Crate emath

Opinionated 2D math library for building GUIs.

Includes vectors, positions, rectangles etc.

Conventions (unless otherwise specified):

• All angles are in radians
• X+ is right and Y+ is down.
• (0,0) is left top.
• Dimension order is always x y

Integrating with other math libraries.

emath does not strive to become a general purpose or all-powerful math library.

For that, use something else (glam, nalgebra, …) and enable the mint feature flag in emath to enable implicit conversion to/from emath.

Feature flags

Modules

align

One- and two-dimensional alignment (Align::Center, Align2::LEFT_TOP etc).

smart_aim

Find “simple” numbers is some range. Used by sliders.

Macros

emath_assert

An assert that is only active when emath is compiled with the extra_asserts feature or with the extra_debug_asserts feature in debug builds.

Structs

Align2

Two-dimension alignment, e.g. Align2::LEFT_TOP.

History

This struct tracks recent values of some time series.

Pos2

A position on screen.

Rangef

Includive range of floats, i.e. min..=max, but more ergonomic than RangeInclusive.

Rect

A rectangular region of space.

RectTransform

Linearly transforms positions from one Rect to another.

Rot2

Represents a rotation in the 2D plane. A rotation of 𝞃/4 = 90° rotates the X axis to the Y axis. Normally a Rot2 is normalized (unit-length). If not, it will also scale vectors.

Vec2

A vector has a direction and length. A Vec2 is often used to represent a size.

Enums

Align

left/center/right or top/center/bottom alignment for e.g. anchors and layouts.

Traits

NumExt

Extends f32, Vec2 etc with at_least and at_most as aliases for max and min.

Numeric

Implemented for all builtin numeric types

One

Helper trait to implement lerp and remap.

Real

Helper trait to implement lerp and remap.

Functions

almost_equal

Return true when arguments are the same within some rounding error.

exponential_smooth_factor

Calculate a lerp-factor for exponential smoothing using a time step.

format_with_decimals_in_range

format_with_minimum_decimals

inverse_lerp

Where in the range is this value? Returns 0-1 if within the range.

lerp

Linear interpolation.

normalized_angle

Wrap angle to [-PI, PI] range.

pos2

pos2(x, y) == Pos2::new(x, y)

remap

Linearly remap a value from one range to another, so that when x == from.start() returns to.start() and when x == from.end() returns to.end().

remap_clamp

Like remap, but also clamps the value so that the returned value is always in the to range.

round_to_decimals

Round a value to the given number of decimal places.

vec2

vec2(x, y) == Vec2::new(x, y)