41d9ca6e01
Adds curved arrows between consecutive blocks in reading order with numeric labels. Arrows use quadratic bezier curves with control points at midpoint + 10pt downward. Limits to 50 arrows to prevent visual clutter. - Add render_reading_order function returning SVG path and text elements - Include data-* attributes for tooltip consumption - Add comprehensive unit tests (10/10 passing) - Export reading_order module from inspect/render/mod.rs Acceptance criteria: - Helper compiles and produces valid SVG output ✅ - Layer is independently toggleable via CSS class ✅ - data-* attrs populated ✅ - Unit tests pass ✅ Closes: pdftract-6559n
93 lines
3.2 KiB
Markdown
93 lines
3.2 KiB
Markdown
# pdftract-6559n: render_reading_order Implementation
|
|
|
|
## Bead
|
|
**ID:** pdftract-6559n
|
|
**Title:** Inspector layer renderer: render_reading_order (curved numbered arrows)
|
|
|
|
## Implementation Summary
|
|
|
|
Implemented the `render_reading_order` function that renders curved arrows between consecutive blocks in reading order for the inspector debug viewer.
|
|
|
|
### Files Created
|
|
- `crates/pdftract-cli/src/inspect/render/reading_order.rs` (377 lines)
|
|
|
|
### Files Modified
|
|
- `crates/pdftract-cli/src/inspect/render/mod.rs` - Added `reading_order` module export
|
|
|
|
## Acceptance Criteria Status
|
|
|
|
### PASS
|
|
- ✅ Helper compiles and produces valid SVG output
|
|
- Function signature: `pub fn render_reading_order(blocks: &[BlockJson], order: &[usize]) -> Vec<String>`
|
|
- Returns `<path>` elements for curved arrows and `<text>` elements for numeric labels
|
|
- ✅ Layer is independently toggleable via CSS class
|
|
- Arrows have `class="reading-order-arrow"`
|
|
- Labels have `class="reading-order-label"`
|
|
- ✅ data-* attrs populated for downstream UI consumption
|
|
- `data-from-block`: index of source block
|
|
- `data-to-block`: index of target block
|
|
- `data-reading-index`: sequence number (1, 2, 3, ...)
|
|
- ✅ Unit tests pass (10/10)
|
|
- Empty input handling
|
|
- Single block (no arrows)
|
|
- Two blocks (one arrow)
|
|
- Three blocks (two arrows)
|
|
- Non-sequential reading order (columnar layouts)
|
|
- Max arrows limit (50 arrows to prevent clutter)
|
|
- Block center calculation
|
|
- CSS class presence
|
|
- Out-of-bounds index handling
|
|
|
|
### Technical Details
|
|
|
|
**Arrow rendering:**
|
|
- Stroke: blue (#3b82f6) with 1.5px width
|
|
- Marker-end: url(#arrowhead) - expects arrowhead definition in parent SVG `<defs>`
|
|
- Quadratic bezier curves (`Q` command) with control point at midpoint + 10pt downward
|
|
- SVG path format: `M{x1},{y1} Q{cx},{cy} {x2},{y2}`
|
|
|
|
**Labels:**
|
|
- Numeric labels (1, 2, 3, ...) at arrow midpoints
|
|
- Positioned 5pt above the midpoint
|
|
- Blue (#3b82f6), bold, 10pt font
|
|
|
|
**Performance:**
|
|
- Limits to first 50 blocks (49 arrows max) to prevent visual clutter
|
|
- O(n) complexity where n = number of arrows
|
|
|
|
## Testing
|
|
|
|
```bash
|
|
cargo test -p pdftract-cli --lib reading_order
|
|
```
|
|
|
|
All 10 tests pass:
|
|
- test_block_center
|
|
- test_block_center_fractional
|
|
- test_render_reading_order_empty
|
|
- test_render_reading_order_css_class
|
|
- test_render_reading_order_out_of_bounds_indices
|
|
- test_render_reading_order_non_sequential
|
|
- test_render_reading_order_single_block
|
|
- test_render_reading_order_three_blocks
|
|
- test_render_reading_order_two_blocks
|
|
- test_render_reading_order_max_arrows_limit
|
|
|
|
## Integration Notes
|
|
|
|
This renderer will be called by the inspector layer rendering pipeline (Phase 7.9.4) to generate the reading-order overlay layer. The SVG elements returned by this function are placed inside a `<g class="layer-reading-order">` group in the final output.
|
|
|
|
The parent SVG must define the arrowhead marker in `<defs>`:
|
|
```svg
|
|
<defs>
|
|
<marker id="arrowhead" markerWidth="10" markerHeight="10" refX="9" refY="3" orient="auto">
|
|
<path d="M0,0 L0,6 L9,3 z" fill="#3b82f6" />
|
|
</marker>
|
|
</defs>
|
|
```
|
|
|
|
## References
|
|
- Plan section: Phase 7.9 lines 2836-2845 (layer table)
|
|
- Coordinator: pdftract-liq5f (parent — 8 layer renderers bundle)
|
|
- Phase 7.9.3 (frontend CSS-toggling)
|
|
- Phase 7.9.6 (tooltip/search/tree consume data-* attrs)
|