Crate frus_core

Expand description

frus-core — the fundamental types shared by the whole framework.

This crate holds no logic: only data types (geometry, colour) with no dependency on rendering or on any platform. It is the common foundation for frus-gpu, frus-layout and the rest, which keeps those layers from duplicating types or coupling to one another.

Re-exports§

pub use animation::Animatable;
pub use animation::Animation;
pub use animation::AnimationController;
pub use animation::BouncingScrollSimulation;
pub use animation::ClampedSimulation;
pub use animation::ClampingScrollSimulation;
pub use animation::Curve;
pub use animation::Curved;
pub use animation::FrictionSimulation;
pub use animation::Lerp;
pub use animation::PolynomialFit;
pub use animation::Simulation;
pub use animation::SpringDescription;
pub use animation::SpringSimulation;
pub use animation::Status;
pub use animation::Tolerance;
pub use animation::Tween;
pub use animation::TweenSequence;
pub use animation::Velocity;
pub use animation::VelocityEstimate;
pub use animation::VelocityStrategy;
pub use animation::VelocityTracker;
pub use animation::BOUNCING_DRAG;
pub use animation::BOUNCING_FLING_WEIGHTS;
pub use animation::CLAMPING_FRICTION;
pub use animation::DESKTOP_FLING_WEIGHTS;
pub use animation::MAX_SPRING_TRANSFER_VELOCITY;
pub use platform::debug_default_target_platform_override;
pub use platform::default_target_platform;
pub use platform::set_debug_default_target_platform_override;
pub use platform::Platform;
pub use platform::TargetPlatform;
pub use platform::IS_WEB;

Modules§

animation: Animation: the physics and kinematics layer shared by the whole framework, with no dependency on rendering or on any platform.

Structs§

Affine: A 2D affine transform (a 2×3 matrix). A point (x, y) becomes (a·x + c·y + e, b·x + d·y + f): a 2×2 linear part [[a, c], [b, d]] (scale, rotation, shear) plus a translation (e, f).
Alignment: Where to place a child inside its containing box: two continuous fractions in [-1, 1]. x = -1 hugs the left, 0 centres, +1 hugs the right; y = -1 is the top, +1 the bottom. Being continuous, it interpolates (crate::Lerp): a Tween<Alignment> slides a child from one anchor to another. The nine usual anchors are provided as constants (Alignment::CENTER, Alignment::TOP_LEFT, and so on).
AlignmentDirectional: A directional anchor: the horizontal axis is expressed start → end rather than left → right. x_start = -1 hugs the start edge (left in LTR, right in RTL), +1 the end edge. Resolved into a physical Alignment at render time from the reading direction — the anchor follows the text without the caller ever testing which way it runs.
Backdrop: A filter over what has already been painted underneath a layer: the frosted glass a sheet, a bar or a dialog sits on.
Border: A box’s border, side by side — the reference’s Border (box_border.dart:431): each of the four sides its own colour and width.
BorderDirectional: A box’s border, by the line’s start and end — the reference’s BorderDirectional (box_border.dart:799): the start side is the left in a left-to-right script and the right in a right-to-left one.
BorderRadius: Corner radii, per corner (logical px). From<f32> covers the uniform case: anywhere a radius is expected, a plain 10.0 still works.
BorderRadiusDirectional: A corner radius named by the reading direction rather than by the wall (border_radius.dart:621).
BorderSide: One edge of a shape: what colour it is drawn in and how thick it is (border_side.dart).
BoxDecoration: The complete decoration of a box — the reference’s BoxDecoration (box_decoration.dart:81).
BoxShadow: A soft drop shadow.
Color: An RGBA colour. Components lie in [0.0, 1.0].
Colors: The named colours of the material palette, as plain Color constants.
DecodeSize: The size an image is decoded at, in physical pixels: the full size of the file, or a smaller one that the place it is shown at needs.
DecorationImage: A picture painted as a box’s background — the reference’s DecorationImage.
FittedSizes: The two sizes a fit settles on — the reference’s FittedSizes.
GradientRamp: A gradient with any number of stops, for a path: its shape, its colours, what it does past its ends, and where it sits.
Hct: A colour in HCT: CAM16 hue (degrees), CAM16 chroma, and L* tone.
ImageData: An image’s pixels: 8-bit RGBA, sRGB, row by row from the top-left corner (width * height * 4 bytes). Immutable once built.
ImagePiece: One part of a picture drawn somewhere: where, and which part, in 0..1 of the picture (a negative width walks it backwards, which is how a picture is mirrored).
Insets: Insets — padding or margin — per side, in logical pixels.
InsetsDirectional: Directional insets: start/end instead of left/right. In LTR, start is the left; in RTL it is the right. Resolved into concrete Insets at layout time.
LayerFilter: Everything a layer applies to its own pixels at compositing time. All three are optional and independent; LayerFilter::is_none is the fast path the renderer takes when nothing is asked for, which is nearly always.
LayerTransform: The transform applied to a layer (Primitive::Layer) at compositing time: an arbitrary Affine (translation, per-axis scale, rotation, or any composition of them) in screen pixels. The layer is first rendered flat into a texture, as with group opacity, then composited transformed — so a single pass transforms a whole subtree (rects, text, images) without touching any individual primitive’s shaders.
LinearGradient: A gradient along a line, from begin to end (gradient.dart’s LinearGradient). Unset, from the centre of the left side to the centre of the right.
MaterialColor: A colour ramp: one hue in numbered steps, from the palest (50) to the darkest (900), plus the primary step the family is named after.
Path: A vector path: a sequence of PathVerb. Built in builder style (chainable), and consumed at render time.
Platform: Facts about the machine the application runs on, fixed for the life of the process. Unlike TargetPlatform, nothing overrides them.
Point: A 2D point.
RadialGradient: A gradient round a centre (gradient.dart’s RadialGradient): the first colour at center, the last on the circle radius round it. With a focal point, the first colour is on the circle focal_radius round that point instead, and the gradient runs between the two circles.
Rect: An axis-aligned rectangle, in logical pixels.
ResolvedTextStyle: A TextStyle with every question answered: what to measure with, and what to draw.
Scene: A 2D scene: the declarative description of what to draw.
SemanticsProperties: A widget’s resolved semantic annotation, for accessibility.
ShaderMask: A colour blended over a subtree — the ShaderMask widget’s payload.
Size: A 2D size (width × height).
Stroke: An outline (the line a path is drawn with): colour, width, in pixels, and how its ends are drawn.
SweepGradient: A gradient turning round a centre (gradient.dart’s SweepGradient): from start_angle to end_angle, in radians clockwise from the right.
TextBlock: The box a block of text is laid out in: how wide it is, whether the text wraps at that width, and where the lines sit inside it. See Scene::text_block.
TextDecoration: A text’s decoration lines, which combine with one another. They have no effect on measurement: the text’s geometry does not change, and the lines are drawn by the backend from the baseline metrics.
TextRun: A text run ready to render: a fragment plus its typographic attributes and colour, all resolved — nothing left to inherit.
TextScaleGuard: Puts back the scale that was in force before install_text_scale, when dropped — including while a panic unwinds, so one bad frame cannot leave a stale scale installed for every frame after it.
TextSpan: A rich-text tree: each node carries a fragment of text, partial style overrides — whatever is unspecified inherits from the parent, so a .bold() child keeps its parent’s size — and children of its own.
TextStyle: The typographic attributes of a single line of text — every field optional.
TonalPalette: A tonal palette: one hue and chroma spread across the tone scale. tone(90) is very light, tone(10) very dark, and both read as one colour.
WindowInsets: The window insets, split by nature: padding is the area permanently taken by the system (status and navigation bars, the notch — all static), while view_insets is the area covered by transient UI, chiefly the soft keyboard. Avoiding the keyboard means keeping content clear of WindowInsets::safe.

Enums§

AlignmentGeometry: A resolvable anchor — either physical (Alignment) or directional (AlignmentDirectional). A widget accepts either one, through Into, and resolves it against the reading direction at render time.
BlendMode: How a source colour is combined with the destination underneath it.
BlurStyle: Which side of a shape a blur keeps (milestone 645), the reference’s BlurStyle.
BoxBorder: A box’s border, by its physical sides or by the line’s start and end.
BoxFit: How an image is fitted into its destination box — the same set of modes as the CSS object-fit property.
BoxShape: The shape a box decoration paints — the reference’s BoxShape (box_border.dart:26).
ClipShape: The clip shape of a Primitive::Layer, inscribed in its clip rectangle. Compositing multiplies the layer’s alpha by the shape’s coverage, with antialiased edges. This is the building block of the ClipRRect, ClipOval and ClipPath widgets.
ColorFilter: A function applied to every pixel of a subtree, independently of its neighbours: greyscale, a tint, a contrast curve.
Fetched: What is known about an image that has to be fetched before it can be shown.
FillRule: Which points a filled path covers, where its contours cross or nest.
FontFamily: A font family, as a style names it.
FontWeight: Font weight — a useful subset, mapped onto the CSS/OpenType weights.
FractionalMask: A MaskShader written in fractions of the box it covers — (0, 0) the top-left corner, (1, 1) the bottom-right.
Gradient: Any of the three.
ImageFilter: A filter that treats the subtree as an image, so a pixel’s result depends on its neighbours: a blur, a spread, a shrink.
ImageRepeat: How a picture fills the room its fit leaves: once, or repeated across, down, or both — the reference’s ImageRepeat.
InsetsGeometry: Insets that are either physical (Insets) or directional (InsetsDirectional). A widget accepts either one — or one number for all four sides — through Into, and resolves it against the reading direction at layout time.
MaskShader: The colour a ShaderMask blends over its subtree, as a two-stop fade.
Orientation: Display orientation, derived from the width-to-height ratio.
PathGradient: How a path’s fill fades: along a line, or outwards from a centre.
PathVerb: A single drawing command.
Primitive: A drawing primitive.
RampShape: Where a GradientRamp’s colours run.
Role: An element’s semantic role (a subset aligned on AccessKit/ARIA roles: what a screen reader announces).
ShapeBorder: What shape a box is (shape_border.dart), and the edge around it.
SizeClass: A display-width band.
StrokeCap: How an open line ends — the reference’s StrokeCap (milestone 630).
TargetPlatform: The platforms whose conventions a widget can follow.
TextAlign: How the lines of a piece of text are aligned inside the box it was given.
TextDirection: The reading direction of text and layout. An ambient context: in RTL, rows, alignment and directional insets all flip horizontally.
TextOverflow: What becomes of text that does not fit the box it was given.
TileMode: What a gradient does past its ends (dart:ui’s TileMode).
Toggled: The checked state of a toggleable control (checkbox, switch, radio).

Constants§

DEFAULT_IMAGE_CACHE_BYTES: The default ceiling on decoded network images held in memory: the reference’s own figure.
DEFAULT_LINE_HEIGHT: The line height a style that says nothing gets, as a multiple of the font size.
DEFAULT_TEXT_SIZE: The font size a text ends up at when nothing anywhere in the chain named one.
IS_WEB: Whether this binary runs in a browser. A constant: a build is for the web or not.
MAX_IMAGE_TILES: The most tiles one repeated picture draws. A one-pixel pattern repeated over a large box would otherwise be millions of draws; past this, the rest of the box stays empty.

Functions§

apply_box_fit: Fits input into output by fit — the reference’s applyBoxFit.
cached: Resolves bytes to pixels once, returning the same handle on every later call.
cached_at: cached, at a DecodeSize: the same bytes decoded at two sizes are two entries, and load is the one that decodes at size.
debug_default_target_platform_override: The override of default_target_platform, if one is set.
decoded_at: cached_at, decoding on a background thread when in_the_background says so: Fetched::Loading until the pixels are there, and the frames keep coming meanwhile (images_in_flight counts it).
default_target_platform: The platform whose conventions an application follows unless its theme says otherwise: the debug override if one is set, else the browser’s operating system on the web, else the platform the binary was built for.
fetched: What is known about the image at url, starting the fetch if this is the first ask.
fetched_at: fetched, at a DecodeSize: decode is handed the size along with the bytes.
fits: The rule for anything that measures itself: report a whole number of pixels, rounded up.
forget_cached_images: Empties the store. For tests that want a decode to happen again; an application has no reason to call it, since the entries are one per embedded asset and size, and bounded by how many the binary carries. trim_image_caches is the one for memory.
forget_fetched_images: Forgets every fetched image and every remembered failure. For tests; see forget_cached_images.
image_cache_budget: The ceiling currently in force.
image_cache_bytes: The decoded bytes the store is currently holding.
images_in_flight: How many images are in flight right now.
install_text_scale: Installs the reader’s font-size setting until the returned guard is dropped.
paint_elevation: Paints the shadows of a surface elevation high, with corners radius, behind rect: BoxShadow::for_elevation’s three, each as BoxDecoration paints one. Nothing at a height of nought or in a colour with no opacity (milestone 606).
set_debug_default_target_platform_override: Makes default_target_platform report platform, or, with None, what it would report on its own: for trying another platform’s behaviour during development, and for tests. It is process-wide, so a test that sets it resets it before it returns.
set_image_cache_budget: Sets the ceiling on decoded network images held in memory, in bytes.
set_image_fetcher: Names the thing that gets bytes over the network.
surface_tint_opacity: How strongly a Material 3 surface is tinted at a given elevation.
text_scale: The reader’s font-size setting in force on this thread, or 1.0 outside any with_text_scale.
tile: Tiles t past the gradient’s ends (dart:ui’s TileMode): None where nothing is drawn.
trim_image_caches: Gives back every decoded image nobody is showing: what the system asks for when it is short of memory.
with_text_scale: Runs f with the reader’s font-size setting in force, restoring whatever was there before — including while a panic unwinds, so one bad frame cannot leave a stale scale installed for every frame after it.

Type Aliases§

ImageFetcher: Hands the bytes at url to the callback, once, from wherever suits the platform.
ImageHandle: A shared image handle: cheap to clone (reference counted), and stored as-is inside a crate::Primitive::Image.

Crate frus_core

Crate frus_core Copy item path

Re-exports§

Modules§

Structs§

Enums§

Constants§

Functions§

Type Aliases§

Crate frus_core