Script Kit UI Components

Component architecture for GPUI-based UI in Script Kit.

Core Pattern: Colors Struct

Every component uses a pre-computed Colors struct for efficient closure use:

#[derive(Clone, Copy)]
pub struct ListItemColors {
    pub text_primary: u32,
    pub text_secondary: u32,
    pub background: u32,
    pub selected_opacity: f32,
    // ... other colors
}

impl ListItemColors {
    pub fn from_theme(theme: &Theme) -> Self { /* ... */ }
    pub fn from_design(colors: &DesignColors) -> Self { /* ... */ }
}

Why: Closures in GPUI can't clone full Theme. Extract primitive values (u32, f32) into Copy struct.

ListItem Component

Reusable list item for virtualized lists. Fixed height (48px) for uniform_list.

Basic Usage

use crate::list_item::{ListItem, ListItemColors, LIST_ITEM_HEIGHT};

let colors = ListItemColors::from_theme(&theme);

ListItem::new("Item Name", colors)
    .description("Optional description")
    .icon("📋")  // Emoji
    .shortcut("⌘O")
    .selected(is_selected)
    .hovered(is_hovered)
    .with_accent_bar(true)

Icon Types

pub enum IconKind {
    Emoji(String),           // "📋", "⚡"
    Image(Arc<RenderImage>), // Pre-decoded PNG (decode ONCE, not per-render)
    Svg(String),             // Icon name: "File", "Terminal", "Code"
}

// Use builder methods:
.icon("📋")                    // Emoji shorthand
.icon_image(decoded_image)     // Pre-decoded RenderImage
.icon_kind(IconKind::Svg("File".into()))

Critical: Decode PNGs once at load time, not during render:

let render_image = decode_png_to_render_image(&png_bytes)?;
ListItem::new(name, colors).icon_image(render_image)

Grouped Lists with Section Headers

For lists with sections (e.g., "Recent", "Main"):

use crate::list_item::{GroupedListItem, GroupedListState, render_section_header};

// Build items with headers
let items: Vec<GroupedListItem> = vec![
    GroupedListItem::SectionHeader("RECENT".into()),
    GroupedListItem::Item(0),
    GroupedListItem::Item(1),
    GroupedListItem::SectionHeader("MAIN".into()),
    GroupedListItem::Item(2),
];

// Create state for efficient navigation
let state = GroupedListState::from_items(&items);

// Navigate skipping headers
let next = state.next_selectable(current_idx);
let prev = state.prev_selectable(current_idx);

// Coerce selection to valid item (never lands on header)
let valid_idx = coerce_selection(&items, proposed_idx);

UnifiedListItem Component

Enhanced list item with fuzzy match highlighting and flexible content slots.

Basic Usage

use crate::components::unified_list_item::{
    UnifiedListItem, UnifiedListItemColors, TextContent,
    LeadingContent, TrailingContent, ItemState, Density
};

let colors = UnifiedListItemColors::from_theme(&theme);

UnifiedListItem::new("item-0", TextContent::plain("Title"))
    .subtitle(TextContent::plain("Subtitle"))
    .leading(LeadingContent::Emoji("📋".into()))
    .trailing(TrailingContent::Shortcut("⌘O".into()))
    .state(ItemState { is_selected: true, ..Default::default() })
    .colors(colors)

Fuzzy Match Highlighting

// Highlight matched characters in title
let title = TextContent::highlighted(
    "my-script.ts",
    vec![0..2, 3..5]  // Byte ranges to highlight
);

UnifiedListItem::new("item-0", title)

Content Types

// Leading (left side)
LeadingContent::Emoji("📋".into())
LeadingContent::Icon { name: "File".into(), color: None }
LeadingContent::AppIcon(arc_render_image)
LeadingContent::AppIconPlaceholder

// Trailing (right side)
TrailingContent::Shortcut("⌘O".into())
TrailingContent::Hint("Enter".into())
TrailingContent::Count(42)
TrailingContent::Chevron
TrailingContent::Checkmark

Density

// 48px height (default)
.density(Density::Comfortable)

// 40px height
.density(Density::Compact)

Button Component

use crate::components::{Button, ButtonColors, ButtonVariant};

let colors = ButtonColors::from_theme(&theme);

Button::new("Run", colors)
    .variant(ButtonVariant::Primary)  // Primary, Ghost, Icon
    .shortcut("⌘R")
    .on_click(Box::new(|event, window, cx| {
        // Handle click
    }))

PromptContainer Component

Container for prompt windows with header/content/footer layout:

use crate::components::{PromptContainer, PromptContainerColors, PromptContainerConfig};

let colors = PromptContainerColors::from_theme(&theme);
let config = PromptContainerConfig::new()
    .rounded_corners(12.0)
    .show_divider(true)
    .background_opacity(0xE8);

PromptContainer::new(colors)
    .config(config)
    .header(header_element)
    .content(content_element)
    .footer(footer_element)
    // Or use hint shorthand:
    .hint("Press Enter to select")

Panel Configuration

Window-level settings for macOS floating panels:

use crate::panel::{WindowVibrancy, PlaceholderConfig, CursorStyle};

// Vibrancy (blur effect)
WindowVibrancy::Blurred   // macOS vibrancy (default, recommended)
WindowVibrancy::Opaque    // Solid background
WindowVibrancy::Transparent

// Header layout constants
use crate::panel::{HEADER_PADDING_X, HEADER_PADDING_Y, HEADER_TOTAL_HEIGHT};

// Cursor styling for inputs
let cursor = CursorStyle::large();  // For .text_lg()
let cursor = CursorStyle::medium(); // For .text_md()
let cursor = CursorStyle::small();  // For .text_sm()

Component Design Rules

1. Colors struct: Always Copy/Clone, use from_theme() and from_design()
2. Builder pattern: Fluent API with .method() chaining
3. IntoElement trait: Implement RenderOnce for GPUI compatibility
4. Fixed heights: Use constants for virtualized lists (LIST_ITEM_HEIGHT = 48px)
5. Pre-decode images: Never decode PNGs during render
6. Hover states: Use GPUI's .hover() for instant feedback, state for tracked hover

File Structure

src/
├── list_item.rs          # ListItem, IconKind, GroupedListItem
├── panel.rs              # Window config, placeholders, cursor
└── components/
    ├── mod.rs            # Re-exports
    ├── button.rs         # Button component
    ├── prompt_container.rs
    ├── prompt_header.rs
    ├── prompt_footer.rs
    ├── unified_list_item/
    │   ├── mod.rs
    │   ├── types.rs      # TextContent, LeadingContent, etc.
    │   └── render.rs     # UnifiedListItem, SectionHeader
    └── ...