Trait DeltaRenderer 

pub trait DeltaRenderer {
    // Required methods
    fn render_first_delta(
        accumulated: &str,
        prefix: &str,
        colors: Colors,
        terminal_mode: TerminalMode,
    ) -> String;
    fn render_subsequent_delta(
        accumulated: &str,
        prefix: &str,
        colors: Colors,
        terminal_mode: TerminalMode,
    ) -> String;

    // Provided method
    fn render_completion(terminal_mode: TerminalMode) -> String { ... }
}

Renderer for streaming delta content.

This trait defines the contract for rendering streaming deltas consistently across all parsers. Implementations must ensure:

1. First chunk: Shows prefix with accumulated content, ending with newline + cursor up
2. Subsequent chunks: Clear line, rewrite with prefix and accumulated content, newline + cursor up
3. Completion: Move cursor down + newline when streaming completes

Rendering Rules

• render_first_delta(): Called for the first delta of a content block

  • Must include prefix
  • Must end with newline + cursor up (\n\x1b[1A) for in-place updates (in Full mode)
  • Shows the accumulated content so far

• render_subsequent_delta(): Called for subsequent deltas

  • Must include prefix (rewrite entire line)
  • Must use \x1b[2K\r to clear entire line and return to start (in Full mode)
  • Shows the full accumulated content (not just the new delta)
  • Must end with newline + cursor up (\n\x1b[1A) (in Full mode)

• render_completion(): Called when streaming completes

  • Returns cursor down + newline (\x1b[1B\n) in Full mode
  • Returns simple newline in Basic/None mode

Terminal Mode Awareness

The renderer automatically adapts output based on terminal capability:

• Full mode: Uses cursor positioning for in-place updates
• Basic mode: Uses colors but simple line output (no cursor positioning)
• None mode: Plain text output (no ANSI sequences)

Example

use crate::json_parser::delta_display::DeltaRenderer;
use crate::logger::Colors;
use crate::json_parser::TerminalMode;

let colors = Colors { enabled: true };
let terminal_mode = TerminalMode::detect();

// First chunk
let output = DeltaRenderer::render_first_delta(
    "Hello",
    "ccs-glm",
    colors,
    terminal_mode
);

// Second chunk
let output = DeltaRenderer::render_subsequent_delta(
    "Hello World",
    "ccs-glm",
    colors,
    terminal_mode
);

// Complete
let output = DeltaRenderer::render_completion(terminal_mode);

Required Methods

fn render_first_delta( accumulated: &str, prefix: &str, colors: Colors, terminal_mode: TerminalMode, ) -> String

Render the first delta of a content block.

This is called when streaming begins for a new content block. The output should include the prefix and the accumulated content.

Arguments

• accumulated - The full accumulated content so far
• prefix - The agent prefix (e.g., “ccs-glm”)
• colors - Terminal colors
• terminal_mode - The detected terminal capability mode

Returns

A formatted string with prefix and content. In Full mode, ends with \n\x1b[1A.

fn render_subsequent_delta( accumulated: &str, prefix: &str, colors: Colors, terminal_mode: TerminalMode, ) -> String

Render a subsequent delta (in-place update).

This is called for all deltas after the first. The output should clear the entire line and rewrite with the prefix and accumulated content in Full mode, or append content in Basic/None mode.

Arguments

• accumulated - The full accumulated content so far
• prefix - The agent prefix (e.g., “ccs-glm”)
• colors - Terminal colors
• terminal_mode - The detected terminal capability mode

Returns

A formatted string with prefix and content.

Provided Methods

fn render_completion(terminal_mode: TerminalMode) -> String

Render the completion of streaming.

This is called when streaming completes to move cursor down and add newline. This method ONLY handles cursor state cleanup - it does NOT render content.

The streamed content is already visible on the terminal from previous deltas. This method simply positions the cursor correctly for subsequent output.

Arguments

• terminal_mode - The detected terminal capability mode

Returns

A string with appropriate cursor sequence for the terminal mode.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl DeltaRenderer for TextDeltaRenderer