Enum Scaling 

pub enum Scaling {
    None,
    Proportional,
    Stretch,
}

Whether a form may be drawn at a size other than the one it was designed at.

Scaling is not always right, and the form is the thing that knows. A dial designed against a 1:1 photographic background, a layout whose text must stay a legal minimum size, a panel whose touch targets are already at the smallest a gloved finger can hit — each of those is a form that should be drawn at its design size and centred, not stretched to fit. So it is declared rather than assumed, and the default is the one every form written before this property existed already had.

This is a deployment concern, applied once on the way in. anchors are a design concern, resolved by the tree at every reflow. They are different tools and they compose: a form may use either, both or neither.

let form = Form::parse(r#"form "F" version=1 width=100 height=100 { }"#)?;
assert_eq!(form.scaling(), Scaling::None, "the default is what was always true");

Variants

None

Never scaled. Drawn at its design size, centred in whatever it is given.

Proportional

One factor on both axes — min(target.w / design.w, target.h / design.h) — so nothing distorts, and the leftover is a margin on one axis.

Stretch

A factor per axis, filling the surface. Distorts, and is occasionally exactly what a signage layout wants.

Implementations

impl Scaling

pub const NAMES: &'static [&'static str]

Every one, in the spelling a form file uses.

pub const fn what(self) -> &'static str

assert!(Scaling::None.what().contains("design size"));
assert_ne!(Scaling::Proportional.what(), Scaling::Stretch.what());

One line on what this one does.

Here rather than in the designer for the same reason as FormKind::what: it is a fact about the format, and two copies of a sentence drift.

Trait Implementations

impl Clone for Scaling

fn clone(&self) -> Scaling

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Scaling

impl Debug for Scaling

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

Formats the value using the given formatter.

impl Default for Scaling

fn default() -> Scaling

Returns the “default value” for a type.

impl Eq for Scaling

impl PartialEq for Scaling

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Scaling