Struct druid::Scale

pub struct Scale { /* private fields */ }

Coordinate scaling between pixels and display points.

This holds the platform scale factors.

Pixels and Display Points

A pixel (px) represents the smallest controllable area of color on the platform. A display point (dp) is a resolution independent logical unit. When developing your application you should primarily be thinking in display points. These display points will be automatically converted into pixels under the hood. One pixel is equal to one display point when the platform scale factor is 1.0.

Read more about pixels and display points in the Druid book.

Converting with Scale

To translate coordinates between pixels and display points you should use one of the helper conversion methods of Scale or for manual conversion x / y.

Scale is designed for responsive applications, including responding to platform scale changes. The platform scale can change quickly, e.g. when moving a window from one monitor to another.

A copy of Scale will be stale as soon as the platform scale changes.

Implementations

impl Scale

pub fn new(x: f64, y: f64) -> Scale

Create a new Scale based on the specified axis factors.

Units: none (scale relative to “standard” scale)

pub fn x(self) -> f64

Returns the x axis scale factor.

pub fn y(self) -> f64

Returns the y axis scale factor.

pub fn px_to_dp_x<T>(self, x: T) -> f64where
    T: Into<f64>,

Converts from pixels into display points, using the x axis scale factor.

pub fn px_to_dp_y<T>(self, y: T) -> f64where
    T: Into<f64>,

Converts from pixels into display points, using the y axis scale factor.

pub fn px_to_dp_xy<T>(self, x: T, y: T) -> (f64, f64)where
    T: Into<f64>,

Converts from pixels into display points, using the x axis scale factor for x and the y axis scale factor for y.

Trait Implementations

impl Clone for Scale

fn clone(&self) -> Scale

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Data for Scale

fn same(&self, other: &Self) -> bool

Determine whether two values are the same.

impl Debug for Scale

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

Formats the value using the given formatter.

impl Default for Scale

fn default() -> Scale

Returns the “default value” for a type.

impl PartialEq<Scale> for Scale

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

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

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

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

impl Copy for Scale

impl StructuralPartialEq for Scale