Crate tessera_ui 

Tessera UI Framework

Tessera is a declarative, immediate-mode UI framework for Rust that emphasizes performance, flexibility, and extensibility through a functional approach and pluggable shader system.

Architecture Overview

Tessera’s architecture is built around several core concepts:

• Declarative Components: UI components are defined as functions with the #[tessera] macro
• Immediate Mode: The UI is rebuilt every frame, ensuring consistency and simplicity
• Pluggable Shaders: Custom WGPU shaders are first-class citizens for advanced visual effects
• Parallel Processing: Core operations like measurement utilize parallel computation
• Explicit State Management: Components are stateless with explicit state passing

Getting Started by Developer Level

🟢 Beginner Users - Building Basic Applications

If you’re new to Tessera and want to build applications using existing components:

Start with these modules:

• renderer - Core renderer and application lifecycle management
• Dp, Px - Basic measurement units for layouts
• Color - Color system for styling components

Key concepts to understand:

• How to set up a Renderer and run your application
• Using tessera-ui-basic-components for common UI elements
• Basic layout with row, column, and surface components

🟡 Intermediate Users - Custom Layout and Interaction

For developers who want to create custom components and handle complex layouts:

Essential functions and types:

• MeasureInput::measure_child - Measure child component sizes with constraints
• MeasureInput::place_child - Position child components in the layout
• InputHandlerFn - Handle user interactions and state changes
• Constraint, DimensionValue - Layout constraint system
• ComputedData - Return computed size and layout information

Key concepts:

• Understanding the measurement and placement phase
• Creating custom layout algorithms
• Managing component state through explicit input handlers
• Working with the constraint-based layout system

use tessera_ui::{ComputedData, Constraint, PxPosition, tessera};

#[tessera]
fn custom_layout(child: impl FnOnce()) {
    child();

    measure(Box::new(|input| {
        // Custom measurement logic here
    }));

    input_handler(Box::new(|input| {
        // Handle user interactions here
    }));
}

🔴 Advanced Users - Custom Rendering Pipelines

For developers building custom visual effects and rendering pipelines:

Advanced rendering modules:

• renderer::drawer - Custom drawable pipelines and draw commands
• renderer::compute - GPU compute pipelines for advanced effects
• DrawCommand, ComputeCommand - Low-level rendering commands
• DrawablePipeline, ComputablePipeline - Pipeline trait implementations
• PipelineRegistry, ComputePipelineRegistry - Pipeline management

Key concepts:

• Creating custom WGPU shaders and pipelines
• Managing GPU resources and compute operations
• Understanding the rendering command system
• Implementing advanced visual effects like lighting, shadows, and particles

Core Modules

Essential Types and Functions

• Renderer - Main application renderer and lifecycle manager
• MeasureInput - Context for layout measurement and placement
• Constraint, DimensionValue - Layout constraint system
• Dp, Px - Measurement units (device-independent and pixel units)
• Color - Color representation and utilities

Component System

• ComponentTree - Component tree management
• ComponentNode - Individual component node representation
• ComputedData - Layout computation results
• InputHandlerFn - State management and event handling

Event Handling

• CursorEvent - Mouse and touch input events
• Focus - Focus management system
• PressKeyEventType - Keyboard input handling

Rendering System

• renderer::drawer - Drawing pipeline system
• renderer::compute - Compute pipeline system
• DrawCommand, ComputeCommand - Rendering commands

Examples

Check out the example crate in the workspace for comprehensive examples demonstrating:

• Basic component usage
• Custom layouts and interactions
• Advanced shader effects
• Cross-platform deployment (Windows, Linux, macOS, Android)

Performance Considerations

Tessera is designed for high performance through:

• Parallel measurement computation using Rayon
• Efficient GPU utilization through custom shaders
• Minimal allocations in hot paths
• Optimized component tree traversal

Re-exports

pub use crate::accessibility::AccessibilityActionHandler;

pub use crate::accessibility::AccessibilityId;

pub use crate::accessibility::AccessibilityNode;

pub use crate::clipboard::Clipboard;

pub use crate::color::Color;

pub use crate::dp::Dp;

pub use crate::focus_state::Focus;

pub use crate::px::Px;

pub use crate::px::PxPosition;

pub use crate::px::PxRect;

pub use crate::px::PxSize;

pub use crate::renderer::BarrierRequirement;

pub use crate::renderer::Command;

pub use crate::renderer::Renderer;

pub use crate::renderer::compute;

pub use crate::renderer::compute::ComputablePipeline;

pub use crate::renderer::compute::ComputeCommand;

pub use crate::renderer::compute::ComputePipelineRegistry;

pub use crate::renderer::compute::ComputeResource;

pub use crate::renderer::compute::ComputeResourceManager;

pub use crate::renderer::compute::ComputeResourceRef;

pub use crate::renderer::drawer;

pub use crate::renderer::drawer::DrawCommand;

pub use crate::renderer::drawer::DrawablePipeline;

pub use crate::renderer::drawer::PipelineRegistry;

pub use crate::renderer::drawer::command;

pub use crate::runtime::TesseraRuntime;

pub use accesskit;

pub use wgpu;

pub use winit;

pub use tessera_ui_shard;

Modules

accessibility

Accessibility Support

clipboard

Provides a cross-platform clipboard manager for text manipulation.

color

Color utilities for the Tessera UI framework.

dp

Density-Independent Pixels (Dp)

dyn_eq

This module provides a workaround for dynamic equality testing of trait objects of the DrawCommand trait.

dyn_eq_compute

This module provides a workaround for dynamic equality testing of trait objects of the ComputeCommand trait.

focus_state

Focus State Management

px

Physical pixel coordinate system for Tessera UI framework.

renderer

The core rendering system for the Tessera UI framework. This module provides the main Renderer struct that manages the application lifecycle, event handling, and rendering pipeline for cross-platform UI applications.

router

Root routing entry utilities.

runtime

Tessera Runtime System

Structs

Arena

An Arena structure containing certain Nodes.

ComponentNode

A ComponentNode is a node in the component tree. It represents all information about a component.

ComponentNodeMetaData

Contains metadata of the component node.

ComponentTree

Respents a component tree

ComputedData

Layout information computed at the measure stage, representing the size of a node.

Constraint

Represents layout constraints for a component node.

CursorEvent

Represents a single cursor or touch event with timing information.

ImeRequest

A request to the windowing system to open an Input Method Editor (IME). This is typically used for text input components.

InputHandlerInput

Input for the input handler function (InputHandlerFn).

MeasureInput

Input for the measure function (MeasureFn).

NodeId

A node identifier within a particular Arena.

ScrollEventConent

Contains scroll movement data for scroll events.

Enums

CursorEventContent

Enumeration of all possible cursor event types.

DimensionValue

Defines how a dimension (width or height) should be calculated.

GestureState

Describes the high-level gesture classification of a cursor event.

MeasurementError

Represents errors that can occur during node measurement.

PressKeyEventType

Represents the different types of cursor buttons or touch interactions.

Type Aliases

ComponentNodeMetaDatas

Contains all component nodes’ metadatas, using a thread-safe DashMap.

ComponentNodeTree

A tree of component nodes, using indextree::Arena for storage.

InputHandlerFn

A InputHandlerFn is a function that handles state changes for a component.

MeasureFn

A MeasureFn is a function that takes an input Constraint and its children nodes, finishes placementing inside, and returns its size (ComputedData) or an error.

Attribute Macros

shard

Transforms a function into a shard component that can be navigated to via the routing system and (optionally) provided with a lazily‑initialized per‑shard state.

tessera

Transforms a regular Rust function into a Tessera UI component.