Struct ViewContext 

pub struct ViewContext {
    pub size: Size,
    pub theme: Arc<Theme>,
    /* private fields */
}

The size this render call may draw into, plus the Theme in effect.

A ViewContext describes an allocated size, not the terminal size. When a parent component renders a child, it is responsible for narrowing the context to the child’s slot before calling Component::render. Children should treat size as authoritative — only the root component should assume the full terminal width.

Size contract

• Parents allocate sizes and pass size-scoped contexts to children.
• Children render into the size they were given. They do not negotiate width upward.
• Composition (stacking, side-by-side layout, padding) happens on Frame, not by reaching back into the parent’s ViewContext.

Construction

use tui::ViewContext;

// Default theme
let ctx = ViewContext::new((80, 24));

// Custom theme
use tui::Theme;
let ctx = ViewContext::new_with_theme((120, 40), Theme::default());

Size helpers

When rendering a child into part of the parent’s size, derive a new context with one of:

• with_size((w, h)) — Replace the entire size.
• with_width(w) — Replace just the width, keep the height.
• with_height(h) — Replace just the height, keep the width.
• inset(insets) — Shrink the size by Insets on each edge. Saturates at zero on each axis.

All helpers preserve the theme and (when the syntax feature is enabled) the syntax highlighter.

use tui::{Insets, ViewContext};

let parent = ViewContext::new((80, 24));

// Render a child in a left half of width 40.
let left = parent.with_width(40);

// Render a child inside a 2-column horizontal padding.
let padded = parent.inset(Insets::horizontal(2));

Size

Size holds the dimensions of an allocated render area as width (columns) and height (rows), both u16. Implements From<(u16, u16)> for convenient construction.

Other methods

• highlighter() — Access the SyntaxHighlighter (requires feature syntax).

See also

• Frame — The render artifact returned by Component::render. Composition primitives like fit, indent, vstack, and hstack operate on frames, not on the parent context.
• Insets — Edge insets used by inset().
• Theme — The semantic color palette.
• Renderer — Creates ViewContext automatically from its own state.

Fields

size: Size

The size this context allows the component to draw into. This is not the terminal size — parents pass child contexts whose size is the slice of the terminal allocated to the child.

theme: Arc<Theme>

Implementations

impl ViewContext

pub fn new(size: impl Into<Size>) -> Self

pub fn new_with_theme(size: impl Into<Size>, theme: Theme) -> Self

pub fn highlighter(&self) -> &SyntaxHighlighter

pub fn with_size(&self, size: impl Into<Size>) -> Self

Clone this context with a new size, preserving theme state.

pub fn with_width(&self, width: u16) -> Self

Clone this context with the width replaced, preserving height and theme.

pub fn with_height(&self, height: u16) -> Self

Clone this context with the height replaced, preserving width and theme.

pub fn inset(&self, insets: Insets) -> Self

Clone this context with the size shrunk by insets on each side. Saturates at zero on each axis.

Trait Implementations

impl Clone for ViewContext

fn clone(&self) -> ViewContext

Returns a duplicate of the value.

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

Performs copy-assignment from source.