Struct kas_text::Environment

pub struct Environment {
    pub flags: EnvFlags,
    pub dir: Direction,
    pub font_id: FontId,
    pub dpp: f32,
    pub pt_size: f32,
    pub bounds: Vec2,
    pub align: (Align, Align),
}

Environment in which text is prepared for display

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

Fields

flags: EnvFlags

Flags enabling/disabling certain features

Bidirectional text

If enabled, right-to-left text embedded within left-to-right text and LTR within RTL will be re-ordered according to the Unicode Bidirectional Algorithm (Unicode Technical Report #9).

If disabled, the base paragraph direction may be LTR or RTL depending on Environment::dir, but embedded text is not re-ordered.

Default value: true. This should normally be enabled unless there is a specific reason to disable it.

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.

dir: Direction

Default text direction

Usually this may be left to its default value of Direction::Auto. If bidi == true, this parameter sets the “paragraph embedding level” (whose main affect is on lines without strongly-directional characters). If bidi == false this directly sets the line direction, unless dir == Auto, in which case direction is auto-detected.

font_id: FontId

Default font

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

dpp: f32

Pixels-per-point

This is a scaling factor used to convert font sizes (in points) to a size in pixels (dots). Units are pixels/point. See crate::fonts documentation.

Default value: 96.0 / 72.0

pt_size: f32

Default font size in points

We use “point sizes” (Points per Em), since this is a widely used measure of font size. See crate::fonts module documentation.

Default value: 11.0

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 centre or bottom). Glyphs outside of these bounds may not be drawn.

align: (Align, Align)

Alignment (horiz, vert)

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

Implementations

impl Environment

pub fn height(&self, font_id: FontId) -> f32

Returns the height of standard horizontal text

This depends on the pt_size and dpp fields.

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

impl Environment

pub fn new(dpp: f32, pt_size: f32) -> Self

Construct, with explicit font size

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

Formats the value using the given formatter.

impl Default for Environment

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq<Environment> 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: &Environment) -> bool

This method tests for !=.

impl StructuralPartialEq for Environment