct.PlineViewData.html

Demonstrates how to create a PlineViewData from slice points and then construct a PlineView to perform operations on the selected portion of the polyline.

```APIDOC
### §Creating view over polyline from slice points
```rust
let mut polyline = Polyline::new_closed();
polyline.add(0.0, 0.0, 0.0);
polyline.add(5.0, 0.0, 0.0);
polyline.add(5.0, 5.0, 0.0);
polyline.add(0.0, 5.0, 0.0);

// construction view data from slice points, view data represents a slice of the source polyline
// starting at (2.5, 0.0) on the first segment (index 0) and ending at (2.5, 5.0) on the third
// segment (index 2)
let view_data = 
    PlineViewData::from_slice_points(
        // source polyline
        &polyline,
        // start point
        Vector2::new(2.5, 0.0),
        // segment index start point lies on
        0,
        // end point
        Vector2::new(2.5, 5.0),
        // segment index end point lies on
        2,
        // position equal epsilon
        1e-5).expect("slice not collapsed");

// construct the view (which implements polyline traits) from the view data and source
let view = view_data.view(&polyline);

// we can now use common trait methods on the slice
// note we never had to copy the source polyline
let slice_length = view.path_length();
assert_fuzzy_eq!(view.path_length(), 10.0);
let slice_vertex_count = view.vertex_count();
assert_eq!(slice_vertex_count, 4);
let slice_extents = view.extents().unwrap();
assert_fuzzy_eq!(slice_extents.min_x, 2.5);
assert_fuzzy_eq!(slice_extents.min_y, 0.0);
assert_fuzzy_eq!(slice_extents.max_x, 5.0);
assert_fuzzy_eq!(slice_extents.max_y, 5.0);
```
```

--------------------------------

### Calculate midpoint of polyline segments

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/fn.seg_midpoint.html

Examples demonstrating midpoint calculation for arc and line segments.

```rust
// counter clockwise half circle arc going from (2, 2) to (2, 4)
let v1 = PlineVertex::new(2.0, 2.0, 1.0);
let v2 = PlineVertex::new(4.0, 2.0, 0.0);
assert!(seg_midpoint(v1, v2).fuzzy_eq(Vector2::new(3.0, 1.0)));
```

```rust
// line segment going from (2, 2) to (4, 4)
let v1 = PlineVertex::new(2.0, 2.0, 0.0);
let v2 = PlineVertex::new(4.0, 4.0, 0.0);
assert!(seg_midpoint(v1, v2).fuzzy_eq(Vector2::new(3.0, 3.0)));
```

--------------------------------

### Example Usage of pline_open_userdata Macro

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/macro.pline_open_userdata.html

Demonstrates how to use the `pline_open_userdata` macro to create an open polyline and assert its properties. Requires `PlineVertex` and related methods.

```rust
let polyline = pline_open_userdata![vec![4, 117], (0.0, 1.0, 1.0), (2.0, 0.0, 0.0)];
assert!(!polyline.is_closed());
assert_eq!(polyline[0], PlineVertex::new(0.0, 1.0, 1.0));
assert_eq!(polyline[1], PlineVertex::new(2.0, 0.0, 0.0));
assert_eq!(polyline.get_userdata_count(), 2);
assert!(polyline.get_userdata_values().any(|x| x == 4));
assert!(polyline.get_userdata_values().any(|x| x == 117));
```

--------------------------------

### Example: Approximate Half Circle to Lines

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/traits.rs.html

Demonstrates converting a polyline with a half-circle arc into a series of line segments using `arcs_to_approx_lines` with a specified error distance.

```rust
let mut polyline = Polyline::new();
        // half circle
        polyline.add(0.0, 0.0, 1.0);
        polyline.add(2.0, 0.0, 0.0);
        let lines = polyline.arcs_to_approx_lines(0.1).unwrap();
        assert!(lines.vertex_count() > 2);
        assert!(lines.iter_vertexes().all(|v| v.bulge == 0.0));
```

--------------------------------

### Example Usage of pline_closed_userdata Macro

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/macro.pline_closed_userdata.html

Demonstrates constructing a closed polyline using the `pline_closed_userdata` macro and asserts its properties.

```rust
let polyline = pline_closed_userdata![vec![4, 117], (0.0, 1.0, 1.0), (2.0, 0.0, 0.0)];
assert!(polyline.is_closed());
assert_eq!(polyline[0], PlineVertex::new(0.0, 1.0, 1.0));
assert_eq!(polyline[1], PlineVertex::new(2.0, 0.0, 0.0));
assert_eq!(polyline.get_userdata_count(), 2);
assert!(polyline.get_userdata_values().any(|x| x == 4));
assert!(polyline.get_userdata_values().any(|x| x == 117));
```

--------------------------------

### Perform Vector Operations

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/math/struct.Vector2.html

Examples of creating vectors and performing common mathematical operations like addition, dot product, and normalization.

```rust
let v1 = Vector2::new(3.0, 4.0);
let v2 = vec2(1.0, 2.0); // shorthand constructor

// Vector operations
let sum = v1 + v2;
let dot_product = v1.dot(v2);
let length = v1.length();
let normalized = v1.normalize();
```

--------------------------------

### Example: Tangent-Intersecting Circles

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/math/fn.circle_circle_intr.html

Demonstrates finding a tangent intersection between two circles. Ensure the circles are positioned and sized to result in a single intersection point.

```rust
let r1 = 1.0;
let c1 = Vector2::new(0.0, 0.0);
let r2 = 1.0;
let c2 = Vector2::new(0.0, 2.0);
if let CircleCircleIntr::TangentIntersect { point: p } =
    circle_circle_intr(r1, c1, r2, c2, 1e-5)
{
    assert_eq!(p, Vector2::new(0.0, 1.0));
} else {
    unreachable!("expected a tangent intersection");
}

```

--------------------------------

### Example of tangent-intersecting line segment

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/math/fn.line_circle_intr.html

Demonstrates finding a tangent intersection where the line segment touches the circle at an endpoint.

```rust
// A line segment tangent-intersecting a circle with one of the line segments end points.
let p0 = Vector2::new(0.0, 0.0);
let p1 = Vector2::new(1.0, 0.0);
let r = 1.0;
let c = Vector2::new(0.0, 1.0);

if let LineCircleIntr::TangentIntersect{ t0: t } = line_circle_intr(p0, p1, r, c, 1e-5) {
    assert_eq!(t, 0.0);
} else {
    unreachable!("expected tangent intersect");
}
```

--------------------------------

### Example: Tangent Intersection

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/core/math/line_line_intersect.rs.html

Demonstrates a line segment intersecting a circle tangentially at one of its endpoints. Asserts the parametric values for the intersection.

```rust
# use cavalier_contours::core::traits::*;
# use cavalier_contours::core::math::*;
# use cavalier_contours::core::math::LineLineIntr::TrueIntersect;
// A line segment tangent-intersecting a circle with one of the line segments end points.
let v1 = Vector2::new(0.0, 0.0);
let v2 = Vector2::new(1.0, 0.0);
let u1 = Vector2::new(0.5, -1.0);
let u2 = Vector2::new(0.5, 1.0);
if let LineLineIntr::TrueIntersect {
    seg1_t: t1,
    seg2_t: t2,
} = line_line_intr(v1, v2, u1, u2, 1e-5)
{
    assert_eq!(t1, 0.5);
    assert_eq!(t2, 0.5);
} else {
    unreachable!("expected true intersection between line segments");
}

```

--------------------------------

### Fuzzy Equality Comparison Example

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/traits/trait.FuzzyEq.html

Demonstrates using fuzzy_eq to compare floating point values that would otherwise fail a direct equality check.

```rust
let a = 0.1 + 0.2;
let b = 0.3;

// Direct comparison would fail due to floating point precision
assert_ne!(a, b);

// Fuzzy comparison succeeds
assert!(a.fuzzy_eq(b));
```

--------------------------------

### Calculate Midpoint of Line Segment

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_seg.rs.html

This example demonstrates calculating the midpoint of a straight line segment. It requires `PlineVertex` and `Vector2` types.

```rust
# use cavalier_contours::polyline::*
# use cavalier_contours::core::math::*

// line segment going from (2, 2) to (4, 4)
let v1 = PlineVertex::new(2.0, 2.0, 0.0);
let v2 = PlineVertex::new(4.0, 4.0, 0.0);
assert!(seg_midpoint(v1, v2).fuzzy_eq(Vector2::new(3.0, 3.0)));
```

--------------------------------

### Get Vertex with Normal Direction

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_view.rs.html

Retrieves a vertex from the source polyline in the normal (non-inverted) direction. Handles the start vertex, intermediate vertices, the end segment vertex, and the final endpoint.

```rust
if index == 0 {
    return Some(self.updated_start);
}

if index < self.end_index_offset {
    let i = source.fwd_wrapping_index(self.start_index, index);
    return Some(source.at(i));
}

if index == self.end_index_offset {
    let i = source.fwd_wrapping_index(self.start_index, self.end_index_offset);
    let v = source.at(i);
    return Some(v.with_bulge(self.updated_end_bulge));
}

if index == self.end_index_offset + 1 {
    return Some(PlineVertex::from_vector2(self.end_point, T::zero()));
}
```

--------------------------------

### Compute Updated Start Vertex

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_view.rs.html

Calculates the updated start vertex for a polyline segment, considering start and end points, and whether the start point is at a segment end. This logic is used when the start and end points are on the same segment or different segments.

```rust
        // compute updated start vertex
        let updated_start = {
            let start_v1 = source.at(start_index);
            let start_v2 = source.at(source.next_wrapping_index(start_index));
            if start_point_at_seg_end {
                // start point on top of vertex no need to split using start_point
                if traverse_count == 0 {
                    // start and end point on same segment, split at end point
                    let split = seg_split_at_point(start_v1, start_v2, end_point, pos_equal_eps);
                    split.updated_start
                } else {
                    start_v1
                }
            } else {
                // split at start point
                let start_split =
                    seg_split_at_point(start_v1, start_v2, start_point, pos_equal_eps);
                let updated_for_start = start_split.split_vertex;
                if traverse_count == 0 {
                    // start and end point on same segment, split at end point
                    let split =
                        seg_split_at_point(updated_for_start, start_v2, end_point, pos_equal_eps);
                    split.updated_start
                } else {
                    updated_for_start
                }
            }
        };
```

--------------------------------

### Validate Updated Bulge Matches Start

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_view.rs.html

Checks if the updated bulge value matches the expected value from the start index segment. This is used when the end point is on the start index segment.

```rust
if self.end_index_offset == 0 {
            // end point on start index segment, check that updated bulge matches updated start
            // bulge
            if !self
                .updated_end_bulge
                .fuzzy_eq_eps(self.updated_start.bulge, validation_eps)
            {
                return ViewDataValidation::UpdatedBulgeDoesNotMatch {
                    updated_bulge: self.updated_end_bulge,
                    expected: self.updated_start.bulge,
                };
            }
        }

        ViewDataValidation::IsValid
```

--------------------------------

### Rotate Polyline Start Point

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/trait.PlineSource.html

Rotates the vertices of a closed polyline so that a specified point becomes the new start vertex. Ensure the polyline is closed and has sufficient length for rotation.

```rust
let mut polyline = Polyline::new_closed();
assert!(matches!(polyline.rotate_start(0, Vector2::new(0.0, 0.0), 1e-5), None));
polyline.add(0.0, 0.0, 0.0);
assert!(matches!(polyline.rotate_start(0, Vector2::new(0.0, 0.0), 1e-5), None));
polyline.add(1.0, 0.0, 0.0);
polyline.add(1.0, 1.0, 0.0);
polyline.add(0.0, 1.0, 0.0);

let rot = polyline.rotate_start(0, Vector2::new(0.5, 0.0), 1e-5).unwrap();
let mut expected_rot = Polyline::new_closed();
expected_rot.add(0.5, 0.0, 0.0);
expected_rot.add(1.0, 0.0, 0.0);
expected_rot.add(1.0, 1.0, 0.0);
expected_rot.add(0.0, 1.0, 0.0);
expected_rot.add(0.0, 0.0, 0.0);
assert!(rot.fuzzy_eq(&expected_rot));
```

--------------------------------

### Calculate Forward Wrapping Index

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/traits.rs.html

Computes a new index by applying an offset to a starting index, wrapping around the polyline length. Requires the start index to be valid and the offset to not exceed the polyline length.

```rust
# use cavalier_contours::polyline::*;
let mut polyline = Polyline::new_closed();
polyline.add(0.0, 0.0, 0.0);
polyline.add(0.0, 0.0, 0.0);
polyline.add(0.0, 0.0, 0.0);
polyline.add(0.0, 0.0, 0.0);
assert_eq!(polyline.fwd_wrapping_index(0, 2), 2);
assert_eq!(polyline.fwd_wrapping_index(1, 2), 3);
assert_eq!(polyline.fwd_wrapping_index(1, 3), 0);
assert_eq!(polyline.fwd_wrapping_index(2, 3), 1);
```

--------------------------------

### GET /polyline/orientation

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/traits.rs.html

Determines the orientation of a closed polyline (Clockwise or CounterClockwise).

```APIDOC
## GET /polyline/orientation

### Description
Returns the orientation of the polyline. If the polyline is not closed, it returns an Open status.

### Method
GET

### Response
#### Success Response (200)
- **orientation** (PlineOrientation) - The orientation of the polyline (Clockwise, CounterClockwise, or Open).
```

--------------------------------

### Create a Vector2 using vec2

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/math/fn.vec2.html

Demonstrates the shorthand constructor for initializing a Vector2 with specific x and y coordinates.

```rust
let v = vec2(3.0, 4.0);
assert_eq!(v.x, 3.0);
assert_eq!(v.y, 4.0);
```

--------------------------------

### angle_is_within_sweep_eps

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/math/fn.angle_is_within_sweep_eps.html

Tests if a test_angle is within a sweep_angle starting at a start_angle with fuzzy inclusion.

```APIDOC
## Function: angle_is_within_sweep_eps

### Description
Tests if `test_angle` is within the `sweep_angle` starting at `start_angle`. If `sweep_angle` is positive, the sweep is counter-clockwise; otherwise, it is clockwise. `epsilon` controls the fuzzy inclusion.

### Parameters
- **test_angle** (T) - Required - The angle to test.
- **start_angle** (T) - Required - The starting angle of the sweep.
- **sweep_angle** (T) - Required - The total angle of the sweep.
- **epsilon** (T) - Required - The tolerance for fuzzy inclusion.

### Returns
- **bool** - Returns true if the angle is within the sweep, false otherwise.
```

--------------------------------

### Create a view over a polyline from slice points

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/struct.PlineViewData.html

Demonstrates constructing PlineViewData from specific points on a polyline and creating a view to perform operations like length and extent calculations.

```rust
let mut polyline = Polyline::new_closed();
polyline.add(0.0, 0.0, 0.0);
polyline.add(5.0, 0.0, 0.0);
polyline.add(5.0, 5.0, 0.0);
polyline.add(0.0, 5.0, 0.0);
// construction view data from slice points, view data represents a slice of the source polyline
// starting at (2.5, 0.0) on the first segment (index 0) and ending at (2.5, 5.0) on the third
// segment (index 2)
let view_data =
    PlineViewData::from_slice_points(
        // source polyline
        &polyline,
        // start point
        Vector2::new(2.5, 0.0),
        // segment index start point lies on
        0,
        // end point
        Vector2::new(2.5, 5.0),
        // segment index end point lies on
        2,
        // position equal epsilon
        1e-5).expect("slice not collapsed");

// construct the view (which implements polyline traits) from the view data and source
let view = view_data.view(&polyline);

// we can now use common trait methods on the slice
// note we never had to copy the source polyline
let slice_length = view.path_length();
assert_fuzzy_eq!(view.path_length(), 10.0);
let slice_vertex_count = view.vertex_count();
assert_eq!(slice_vertex_count, 4);
let slice_extents = view.extents().unwrap();
assert_fuzzy_eq!(slice_extents.min_x, 2.5);
assert_fuzzy_eq!(slice_extents.min_y, 0.0);
assert_fuzzy_eq!(slice_extents.max_x, 5.0);
assert_fuzzy_eq!(slice_extents.max_y, 5.0);
```

--------------------------------

### OrAndStitchSelector Constructor

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/internal/pline_boolean.rs.html

Creates a new OrAndStitchSelector instance with specified slice start indices.

```rust
pub fn new(
        start_of_pline2_slices: usize,
        start_of_pline1_overlapping_slices: usize,
        start_of_pline2_overlapping_slices: usize,
    ) -> Self {
        Self {
            start_of_pline2_slices,
            start_of_pline1_overlapping_slices,
            start_of_pline2_overlapping_slices,
        }
    }
```

--------------------------------

### Vector2 Constructors and Basic Operations

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/core/math/vector2.rs.html

Provides methods for creating and manipulating Vector2 instances, including new, zero, scale, dot product, and length calculations.

```APIDOC
## Vector2 Methods

### Description
Provides methods for creating and manipulating Vector2 instances.

### Methods

#### `new(x: T, y: T) -> Self`
Create a new vector with x and y components.

#### `zero() -> Self`
Create a zero vector (x = 0, y = 0).

#### `scale(&self, scale_factor: T) -> Self`
Uniformly scale the vector by `scale_factor`.

#### `dot(&self, other: Self) -> T`
Compute the dot product of two vectors.

#### `perp_dot(&self, other: Self) -> T`
Compute the perpendicular dot product (`self.x * other.y - self.y * other.x`).

#### `length_squared(&self) -> T`
Compute the squared length of the vector.

#### `length(&self) -> T`
Compute the length of the vector.

#### `normalize(&self) -> Self`
Normalize the vector (length = 1).

#### `fuzzy_eq_eps(&self, other: Self, fuzzy_epsilon: T) -> bool`
Fuzzy equal comparison with another vector using `fuzzy_epsilon` given.

#### `fuzzy_eq(&self, other: Self) -> bool`
Fuzzy equal comparison with another vector using T::fuzzy_epsilon().

#### `perp(&self) -> Self`
Create a perpendicular vector.

#### `unit_perp(&self) -> Self`
Create a perpendicular unit vector (length = 1).

#### `rotate_about(&self, origin: Self, angle: T) -> Self`
Rotate this point around an `origin` point by some `angle` in radians.
```

--------------------------------

### FuzzyOrd Trait Documentation

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/core/traits/fuzzy_ord.rs.html

Documentation for the FuzzyOrd trait, including its purpose, methods, and examples.

```APIDOC
## FuzzyOrd Trait

### Description
Trait for fuzzy ordering comparisons with floating point numbers. This trait extends [`FuzzyEq`] to provide fuzzy comparison operations for ordering floating point values. Like fuzzy equality, this accounts for floating point precision issues in greater-than and less-than comparisons.

### Methods

- **`fuzzy_gt_eps(&self, other: Self, fuzzy_epsilon: Self) -> bool`**: Returns `true` if this value is fuzzy greater than the other, using a provided epsilon value.
- **`fuzzy_gt(&self, other: Self) -> bool`**: Fuzzy greater than, using the default epsilon value.
- **`fuzzy_lt_eps(&self, other: Self, fuzzy_epsilon: Self) -> bool`**: Returns `true` if this value is fuzzy less than the other, using a provided epsilon value.
- **`fuzzy_lt(&self, other: Self) -> bool`**: Fuzzy less than, using the default epsilon value.
- **`fuzzy_in_range_eps(&self, min: Self, max: Self, fuzzy_epsilon: Self) -> bool`**: Test if `self` is in range between `min` and `max` with some epsilon for fuzzy comparing.
- **`fuzzy_in_range(&self, min: Self, max: Self) -> bool`**: Same as `fuzzy_in_range_eps` using a default epsilon.

### Examples

```rust
# use cavalier_contours::core::traits::*
let a = 0.1 + 0.2;
let b = 0.3;

// Due to floating point precision, a is actually slightly greater than b
assert!(!(a <= b));

// But fuzzy comparison considers them equal
assert!(a.fuzzy_lt(b));

assert!(0.99f64.fuzzy_in_range_eps(1.0, 2.0, 0.05));
assert!(1.5f64.fuzzy_in_range_eps(1.0, 2.0, 1e-5));
assert!(2.0f64.fuzzy_in_range_eps(1.0, 2.0, 1e-5));
```

### Implementations

- `impl FuzzyOrd for f32`
- `impl FuzzyOrd for f64`
```

--------------------------------

### Polyline Initialization and Userdata Management

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline.rs.html

Methods for creating new Polyline instances and managing associated user-provided metadata.

```rust
impl<T> Default for Polyline<T>
where
    T: Real,
{
    #[inline]
    fn default() -> Self {
        Self::new()
    }
}

impl<T> Polyline<T>
where
    T: Real,
{
    /// Create a new empty [Polyline] with `is_closed` set to false.
    #[inline]
    pub fn new() -> Self {
        Polyline {
            vertex_data: Vec::new(),
            is_closed: false,
            userdata: Vec::new(),
        }
    }

    /// Create a new empty [Polyline] with `is_closed` set to true.
    #[inline]
    pub fn new_closed() -> Self {
        Polyline {
            vertex_data: Vec::new(),
            is_closed: true,
            userdata: Vec::new(),
        }
    }

    #[inline]
    pub fn get_userdata_count(&self) -> usize {
        self.userdata.len()
    }

    #[inline]
    pub fn get_userdata_values(&self) -> impl Iterator<Item = u64> + '_ {
        self.userdata.iter().copied()
    }

    #[inline]
    pub fn set_userdata_values(&mut self, values: impl IntoIterator<Item = u64>) {
        self.userdata.clear();
        self.userdata.extend(values);
    }

    #[inline]
    pub fn add_userdata_values(&mut self, values: impl IntoIterator<Item = u64>) {
        self.userdata.extend(values);
    }
}
```

--------------------------------

### PlineView and PlineViewData Usage

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_view.rs.html

Overview of how to create a PlineViewData instance from a source polyline and convert it into an active PlineView.

```APIDOC
## PlineViewData::from_slice_points

### Description
Creates a PlineViewData instance representing a contiguous subpart of a source polyline defined by start and end points on specific segments.

### Parameters
#### Request Body
- **source** (PlineSource) - Required - The source polyline to slice.
- **start_point** (Vector2) - Required - The starting coordinate of the slice.
- **start_index** (usize) - Required - The segment index where the start point lies.
- **end_point** (Vector2) - Required - The ending coordinate of the slice.
- **end_index** (usize) - Required - The segment index where the end point lies.
- **epsilon** (f64) - Required - The tolerance for position equality checks.

### Response
#### Success Response (200)
- **PlineViewData** (Struct) - The detached view data structure representing the slice.

---

## PlineViewData::view

### Description
Constructs an active PlineView from the detached PlineViewData and a reference to the source polyline.

### Parameters
#### Request Body
- **source** (PlineSource) - Required - The source polyline to borrow for the view.

### Response
#### Success Response (200)
- **PlineView** (Struct) - An active view that implements PlineSource traits.
```

--------------------------------

### Simplify a Circle Defined by Multiple Vertexes

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/traits.rs.html

This example demonstrates simplifying a polyline representing a circle, reducing multiple vertices to just two essential ones. It handles cases where redundant vertexes might be introduced.

```rust
# use cavalier_contours::polyline::*
let bulge = (std::f64::consts::PI / 8.0).tan();
let mut polyline = Polyline::new_closed();
polyline.add(-0.5, 0.0, bulge);
polyline.add(0.0, -0.5, bulge);
// repeat vertex thrown in
polyline.add(0.0, -0.5, bulge);
polyline.add(0.5, 0.0, bulge);
polyline.add(0.0, 0.5, bulge);
let result = polyline.remove_redundant(1e-5).expect("redundant vertexes were removed");
assert_eq!(result.vertex_count(), 2);
assert!(result.is_closed());
assert!(result[0].fuzzy_eq(PlineVertex::new(-0.5, 0.0, 1.0)));
assert!(result[1].fuzzy_eq(PlineVertex::new(0.5, 0.0, 1.0)));
```

--------------------------------

### angle_is_between

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/math/fn.angle_is_between.html

Checks if an angle is between a start and end angle, using default epsilon for fuzzy comparison.

```APIDOC
## angle_is_between

### Description
Checks if `test_angle` is between `start_angle` and `end_angle`. This function uses the default epsilon from the `FuzzyEq` trait for comparison.

### Signature
```rust
pub fn angle_is_between<T>(test_angle: T, start_angle: T, end_angle: T) -> bool
where
    T: Real,
```

### Parameters
- `test_angle` (T): The angle to test.
- `start_angle` (T): The starting angle of the range.
- `end_angle` (T): The ending angle of the range.

### Type Parameters
- `T`: Must implement the `Real` trait, indicating a real number type.
```

--------------------------------

### Create New PlineView

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/struct.PlineView.html

Constructor for PlineView. Use this to create a new view with a given source polyline and view data.

```rust
pub fn new(source: &'a P, data: PlineViewData<P::Num>) -> Self>
```

--------------------------------

### Construct a closed polyline

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/macro.pline_closed.html

Usage example for creating a closed polyline using the pline_closed macro.

```rust
let polyline = pline_closed![(0.0, 1.0, 1.0), (2.0, 0.0, 0.0)];
assert!(polyline.is_closed());
assert_eq!(polyline[0], PlineVertex::new(0.0, 1.0, 1.0));
assert_eq!(polyline[1], PlineVertex::new(2.0, 0.0, 0.0));
```

--------------------------------

### PlineView Struct Methods

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/struct.PlineView.html

Methods for creating and managing a PlineView instance.

```APIDOC
## PlineView::new

### Description
Create a new view with the given source and data.

### Parameters
- **source** (&'a P) - Required - Reference to the source polyline.
- **data** (PlineViewData<P::Num>) - Required - View data used for indexing.

## PlineView::detach

### Description
Consume the view, releasing the borrow on the source polyline and returning the associated view data.
```

--------------------------------

### TryInto Trait Methods

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/enum.BooleanOp.html

Documentation for the conversion methods provided by the TryInto trait.

```APIDOC
## Associated Type: Error

### Description
The type returned in the event of a conversion error.

## fn try_into

### Description
Performs the conversion from the source type to the target type.

### Returns
- **Result<U, <U as TryFrom<T>>::Error>** - A Result containing the converted type or the associated error type.
```

--------------------------------

### Rotate Start Vertex

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/polyline/trait.PlineSource.html

Rotates the vertices of a closed polyline so that a specified point becomes the first vertex.

```APIDOC
## Rotates the vertexes in a closed polyline such that the first vertex’s position is at `point`.

### Description
This method repositions the vertices of a closed polyline without altering its shape. It makes a specified `point` the new starting vertex, using `start_index` to identify the segment containing `point`.

### Method
`rotate_start( &self, start_index: usize, point: Vector2<Self::Num>, pos_equal_eps: Self::Num, ) -> Option<Self::OutputPolyline>`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```rust
let mut polyline = Polyline::new_closed();
polyline.add(0.0, 0.0, 0.0);
polyline.add(1.0, 0.0, 0.0);
polyline.add(1.0, 1.0, 0.0);
polyline.add(0.0, 1.0, 0.0);

let rot = polyline.rotate_start(0, Vector2::new(0.5, 0.0), 1e-5).unwrap();
```

### Response
#### Success Response (200)
Returns a new Polyline with vertices rotated. Returns `None` if the polyline is not closed, has fewer than 2 vertices, or if `start_index` is out of bounds.

#### Response Example
```rust
let mut expected_rot = Polyline::new_closed();
expected_rot.add(0.5, 0.0, 0.0);
expected_rot.add(1.0, 0.0, 0.0);
expected_rot.add(1.0, 1.0, 0.0);
expected_rot.add(0.0, 1.0, 0.0);
expected_rot.add(0.0, 0.0, 0.0);
assert!(rot.fuzzy_eq(&expected_rot));
```
```

--------------------------------

### from_slice_points

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline_view.rs.html

Constructs a view that is contiguous between two points on a source polyline, trimming the start and end as necessary.

```APIDOC
## from_slice_points

### Description
Constructs a view that is contiguous between two points on a source polyline. This method handles the logic for slicing the polyline between a start and end point.

### Parameters
#### Path Parameters
- **source** (P) - Required - The source polyline implementation.
- **start_point** (Vector2<T>) - Required - The starting coordinate.
- **start_index** (usize) - Required - The index to begin from.
- **end_point** (Vector2<T>) - Required - The ending coordinate.
- **end_index** (usize) - Required - The index to end at.
- **pos_equal_eps** (T) - Required - Epsilon value for fuzzy equality checks.

### Response
- **Option<Self>** - Returns the constructed view data or None if construction fails.
```

--------------------------------

### Step 1: Create Offset Loops with Index

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/shape_algorithms/struct.Shape.html

Generates offset polylines for each input polyline and creates a spatial index. Offset loops are separated into counter-clockwise and clockwise collections. This is the first step in the multipolyline offset algorithm.

```rust
pub fn create_offset_loops_with_index(
    &self,
    offset: T,
    options: &ShapeOffsetOptions<T>,
) -> (Vec<OffsetLoop<T>>, Vec<OffsetLoop<T>>, StaticAABB2DIndex<T>)
```

--------------------------------

### Polyline Creation Methods

Source: https://docs.rs/cavalier_contours/0.7.0/src/cavalier_contours/polyline/pline.rs.html

Static methods for creating new Polyline instances from capacity or iterators.

```APIDOC
## Polyline Creation Methods

### Description
Constructors for initializing new Polyline objects.

### Methods
- **with_capacity(capacity: usize, is_closed: bool)**: Creates a new Polyline with pre-allocated capacity.
- **from_iter<I>(iter: I, is_closed: bool)**: Creates a new Polyline by collecting vertices from an iterator.
```

--------------------------------

### FuzzyEq Trait Documentation

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/traits/trait.FuzzyEq.html

Documentation for the FuzzyEq trait, including its purpose, required and provided methods, and examples.

```APIDOC
## Trait FuzzyEq

### Description
Trait for fuzzy equality comparisons with floating point numbers. This trait provides methods for comparing floating point values with a tolerance (epsilon) to account for floating point precision issues. It’s essential for geometric computations where exact equality is rarely achievable due to floating point arithmetic limitations.

### Required Methods

#### fn fuzzy_epsilon() -> Self
Returns the default epsilon value for fuzzy comparisons.

#### fn fuzzy_eq_eps(&self, other: Self, fuzzy_epsilon: Self) -> bool
Returns `true` is this object is approximately equal to the other one, using a provided epsilon value.

#### fn fuzzy_eq_zero_eps(&self, fuzzy_epsilon: Self) -> bool
Returns `true` if this value is approximately equal to zero, using a provided epsilon value.

### Provided Methods

#### fn fuzzy_eq(&self, other: Self) -> bool
Returns `true` is this object is approximately equal to the other one, using the implemented FuzzyEq::fuzzy_epsilon value.

#### fn fuzzy_eq_zero(&self) -> bool
Returns `true` if this value is approximately equal to zero, using the implemented FuzzyEq::fuzzy_epsilon value.

### Examples
```rust
let a = 0.1 + 0.2;
let b = 0.3;

// Direct comparison would fail due to floating point precision
assert_ne!(a, b);

// Fuzzy comparison succeeds
assert!(a.fuzzy_eq(b));
```

### Implementations on Foreign Types

#### impl FuzzyEq for f32

#### impl FuzzyEq for f64

### Dyn Compatibility
This trait is **not** dyn compatible.
```

--------------------------------

### Fuzzy Ordering Example

Source: https://docs.rs/cavalier_contours/0.7.0/cavalier_contours/core/traits/trait.FuzzyOrd.html

Demonstrates how FuzzyOrd can be used to compare floating-point numbers that are expected to be equal but may differ slightly due to precision. It shows that a direct comparison might fail, but a fuzzy comparison succeeds.

```rust
let a = 0.1 + 0.2;
let b = 0.3;

// Due to floating point precision, a is actually slightly greater than b
assert!(!(a <= b));

// But fuzzy comparison considers them equal
assert!(a.fuzzy_lt(b));
```