Text Selection & Copy

AZUREAL supports mouse-driven text selection with clipboard integration. Drag to select text in the Viewer, Session, Input, or Edit Mode, then copy with a platform-appropriate shortcut.

Selecting Text

Click and drag within a pane to create a selection. The selection model works as follows:

1. Mouse down records the anchor point, converting screen coordinates to cache coordinates immediately. The anchor is tagged with a pane identifier (Viewer, Session, Input, or Edit Mode) so that drag events route to the correct handler.

2. Mouse drag extends the selection from the anchor to the current cursor position. Only the cursor position is re-mapped from screen to cache coordinates on each drag event – the anchor remains fixed in cache space, so auto-scrolling during drag does not shift the selection start.

3. Mouse up finalizes the selection.

Selections are stored as a four-tuple:

(start_line, start_col, end_line, end_col)

Values are normalized so that start is always before or equal to end, regardless of drag direction.

Auto-Scroll

When dragging above or below a pane’s visible content area, the pane automatically scrolls in that direction. Because the anchor is stored in cache coordinates (not screen coordinates), the starting point of the selection remains stable as the viewport moves.

Pane-Specific Behavior

Viewer

• Selection highlighting is applied per-line via apply_selection_to_line().
• Line number gutter is excluded from selection. When copying, the gutter (line numbers) is stripped so only file content reaches the clipboard.
• In markdown preview mode (no line numbers), selection covers the full rendered width.

Session

• Selection respects content bounds – bubble chrome is excluded. Gutters, borders, headers, and decorative elements (the orange | gutter, AZURE | border, colored-background headers, bottom borders, code fences) are not selectable.
• Each cache line’s selectable region is computed by compute_line_content_bounds(). Lines that are entirely decorative (bounds (0, 0)) are skipped during selection highlighting.
• Copy extracts only the textual content within those bounds, trims leading and trailing blank lines, and skips decoration lines.

Input

• Selection maps screen coordinates to character indices using screen_to_input_char(), accounting for word-wrap break points.
• The fast-draw path for the input pane is bypassed when a selection is active, ensuring selection styling renders correctly.

Edit Mode

• When the Viewer is in edit mode, clicks and drags use screen_to_edit_pos() to map screen coordinates to source-line and source-column positions, walking source lines and summing wrap counts.
• Edit mode selections are stored separately as viewer_edit_selection: Option<(anchor_line, anchor_col, drag_line, drag_col)> and move the edit cursor to the drag endpoint.

Copying

Cmd+C (macOS) or Ctrl+C (Windows / Linux) copies selected text from whichever pane has an active selection.

Clipboard access uses the arboard crate for cross-platform system clipboard integration.

Git Mode

In Git Mode, Cmd+C and Cmd+A are intercepted before the git panel’s own input handler. If no viewer selection exists, Cmd+C falls back to copying the result_message from the git status box. Cmd+A selects the status box when the viewer cache is empty.

Clearing Selections

Selections are cleared automatically when any of the following occurs:

• Click anywhere (a new click starts fresh).
• Scroll in any pane.
• Tab or Shift+Tab (focus change).
• Focus change via mouse click on a different pane.

This ensures stale selections do not linger after navigation.

Selection Rendering

Selected text is highlighted with an Rgb(60, 60, 100) background color. The highlighting is applied by splitting styled spans at the selection boundaries and patching the background color of the overlapping region. This runs at O(spans-in-line) per visible line – negligible rendering cost.