北京的建设网站公司,php 数据录入网站,优化设计电子课本下载,公众号菜单栏页面模板scale.rs代码是几何变换库euclid中典型的数据结构和方法的例子#xff0c;用于处理二维和三维空间中的缩放变换。
一、scale.rs文件源码
//! A type-checked scaling factor between units.use crate::num::One;use crate::approxord::{max, min};
use crate::{Box2D, Box3D…scale.rs代码是几何变换库euclid中典型的数据结构和方法的例子用于处理二维和三维空间中的缩放变换。
一、scale.rs文件源码
//! A type-checked scaling factor between units.use crate::num::One;use crate::approxord::{max, min};
use crate::{Box2D, Box3D, Point2D, Point3D, Rect, Size2D, Vector2D};use core::cmp::Ordering;
use core::fmt;
use core::hash::{Hash, Hasher};
use core::marker::PhantomData;
use core::ops::{Add, Div, Mul, Sub};#[cfg(feature bytemuck)]
use bytemuck::{Pod, Zeroable};
use num_traits::NumCast;
#[cfg(feature serde)]
use serde::{Deserialize, Serialize};/// A scaling factor between two different units of measurement.
///
/// This is effectively a type-safe float, intended to be used in combination with other types like
/// length::Length to enforce conversion between systems of measurement at compile time.
///
/// Src and Dst represent the units before and after multiplying a value by a Scale. They
/// may be types without values, such as empty enums. For example:
///
/// rust
/// use euclid::Scale;
/// use euclid::Length;
/// enum Mm {};
/// enum Inch {};
///
/// let mm_per_inch: Scalef32, Inch, Mm Scale::new(25.4);
///
/// let one_foot: Lengthf32, Inch Length::new(12.0);
/// let one_foot_in_mm: Lengthf32, Mm one_foot * mm_per_inch;
///
#[repr(C)]
#[cfg_attr(feature serde, derive(Serialize, Deserialize))]
#[cfg_attr(feature serde,serde(bound(serialize T: serde::Serialize,deserialize T: serde::Deserializede))
)]
pub struct ScaleT, Src, Dst(pub T, #[doc(hidden)] pub PhantomData(Src, Dst));implT, Src, Dst ScaleT, Src, Dst {#[inline]pub const fn new(x: T) - Self {Scale(x, PhantomData)}/// 创建标识比例1.0#[inline]pub fn identity() - Selfwhere T: One,{Scale::new(T::one())}/// Returns the given point transformed by this scale.////// # Example////// rust/// use euclid::{Scale, point2};/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.transform_point(point2(42, -42)), point2(420, -420));/// #[inline]pub fn transform_point(self, point: Point2DT, Src) - Point2DT::Output, DstwhereT: Copy Mul,{Point2D::new(point.x * self.0, point.y * self.0)}/// Returns the given point transformed by this scale.#[inline]pub fn transform_point3d(self, point: Point3DT, Src) - Point3DT::Output, DstwhereT: Copy Mul,{Point3D::new(point.x * self.0, point.y * self.0, point.z * self.0)}/// Returns the given vector transformed by this scale.////// # Example////// rust/// use euclid::{Scale, vec2};/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.transform_vector(vec2(42, -42)), vec2(420, -420));/// #[inline]pub fn transform_vector(self, vec: Vector2DT, Src) - Vector2DT::Output, DstwhereT: Copy Mul,{Vector2D::new(vec.x * self.0, vec.y * self.0)}/// Returns the given size transformed by this scale.////// # Example////// rust/// use euclid::{Scale, size2};/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.transform_size(size2(42, -42)), size2(420, -420));/// #[inline]pub fn transform_size(self, size: Size2DT, Src) - Size2DT::Output, DstwhereT: Copy Mul,{Size2D::new(size.width * self.0, size.height * self.0)}/// Returns the given rect transformed by this scale.////// # Example////// rust/// use euclid::{Scale, rect};/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.transform_rect(rect(1, 2, 42, -42)), rect(10, 20, 420, -420));/// #[inline]pub fn transform_rect(self, rect: RectT, Src) - RectT::Output, DstwhereT: Copy Mul,{Rect::new(self.transform_point(rect.origin),self.transform_size(rect.size),)}/// Returns the given box transformed by this scale.#[inline]pub fn transform_box2d(self, b: Box2DT, Src) - Box2DT::Output, DstwhereT: Copy Mul,{Box2D {min: self.transform_point(b.min),max: self.transform_point(b.max),}}/// Returns the given box transformed by this scale.#[inline]pub fn transform_box3d(self, b: Box3DT, Src) - Box3DT::Output, Dstwhere T: Copy Mul,{Box3D {min: self.transform_point3d(b.min),max: self.transform_point3d(b.max),}}/// Returns true if this scale has no effect.////// # Example////// rust/// use euclid::Scale;/// use euclid::num::One;/// enum Mm {};/// enum Cm {};////// let cm_per_mm: Scalef32, Mm, Cm Scale::new(0.1);/// let mm_per_mm: Scalef32, Mm, Mm Scale::new(1.0);////// assert_eq!(cm_per_mm.is_identity(), false);/// assert_eq!(mm_per_mm.is_identity(), true);/// assert_eq!(mm_per_mm, Scale::one());/// #[inline]pub fn is_identity(self) - boolwhere T: PartialEq One,{self.0 T::one()}/// Returns the underlying scalar scale factor.#[inline]pub fn get(self) - T {self.0}/// The inverse Scale (1.0 / self).////// # Example////// rust/// use euclid::Scale;/// enum Mm {};/// enum Cm {};////// let cm_per_mm: Scalef32, Cm, Mm Scale::new(0.1);////// assert_eq!(cm_per_mm.inverse(), Scale::new(10.0));/// pub fn inverse(self) - ScaleT::Output, Dst, SrcwhereT: One Div,{let one: T One::one();Scale::new(one / self.0)}
}implT: PartialOrd, Src, Dst ScaleT, Src, Dst {#[inline]pub fn min(self, other: Self) - Self {Self::new(min(self.0, other.0))}#[inline]pub fn max(self, other: Self) - Self {Self::new(max(self.0, other.0))}/// Returns the point each component of which clamped by corresponding/// components of start and end.////// Shortcut for self.max(start).min(end).#[inline]pub fn clamp(self, start: Self, end: Self) - SelfwhereT: Copy,{self.max(start).min(end)}
}implT: NumCast, Src, Dst ScaleT, Src, Dst {/// Cast from one numeric representation to another, preserving the units.////// # Panics////// If the source value cannot be represented by the target type NewT, then/// method panics. Use try_cast if that must be case.////// # Example////// rust/// use euclid::Scale;/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.cast::f32(), Scale::new(10.0));/// /// That conversion will panic, because i32 not enough to store such big numbers:/// rust,should_panic/// use euclid::Scale;/// enum Mm {};// millimeter 10^-2 meters/// enum Em {};// exameter 10^18 meters////// // Panics/// let to_em: Scalei32, Mm, Em Scale::new(10e20).cast();/// #[inline]pub fn castNewT: NumCast(self) - ScaleNewT, Src, Dst {self.try_cast().unwrap()}/// Fallible cast from one numeric representation to another, preserving the units./// If the source value cannot be represented by the target type NewT, then None/// is returned.////// # Example////// rust/// use euclid::Scale;/// enum Mm {};/// enum Cm {};/// enum Em {};// Exameter 10^18 meters////// let to_mm: Scalei32, Cm, Mm Scale::new(10);/// let to_em: Scalef32, Mm, Em Scale::new(10e20);////// assert_eq!(to_mm.try_cast::f32(), Some(Scale::new(10.0)));/// // Integer to small to store that number/// assert_eq!(to_em.try_cast::i32(), None);/// pub fn try_castNewT: NumCast(self) - OptionScaleNewT, Src, Dst {NumCast::from(self.0).map(Scale::new)}
}#[cfg(feature arbitrary)]
impla, T, Src, Dst arbitrary::Arbitrarya for ScaleT, Src, Dst
whereT: arbitrary::Arbitrarya,
{fn arbitrary(u: mut arbitrary::Unstructureda) - arbitrary::ResultSelf {Ok(Scale::new(arbitrary::Arbitrary::arbitrary(u)?))}
}#[cfg(feature bytemuck)]
unsafe implT: Zeroable, Src, Dst Zeroable for ScaleT, Src, Dst {}#[cfg(feature bytemuck)]
unsafe implT: Pod, Src: static, Dst: static Pod for ScaleT, Src, Dst {}// scale0 * scale1
// (A,B) * (B,C) (A,C)
implT: Mul, A, B, C MulScaleT, B, C for ScaleT, A, B {type Output ScaleT::Output, A, C;#[inline]fn mul(self, other: ScaleT, B, C) - Self::Output {Scale::new(self.0 * other.0)}
}// scale0 scale1
implT: Add, Src, Dst Add for ScaleT, Src, Dst {type Output ScaleT::Output, Src, Dst;#[inline]fn add(self, other: ScaleT, Src, Dst) - Self::Output {Scale::new(self.0 other.0)}
}// scale0 - scale1
implT: Sub, Src, Dst Sub for ScaleT, Src, Dst {type Output ScaleT::Output, Src, Dst;#[inline]fn sub(self, other: ScaleT, Src, Dst) - Self::Output {Scale::new(self.0 - other.0)}
}// FIXME: Switch to derive(PartialEq, Clone) after this Rust issue is fixed:
// https://github.com/rust-lang/rust/issues/26925implT: PartialEq, Src, Dst PartialEq for ScaleT, Src, Dst {fn eq(self, other: ScaleT, Src, Dst) - bool {self.0 other.0}
}implT: Eq, Src, Dst Eq for ScaleT, Src, Dst {}implT: PartialOrd, Src, Dst PartialOrd for ScaleT, Src, Dst {fn partial_cmp(self, other: Self) - OptionOrdering {self.0.partial_cmp(other.0)}
}implT: Ord, Src, Dst Ord for ScaleT, Src, Dst {fn cmp(self, other: Self) - Ordering {self.0.cmp(other.0)}
}implT: Clone, Src, Dst Clone for ScaleT, Src, Dst {fn clone(self) - ScaleT, Src, Dst {Scale::new(self.0.clone())}
}implT: Copy, Src, Dst Copy for ScaleT, Src, Dst {}implT: fmt::Debug, Src, Dst fmt::Debug for ScaleT, Src, Dst {fn fmt(self, f: mut fmt::Formatter) - fmt::Result {self.0.fmt(f)}
}implT: Default, Src, Dst Default for ScaleT, Src, Dst {fn default() - Self {Self::new(T::default())}
}implT: Hash, Src, Dst Hash for ScaleT, Src, Dst {fn hashH: Hasher(self, state: mut H) {self.0.hash(state);}
}implT: One, Src, Dst One for ScaleT, Src, Dst {#[inline]fn one() - Self {Scale::new(T::one())}
}#[cfg(test)]
mod tests {use super::Scale;enum Inch {}enum Cm {}enum Mm {}#[test]fn test_scale() {let mm_per_inch: Scalef32, Inch, Mm Scale::new(25.4);let cm_per_mm: Scalef32, Mm, Cm Scale::new(0.1);let mm_per_cm: Scalef32, Cm, Mm cm_per_mm.inverse();assert_eq!(mm_per_cm.get(), 10.0);let one: Scalef32, Mm, Mm cm_per_mm * mm_per_cm;assert_eq!(one.get(), 1.0);let one: Scalef32, Cm, Cm mm_per_cm * cm_per_mm;assert_eq!(one.get(), 1.0);let cm_per_inch: Scalef32, Inch, Cm mm_per_inch * cm_per_mm;// mm cm cm// ---- x ---- ----// inch mm inchassert_eq!(cm_per_inch, Scale::new(2.54));let a: Scaleisize, Inch, Inch Scale::new(2);let b: Scaleisize, Inch, Inch Scale::new(3);assert_ne!(a, b);assert_eq!(a, a.clone());assert_eq!(a.clone() b.clone(), Scale::new(5));assert_eq!(a - b, Scale::new(-1));// Clampassert_eq!(Scale::identity().clamp(a, b), a);assert_eq!(Scale::new(5).clamp(a, b), b);let a Scale::f32, Inch, Inch::new(2.0);let b Scale::f32, Inch, Inch::new(3.0);let c Scale::f32, Inch, Inch::new(2.5);assert_eq!(c.clamp(a, b), c);}
}二、结构体定义
#[repr(C)]
#[cfg_attr(feature serde, derive(Serialize, Deserialize))]
#[cfg_attr(feature serde,serde(bound(serialize T: serde::Serialize,deserialize T: serde::Deserializede))
)]
pub struct ScaleT, Src, Dst(pub T, #[doc(hidden)] pub PhantomData(Src, Dst));上面代码定义了一个使用Rust语言特性的泛型结构体Scale这个结构体不仅使用了Rust的条件编译指令还考虑了序列化/反序列化的能力如果项目中启用了serde特性。下面是对这段代码的详细解释
#[repr( C )]这个属性指定了结构体应该使用C语言的布局规则。这意味着结构体的内存布局将与C语言中的等效结构相匹配这对于与C语言代码交互或与需要特定内存布局的系统API交互非常有用。#[cfg_attr(feature “serde”, derive(Serialize, Deserialize))]这是条件编译属性的一个示例。如果项目配置了serde特性通常在Cargo.toml文件中通过features部分指定那么将为这个结构体派生Serialize和Deserialize特性。这两个特性来自serde库允许结构体实例被序列化为JSON、RON等格式或从这些格式反序列化。#[cfg_attr(… serde(bound(…)) )]这部分进一步细化了serde特性的条件编译。它指定了当序列化或反序列化时泛型参数T必须满足的条件。具体来说如果正在序列化T必须实现serde::Serialize如果正在反序列化T必须实现serde::Deserializede。这里de是一个生命周期参数它是反序列化过程中使用的表明反序列化操作与特定数据的生命周期相关联。pub struct ScaleT, Src, Dst(pub T, #[doc(hidden)] pub PhantomData(Src, Dst));这是Scale结构体的定义。它是一个泛型结构体有三个类型参数T、Src和Dst。结构体内部包含两个字段
第一个字段是公开的pub T意味着它可以被外部访问。第二个字段是PhantomData(Src, Dst)它被标记为#[doc(hidden)]意味着在生成的文档中这个字段将被隐藏。PhantomData是一个特殊的类型用于在类型系统中表达所有权、借用或生命周期但不占用任何运行时空间。在这里它用于表示Scale结构体与Src和Dst类型有关联尽管这两个类型在运行时并不实际存储任何数据。
总结这段代码定义了一个条件编译支持序列化/反序列化同时遵循C语言内存布局规则的泛型结构体用于在Rust代码中表示某种形式的缩放或转换操作其中T代表缩放或转换的值类型而Src和Dst则用于在类型系统中表达源和目标类型的信息。
三、对应方法
方法源码
implT, Src, Dst ScaleT, Src, Dst {#[inline]pub const fn new(x: T) - Self {Scale(x, PhantomData)}/// 创建标识比例1.0#[inline]pub fn identity() - Selfwhere T: One,{Scale::new(T::one())}/// Returns the given point transformed by this scale.////// # Example////// rust/// use euclid::{Scale, point2};/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.transform_point(point2(42, -42)), point2(420, -420));/// #[inline]pub fn transform_point(self, point: Point2DT, Src) - Point2DT::Output, DstwhereT: Copy Mul,{Point2D::new(point.x * self.0, point.y * self.0)}/// Returns the given point transformed by this scale.#[inline]pub fn transform_point3d(self, point: Point3DT, Src) - Point3DT::Output, DstwhereT: Copy Mul,{Point3D::new(point.x * self.0, point.y * self.0, point.z * self.0)}/// Returns the given vector transformed by this scale.////// # Example////// rust/// use euclid::{Scale, vec2};/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.transform_vector(vec2(42, -42)), vec2(420, -420));/// #[inline]pub fn transform_vector(self, vec: Vector2DT, Src) - Vector2DT::Output, DstwhereT: Copy Mul,{Vector2D::new(vec.x * self.0, vec.y * self.0)}/// Returns the given size transformed by this scale.////// # Example////// rust/// use euclid::{Scale, size2};/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.transform_size(size2(42, -42)), size2(420, -420));/// #[inline]pub fn transform_size(self, size: Size2DT, Src) - Size2DT::Output, DstwhereT: Copy Mul,{Size2D::new(size.width * self.0, size.height * self.0)}/// Returns the given rect transformed by this scale.////// # Example////// rust/// use euclid::{Scale, rect};/// enum Mm {};/// enum Cm {};////// let to_mm: Scalei32, Cm, Mm Scale::new(10);////// assert_eq!(to_mm.transform_rect(rect(1, 2, 42, -42)), rect(10, 20, 420, -420));/// #[inline]pub fn transform_rect(self, rect: RectT, Src) - RectT::Output, DstwhereT: Copy Mul,{Rect::new(self.transform_point(rect.origin),self.transform_size(rect.size),)}/// Returns the given box transformed by this scale.#[inline]pub fn transform_box2d(self, b: Box2DT, Src) - Box2DT::Output, DstwhereT: Copy Mul,{Box2D {min: self.transform_point(b.min),max: self.transform_point(b.max),}}/// Returns the given box transformed by this scale.#[inline]pub fn transform_box3d(self, b: Box3DT, Src) - Box3DT::Output, Dstwhere T: Copy Mul,{Box3D {min: self.transform_point3d(b.min),max: self.transform_point3d(b.max),}}/// Returns true if this scale has no effect.////// # Example////// rust/// use euclid::Scale;/// use euclid::num::One;/// enum Mm {};/// enum Cm {};////// let cm_per_mm: Scalef32, Mm, Cm Scale::new(0.1);/// let mm_per_mm: Scalef32, Mm, Mm Scale::new(1.0);////// assert_eq!(cm_per_mm.is_identity(), false);/// assert_eq!(mm_per_mm.is_identity(), true);/// assert_eq!(mm_per_mm, Scale::one());/// #[inline]pub fn is_identity(self) - boolwhere T: PartialEq One,{self.0 T::one()}/// Returns the underlying scalar scale factor.#[inline]pub fn get(self) - T {self.0}/// The inverse Scale (1.0 / self).////// # Example////// rust/// use euclid::Scale;/// enum Mm {};/// enum Cm {};////// let cm_per_mm: Scalef32, Cm, Mm Scale::new(0.1);////// assert_eq!(cm_per_mm.inverse(), Scale::new(10.0));/// pub fn inverse(self) - ScaleT::Output, Dst, SrcwhereT: One Div,{let one: T One::one();Scale::new(one / self.0)}
}
2、new 方法
这是一个常量函数用于创建一个新的 Scale 实例。它接受一个类型为 T 的参数 x 作为缩放因子。
3、identity 方法
用于创建一个表示没有缩放的 Scale 实例即缩放因子为 1.0。这需要 T 类型实现 One trait该 trait 提供了一个获取类型中“1”的方法。
4、transform_point 方法
用于将二维点Point2DT, Src根据缩放因子变换到新的单位系统Dst。这个方法要求 T 类型实现 Copy 和 Mul traits以便可以复制和乘法操作。
5、transform_point3d 方法
类似于 transform_point但是用于三维点Point3DT, Src。
6、is_identity 方法
检查当前的缩放因子是否为 1.0即是否没有缩放。这要求 T 类型实现 PartialEq 和 One traits。
7、get 方法
返回缩放因子 x。
8、inverse 方法
返回当前缩放的逆缩放即将 1.0 / self.0 作为新的缩放因子。这要求 T 类型实现 One 和 Div traits。
9、min和max方法的实现
min和max方法分别返回两个Scale实例之间较小或较大的那个。它们使用内部存储的值self.0来调用标准库中的min和max函数。
10、clamp方法的实现
clamp方法将当前Scale实例的每个分量限制在start和end指定的范围内。这是通过先对start使用max方法然后对end使用min方法来实现的从而确保结果位于start和end之间。
11、NumCast trait相关的实现
这部分代码被注释掉了似乎原本打算为Scale实现一个与数值类型转换相关的功能允许从一种数值表示转换到另一种但具体的实现被省略了。
12、partial_cmp、cmp方法的实现
partial_cmp方法提供了一个可选的比较结果这在类型T只能部分排序时非常有用例如浮点数与NaN的比较。cmp方法提供了一个确定性的比较结果要求T必须完全可排序实现Ord trait。
13、Clone、Copy trait的实现
为Scale实现了Clone和Copy trait这取决于T是否也实现了这些trait。如果T可以克隆或复制那么ScaleT, Src, Dst也可以。
14、Debug trait的实现
为Scale实现了Debug trait允许其实例使用{:?}格式化时打印调试信息。这依赖于T也实现了Debug trait。
15、Default trait的实现
为Scale实现了Default trait提供了一个默认构造函数它依赖于T也实现了Default trait。
16、Hash trait的实现
为Scale实现了Hash trait允许其实例被哈希。这依赖于T也实现了Hash trait。
17、One trait的实现
为Scale实现了One trait提供了一个单位元素的构造函数即值为1的Scale实例。这依赖于T也实现了One trait。
