53 lines
2.9 KiB
Markdown
53 lines
2.9 KiB
Markdown
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# EPUB Table Rendering Implementation
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## Task
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Replace the `[Table omitted]` placeholder in the EPUB reader with full column-aligned table rendering, including grid lines, proportional column widths, and proper serialization.
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## Changes Made
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### New file
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- **`lib/Epub/Epub/TableData.h`** -- Lightweight structs (`TableCell`, `TableRow`, `TableData`) for buffering table content during SAX parsing.
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### Modified files
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- **`lib/Epub/Epub/ParsedText.h` / `.cpp`**
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- Added `getNaturalWidth()` public method to measure the single-line content width of a ParsedText. Used by column width calculation.
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- **`lib/Epub/Epub/Page.h` / `.cpp`**
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- Added `TAG_PageTableRow = 2` to `PageElementTag` enum.
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- Added `getTag()` pure virtual method to `PageElement` base class for tag-based serialization.
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- Added `PageTableCellData` struct (cell lines, column width, x-offset).
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- Added `PageTableRow` class with render (grid lines + cell text), serialize, and deserialize support.
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- Updated `Page::serialize()` to use `el->getTag()` instead of hardcoded tag.
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- Updated `Page::deserialize()` to handle `TAG_PageTableRow`.
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- **`lib/Epub/Epub/parsers/ChapterHtmlSlimParser.h`**
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- Added `#include "../TableData.h"`.
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- Added table state fields: `bool inTable`, `std::unique_ptr<TableData> tableData`.
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- Added `processTable()` and `addTableRowToPage()` method declarations.
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- **`lib/Epub/Epub/parsers/ChapterHtmlSlimParser.cpp`**
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- Added table-related tag arrays (`TABLE_TRANSPARENT_TAGS`, `TABLE_SKIP_TAGS`).
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- Replaced `[Table omitted]` placeholder with full table buffering logic in `startElement`.
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- Modified `startNewTextBlock` to be a no-op when inside a table (cell content stays in one ParsedText).
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- Added table close handling in `endElement` for `</td>`, `</th>`, and `</table>`.
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- Disabled the 750-word early split when inside a table.
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- Implemented `processTable()`: column width calculation (natural + proportional distribution), per-cell layout via `layoutAndExtractLines`, `PageTableRow` creation.
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- Implemented `addTableRowToPage()`: page-break handling for table rows.
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## Design Decisions
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- Tables are buffered entirely during parsing, then processed on `</table>` close (two-pass: measure then layout).
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- Column widths are proportional to natural content width, with equal distribution of extra space when content fits.
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- Grid lines (1px) drawn around every cell; 2px horizontal cell padding.
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- Nested tables are skipped (v1 limitation).
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- `<caption>`, `<colgroup>`, `<col>` are skipped; `<thead>`, `<tbody>`, `<tfoot>` are transparent.
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- `<th>` cells get bold text. Cell text is left-aligned with no paragraph indent.
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- Serialization is backward-compatible: old firmware encountering the new tag will re-parse the section.
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## Follow-up Items
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- Nested table support (currently skipped)
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- `colspan` / `rowspan` support
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- `<caption>` rendering as centered text above the table
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- CSS border detection (currently always draws grid lines)
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- Consider CSS-based cell alignment
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