Struct kas_core::text::Environment

pub struct Environment {
    pub direction: Direction,
    pub wrap: bool,
    pub align: (Align, Align),
    pub font_id: FontId,
    pub dpem: f32,
    pub bounds: Vec2,
}

Environment in which text is prepared for display

An Environment can be default-constructed (without line-wrapping).

Fields

direction: Direction

Text direction

By default, text direction (LTR or RTL) is automatically detected with full bi-directional text support (Unicode Technical Report #9).

wrap: bool

Line wrapping

By default, this is true and long text lines are wrapped based on the width bounds. If set to false, lines are not wrapped at the width boundary, but explicit line-breaks such as \n still result in new lines.

align: (Align, Align)

Alignment (horiz, vert)

By default, horizontal alignment is left or right depending on the text direction (see Self::direction), and vertical alignment is to the top.

font_id: FontId

Default font

This font is used unless a formatting token (see crate::format) is used.

dpem: f32

Font size: pixels per Em

This is a scaling factor used to convert font sizes, with units pixels/Em. Equivalently, this is the line-height in pixels. See crate::fonts documentation.

To calculate this from text size in Points, use dpem = dpp * pt_size where the dots-per-point is usually dpp = scale_factor * 96.0 / 72.0 on PC platforms, or dpp = 1 on MacOS (or 2 for retina displays).

bounds: Vec2

The available (horizontal and vertical) space

This defaults to infinity (implying no bounds). To enable line-wrapping set at least a horizontal bound. The vertical bound is required for alignment (when aligning to the center or bottom). Glyphs outside of these bounds may not be drawn.

Implementations

impl Environment

pub fn set_font_size(&mut self, pt_size: f32, scale_factor: f32)

Set font size

This is an alternative to setting Self::dpem directly. It is assumed that 72 Points = 1 Inch and the base screen resolution is 96 DPI. (Note: MacOS uses a different definition where 1 Point = 1 Pixel.)

pub fn line_height(&self, font_id: FontId) -> Result<f32, InvalidFontId>

Returns the height of horizontal text

This should be similar to the value of Self::dpem, but depends on the font.

To use “the standard font”, use font_id = Default::default().

impl Environment

pub fn new(dpem: f32) -> Environment

Construct, with explicit font size (pixels per Em)

Trait Implementations

impl Clone for Environment

fn clone(&self) -> Environment

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Environment

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

Formats the value using the given formatter.

impl Default for Environment

fn default() -> Environment

Returns the “default value” for a type.

impl PartialEq for Environment

fn eq(&self, other: &Environment) -> 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 Environment

impl StructuralPartialEq for Environment