pub trait Shape: Sized {
type PathElementsIter<'iter>: Iterator<Item = PathEl> + 'iter
where Self: 'iter;
Show 14 methods
// Required methods
fn path_elements(&self, tolerance: f64) -> Self::PathElementsIter<'_>;
fn area(&self) -> f64;
fn perimeter(&self, accuracy: f64) -> f64;
fn winding(&self, pt: Point) -> i32;
fn bounding_box(&self) -> Rect;
// Provided methods
fn to_path(&self, tolerance: f64) -> BezPath { ... }
fn into_path(self, tolerance: f64) -> BezPath { ... }
fn path_segments(
&self,
tolerance: f64
) -> Segments<Self::PathElementsIter<'_>> ⓘ { ... }
fn contains(&self, pt: Point) -> bool { ... }
fn as_line(&self) -> Option<Line> { ... }
fn as_rect(&self) -> Option<Rect> { ... }
fn as_rounded_rect(&self) -> Option<RoundedRect> { ... }
fn as_circle(&self) -> Option<Circle> { ... }
fn as_path_slice(&self) -> Option<&[PathEl]> { ... }
}Expand description
A generic trait for open and closed shapes.
This trait provides conversion from shapes to BezPaths, as well as
general geometry functionality like computing area, bounding_boxes,
and winding number.
Required Associated Types§
sourcetype PathElementsIter<'iter>: Iterator<Item = PathEl> + 'iter
where
Self: 'iter
type PathElementsIter<'iter>: Iterator<Item = PathEl> + 'iter where Self: 'iter
The iterator returned by the path_elements method.
Required Methods§
sourcefn path_elements(&self, tolerance: f64) -> Self::PathElementsIter<'_>
fn path_elements(&self, tolerance: f64) -> Self::PathElementsIter<'_>
Returns an iterator over this shape expressed as PathEls;
that is, as Bézier path elements.
All shapes can be represented as Béziers, but in many situations
(such as when interfacing with a platform drawing API) there are more
efficient native types for specific concrete shapes. In this case,
the user should exhaust the as_ methods (as_rect, as_line, etc)
before converting to a BezPath, as those are likely to be more
efficient.
In many cases, shapes are able to iterate their elements without
allocating; however creating a BezPath object always allocates.
If you need an owned BezPath you can use to_path instead.
§Tolerance
The tolerance parameter controls the accuracy of
conversion of geometric primitives to Bézier curves, as
curves such as circles cannot be represented exactly but
only approximated. For drawing as in UI elements, a value
of 0.1 is appropriate, as it is unlikely to be visible to
the eye. For scientific applications, a smaller value
might be appropriate. Note that in general the number of
cubic Bézier segments scales as tolerance ^ (-1/6).
sourcefn area(&self) -> f64
fn area(&self) -> f64
Signed area.
This method only produces meaningful results with closed shapes.
The convention for positive area is that y increases when x is positive. Thus, it is clockwise when down is increasing y (the usual convention for graphics), and anticlockwise when up is increasing y (the usual convention for math).
sourcefn winding(&self, pt: Point) -> i32
fn winding(&self, pt: Point) -> i32
The winding number of a point.
This method only produces meaningful results with closed shapes.
The sign of the winding number is consistent with that of area,
meaning it is +1 when the point is inside a positive area shape
and -1 when it is inside a negative area shape. Of course, greater
magnitude values are also possible when the shape is more complex.
sourcefn bounding_box(&self) -> Rect
fn bounding_box(&self) -> Rect
The smallest rectangle that encloses the shape.
Provided Methods§
sourcefn to_path(&self, tolerance: f64) -> BezPath
fn to_path(&self, tolerance: f64) -> BezPath
Convert to a Bézier path.
This always allocates. It is appropriate when both the source shape and the resulting path are to be retained.
If you only need to iterate the elements (such as to convert them to
drawing commands for a given 2D graphics API) you should prefer
path_elements, which can avoid allocating where possible.
The tolerance parameter is the same as for path_elements.
sourcefn into_path(self, tolerance: f64) -> BezPath
fn into_path(self, tolerance: f64) -> BezPath
Convert into a Bézier path.
This allocates in the general case, but is zero-cost if the
shape is already a BezPath.
The tolerance parameter is the same as for path_elements().
sourcefn path_segments(&self, tolerance: f64) -> Segments<Self::PathElementsIter<'_>> ⓘ
fn path_segments(&self, tolerance: f64) -> Segments<Self::PathElementsIter<'_>> ⓘ
Returns an iterator over this shape expressed as Bézier path
segments (PathSegs).
The allocation behaviour and tolerance parameter are the
same as for path_elements()
sourcefn contains(&self, pt: Point) -> bool
fn contains(&self, pt: Point) -> bool
Returns true if the Point is inside this shape.
This is only meaningful for closed shapes.
sourcefn as_rounded_rect(&self) -> Option<RoundedRect>
fn as_rounded_rect(&self) -> Option<RoundedRect>
If the shape is a rounded rectangle, make it available.
sourcefn as_path_slice(&self) -> Option<&[PathEl]>
fn as_path_slice(&self) -> Option<&[PathEl]>
If the shape is stored as a slice of path elements, make that available.
Note: when GAT’s land, a method like path_elements would be
able to iterate through the slice with no extra allocation,
without making any assumption that storage is contiguous.
Object Safety§
Implementations on Foreign Types§
source§impl<'a> Shape for &'a [PathEl]
impl<'a> Shape for &'a [PathEl]
Implements Shape for a slice of PathEl, provided that the first element of the slice is
not a PathEl::ClosePath. If it is, several of these functions will panic.
If the slice starts with LineTo, QuadTo, or CurveTo, it will be treated as a MoveTo.
type PathElementsIter<'iter> = Copied<Iter<'a, PathEl>> where 'a: 'iter
fn path_elements(&self, _tolerance: f64) -> Self::PathElementsIter<'_>
fn to_path(&self, _tolerance: f64) -> BezPath
fn perimeter(&self, accuracy: f64) -> f64
fn bounding_box(&self) -> Rect
fn as_path_slice(&self) -> Option<&[PathEl]>
source§impl<'a, T: Shape> Shape for &'a T
impl<'a, T: Shape> Shape for &'a T
Blanket implementation so impl Shape will accept owned or reference.
type PathElementsIter<'iter> = <T as Shape>::PathElementsIter<'iter> where T: 'iter, 'a: 'iter
fn path_elements(&self, tolerance: f64) -> Self::PathElementsIter<'_>
fn to_path(&self, tolerance: f64) -> BezPath
fn path_segments(&self, tolerance: f64) -> Segments<Self::PathElementsIter<'_>> ⓘ
fn area(&self) -> f64
fn perimeter(&self, accuracy: f64) -> f64
fn winding(&self, pt: Point) -> i32
fn bounding_box(&self) -> Rect
fn as_line(&self) -> Option<Line>
fn as_rect(&self) -> Option<Rect>
fn as_rounded_rect(&self) -> Option<RoundedRect>
fn as_circle(&self) -> Option<Circle>
fn as_path_slice(&self) -> Option<&[PathEl]>
source§impl<const N: usize> Shape for [PathEl; N]
impl<const N: usize> Shape for [PathEl; N]
Implements Shape for an array of PathEl, provided that the first element of the array is
not a PathEl::ClosePath. If it is, several of these functions will panic.
If the array starts with LineTo, QuadTo, or CurveTo, it will be treated as a MoveTo.