Struct turtle::Speed[−][src]

pub struct Speed(_);

Represents both the movement and rotation speed of the turtle.

Creating Speeds

You can create a Speed value by converting either strings or numbers.

// This value is of type `Speed` and it is converted from an `i32`
let speed: Speed = 1.into();

// This value is of type `Speed` and it is converted from a `&str`
let slowest_speed: Speed = "slowest".into();

There is no need to call .into() when passing a speed into the set_speed method. See the set_speed method for more information about how that works.

let mut turtle = Turtle::new();
turtle.set_speed(22); // Same as `turtle.set_speed(22.into())`

The minimum speed value is 1 and the maximum speed value (currently) is 25.

Trying to set the speed to a value out of that range will cause a panic.

let mut turtle = Turtle::new();
turtle.set_speed(26); // panic!

While the minimum speed will not change, the maximum speed may grow larger if the need arises. That is why we chose to panic for invalid speeds instead of defaulting to another value.

String Conversion

Strings are converted as follows:

String Value
"slowest" 1
"slower" 5
"slow" 8
"normal" 10
"fast" 12
"faster" 15
"instant" see below

You can use strings to create Speed values in the same way numbers were used above. Each of the following is an equivalent way to set the speed to 5:

turtle.set_speed(5);
turtle.set_speed("slower");
turtle.set_speed(Speed::from(5)); // Not recommended!
turtle.set_speed(Speed::from("slower")); // Not recommended!

Instant

There is one special speed value "instant" which makes it so that movement and rotation are not animated at all. Instead, the turtle immediately moves and rotates to the position that you directed it to. It will still draw along the way if its pen is down.

let mut turtle = Turtle::new();
turtle.set_speed("instant");
turtle.forward(100.0); // A line will be drawn instantly!

Comparing Speed Values

Speed values can be compared for equality with i32 values. This is a little more convenient than converting the i32 to Speed every time you want to make a comparison.

let speed: Speed = 1.into();
// Speed values can be compared to integers
assert_eq!(speed, 1);
// This is equivalent to the following
assert_eq!(speed, Speed::from(1));

// This value is of type `Speed` and it is converted from a `&str`
let speed: Speed = "slowest".into();
// Speed values can be compared to other speed values
assert_eq!(speed, Speed::from("slowest"));
// This is equivalent to the following since the slowest speed is 1
assert_eq!(speed, 1);

You can use the <, <=, ==, >=, > with Speed values and i32 values (or other Speed values).

let turtle = Turtle::new();
let speed = turtle.speed();
if speed == 12 && speed >= 5 && speed < Speed::instant() {
println!("Super fast!!");
}
// This is equivalent, but requires more typing
if speed == Speed::from(12) && speed >= Speed::from(5) && speed < Speed::from("instant") {
println!("Super fast!!");
}

Notice that you can compare Speed values to numeric values, but not the other way around.

let speed: Speed = 7.into();
if 8 > speed { // This doesn't make sense and won't compile!
// ...
}

To check if a speed is instant, use the is_instant() method or compare the speed to Speed::instant().

let speed = Speed::instant();
if speed.is_instant() {
println!("Instant!!");
}

Methods

impl Speed[src]

pub fn instant() -> Self[src]

Returns the speed value that will make the turtle move and rotate instantly. This means that instead of the turtle's movements being animated, it will directly move to wherever you direct it to go.

let mut turtle = Turtle::new();
turtle.set_speed(Speed::instant());
turtle.forward(100.0); // A line will be drawn instantly!

Whenever possible, you should prefer to use the string "instant" instead of calling this method.

turtle.set_speed("instant"); // equivalent to typing `Speed::instant()`

pub fn is_instant(self) -> bool[src]

Returns true if this speed is the same as Speed::instant()

use turtle::{Speed};
let speed: Speed = "instant".into();
assert!(speed.is_instant());

let speed = Speed::instant();
assert!(speed.is_instant());

Trait Implementations

impl Debug for Speed[src]

fn fmt(&self, f: &mut Formatter) -> Result[src]

Formats the value using the given formatter. Read more

impl Clone for Speed[src]

fn clone(&self) -> Speed[src]

Returns a copy of the value. Read more

fn clone_from(&mut self, source: &Self)1.0.0[src]

Performs copy-assignment from source. Read more

impl PartialEq for Speed[src]

fn eq(&self, other: &Speed) -> bool[src]

This method tests for self and other values to be equal, and is used by ==. Read more

fn ne(&self, other: &Speed) -> bool[src]

This method tests for !=.

impl PartialOrd for Speed[src]

fn partial_cmp(&self, other: &Speed) -> Option<Ordering>[src]

This method returns an ordering between self and other values if one exists. Read more

fn lt(&self, other: &Speed) -> bool[src]

This method tests less than (for self and other) and is used by the < operator. Read more

fn le(&self, other: &Speed) -> bool[src]

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

fn gt(&self, other: &Speed) -> bool[src]

This method tests greater than (for self and other) and is used by the > operator. Read more

fn ge(&self, other: &Speed) -> bool[src]

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

impl Ord for Speed[src]

fn cmp(&self, other: &Speed) -> Ordering[src]

This method returns an Ordering between self and other. Read more

fn max(self, other: Self) -> Self1.21.0[src]

Compares and returns the maximum of two values. Read more

fn min(self, other: Self) -> Self1.21.0[src]

Compares and returns the minimum of two values. Read more

impl Hash for Speed[src]

fn hash<__H: Hasher>(&self, state: &mut __H)[src]

Feeds this value into the given [Hasher]. Read more

fn hash_slice<H>(data: &[Self], state: &mut H) where    H: Hasher, 1.3.0[src]

Feeds a slice of this type into the given [Hasher]. Read more

impl Display for Speed[src]

fn fmt(&self, f: &mut Formatter) -> Result[src]

Formats the value using the given formatter. Read more

impl PartialEq<i32> for Speed[src]

fn eq(&self, other: &i32) -> bool[src]

This method tests for self and other values to be equal, and is used by ==. Read more

fn ne(&self, other: &Rhs) -> bool1.0.0[src]

This method tests for !=.

impl PartialOrd<i32> for Speed[src]

fn partial_cmp(&self, other: &i32) -> Option<Ordering>[src]

This method returns an ordering between self and other values if one exists. Read more

fn lt(&self, other: &Rhs) -> bool1.0.0[src]

This method tests less than (for self and other) and is used by the < operator. Read more

fn le(&self, other: &Rhs) -> bool1.0.0[src]

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

fn gt(&self, other: &Rhs) -> bool1.0.0[src]

This method tests greater than (for self and other) and is used by the > operator. Read more

fn ge(&self, other: &Rhs) -> bool1.0.0[src]

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

impl Distribution<Speed> for Standard[src]

fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Speed[src]

Generate a random value of T, using rng as the source of randomness.

ⓘImportant traits for DistIter<'a, D, R, T>Important traits for DistIter<'a, D, R, T> impl<'a, D, R, T> Iterator for DistIter<'a, D, R, T> where    D: Distribution<T>,    R: Rng + 'a,  type Item = T;fn sample_iter<R>(&'a self, rng: &'a mut R) -> DistIter<'a, Self, R, T> where    R: Rng, [src]

Create an iterator that generates random values of T, using rng as the source of randomness. Read more

impl<'a> From<&'a str> for Speed[src]

fn from(s: &'a str) -> Self[src]

Performs the conversion.

impl From<i32> for Speed[src]

fn from(n: i32) -> Self[src]

Performs the conversion.

impl From<f64> for Speed[src]

fn from(n: f64) -> Self[src]

Performs the conversion.