Struct Twips

pub struct Twips(/* private fields */);

A type-safe wrapper type documenting where “twips” are used in the SWF format.

A twip is 1/20th of a pixel. Most coordinates in an SWF file are represented in twips.

Use the from_pixels and to_pixels methods to convert to and from pixel values.

Please be careful when using twips for calculations to avoid overflows. As an example, since it takes 20 twips to get 1 pixel, 2,000 pixels are 40,000 twips, or 4*10^4 . If you then have two such numbers, multiplying them as part of calculations yields 16*10^8, which is relatively close to the upper limit of i32 at about 2*10^9.

Implementations

impl Twips

pub const TWIPS_PER_PIXEL: i32 = 20i32

There are 20 twips in a pixel.

pub const ZERO: Self

The Twips object with a value of 0.

Examples

assert_eq!(swf::Twips::ZERO.to_pixels(), 0.0);

pub const ONE_PX: Self

The Twips object with a value of 1 pixel.

Examples

assert_eq!(swf::Twips::ONE_PX.to_pixels(), 1.0);

pub const HALF_PX: Self

The Twips object with a value of 0.5 pixels.

Examples

assert_eq!(swf::Twips::HALF_PX.to_pixels(), 0.5);

pub const fn new(twips: i32) -> Self

Creates a new Twips object. Note that the twips value is in twips, not pixels. Use the from_pixels method to convert from pixel units.

Examples

use swf::Twips;

let twips = Twips::new(40);

pub const fn get(self) -> i32

Returns the number of twips.

Examples

use swf::Twips;

let twips = Twips::new(47);
assert_eq!(twips.get(), 47);

pub fn from_pixels(pixels: f64) -> Self

Converts the given number of pixels into twips.

This may be a lossy conversion; any precision more than a twip (1/20 pixels) is truncated.

Examples

use swf::Twips;

// 40 pixels is equivalent to 800 twips.
let twips = Twips::from_pixels(40.0);
assert_eq!(twips.get(), 800);

// Output is truncated if more precise than a twip (1/20 pixels).
let twips = Twips::from_pixels(40.018);
assert_eq!(twips.get(), 800);

Examples found in repository

examples/writing.rs (line 9)

fn main() {
    let header = Header {
        compression: Compression::Zlib,
        version: 6,
        stage_size: Rectangle {
            x_min: Twips::ZERO,
            x_max: Twips::from_pixels(400.0),
            y_min: Twips::ZERO,
            y_max: Twips::from_pixels(400.0),
        },
        frame_rate: Fixed8::from_f32(60.0),
        num_frames: 1,
    };
    let tags = [
        Tag::SetBackgroundColor(Color {
            r: 255,
            g: 0,
            b: 0,
            a: 255,
        }),
        Tag::ShowFrame,
    ];
    let file = std::fs::File::create("tests/swfs/SimpleRedBackground.swf").unwrap();
    let writer = std::io::BufWriter::new(file);
    swf::write_swf(&header, &tags, writer).unwrap();
}

pub const fn from_pixels_i32(pixels: i32) -> Self

Converts the given number of pixels into twips.

pub fn to_pixels(self) -> f64

Converts this twips value into pixel units.

This is a lossless operation.

Examples

use swf::Twips;

// 800 twips is equivalent to 40 pixels.
let twips = Twips::new(800);
assert_eq!(twips.to_pixels(), 40.0);

// Twips are sub-pixel: 713 twips represent 35.65 pixels.
let twips = Twips::new(713);
assert_eq!(twips.to_pixels(), 35.65);

pub fn trunc_to_pixel(self) -> Self

Truncates this twips to a pixel.

Examples

use swf::Twips;

assert_eq!(Twips::new(23).trunc_to_pixel(), Twips::new(20));
assert_eq!(Twips::new(439).trunc_to_pixel(), Twips::new(420));
assert_eq!(Twips::new(-47).trunc_to_pixel(), Twips::new(-40));

pub fn round_to_pixel_ties_even(self) -> Self

Rounds this twips to the nearest pixel. Rounds half-way cases to the nearest even pixel.

Examples

use swf::Twips;

assert_eq!(Twips::new(29).round_to_pixel_ties_even(), Twips::new(20));
assert_eq!(Twips::new(30).round_to_pixel_ties_even(), Twips::new(40));
assert_eq!(Twips::new(31).round_to_pixel_ties_even(), Twips::new(40));

Trait Implementations

impl Add for Twips

type Output = Twips

The resulting type after applying the + operator.

fn add(self, other: Self) -> Self

Performs the + operation.

impl AddAssign for Twips

fn add_assign(&mut self, other: Self)

Performs the += operation.

impl Clone for Twips

fn clone(&self) -> Twips

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Twips

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Twips

fn default() -> Twips

Returns the “default value” for a type.

impl Display for Twips

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Div<i32> for Twips

type Output = Twips

The resulting type after applying the / operator.

fn div(self, other: i32) -> Self

Performs the / operation.

impl DivAssign<i32> for Twips

fn div_assign(&mut self, other: i32)

Performs the /= operation.

impl Hash for Twips

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

Feeds this value into the given Hasher.

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

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Mul<i32> for Twips

type Output = Twips

The resulting type after applying the * operator.

fn mul(self, other: i32) -> Self

Performs the * operation.

impl MulAssign<i32> for Twips

fn mul_assign(&mut self, other: i32)

Performs the *= operation.

impl Neg for Twips

type Output = Twips

The resulting type after applying the - operator.

fn neg(self) -> Self

Performs the unary - operation.

impl Ord for Twips

fn cmp(&self, other: &Twips) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Twips

fn eq(&self, other: &Twips) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Twips

fn partial_cmp(&self, other: &Twips) -> Option<Ordering>

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

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Sub for Twips

type Output = Twips

The resulting type after applying the - operator.

fn sub(self, other: Self) -> Self

Performs the - operation.

impl SubAssign for Twips

fn sub_assign(&mut self, other: Self)

Performs the -= operation.

impl Copy for Twips

impl Eq for Twips

impl StructuralPartialEq for Twips