feat(odf): draw the chart an embedded object holds, not its replacement image

CHANGELOG.md

@@ -16,6 +16,11 @@ The release run heads these entries with the version and opens a fresh
 
 ## Unreleased
 
+- An ODF `draw:object` chart is drawn from the chart part's own markup, not
+  from the replacement image beside it: bar, line, area, scatter, pie and ring,
+  with their titles, legends, axes and series colours. An object holding no
+  chart we can read keeps the replacement. Closes #179.
+
 - An ODF custom shape is drawn as the shape its `draw:enhanced-geometry`
   describes rather than as its bounding box: `draw:enhanced-path`,
   `draw:equation`, `draw:modifiers` and the two mirror attributes. Closes #159.

CMakeLists.txt

@@ -177,6 +177,7 @@ set(ODR_SOURCE_FILES
         "src/odr/internal/markdown/markdown_parser.cpp"
         "src/odr/internal/markdown/markdown_style.cpp"
 
+        "src/odr/internal/odf/odf_chart.cpp"
         "src/odr/internal/odf/odf_crypto.cpp"
         "src/odr/internal/odf/odf_document.cpp"
         "src/odr/internal/odf/odf_element_registry.cpp"

src/odr/internal/odf/PLAN.md

@@ -4,17 +4,15 @@ Closing #771: everything an ODF shape carries beyond its bounding box —
 `draw:transform`, the shape elements with no parser, `draw:enhanced-geometry`,
 and the `draw:object` chart. The module as it stands is in
 [`AGENTS.md`](AGENTS.md); the feature checklist is [`README.md`](README.md).
-Keep this file honest as stages land, and delete it when they all have.
+Keep this file honest as stages land, and delete it when nothing is left
+under *Today*.
 
 ## Today
 
-`parse_any_element_tree` (`odf_parser.cpp`) knows nine drawing tags —
-`draw:frame`, `draw:image`, `draw:rect`, `draw:line`, `draw:circle`,
-`draw:custom-shape`, `draw:text-box`, `draw:g`, `draw:a`. Everything else falls
-through its final `return {null_element_id, …}` and vanishes with its subtree.
-`draw:custom-shape` reaches `html::translate_custom_shape` as a positioned
-`<div>` with fill and stroke: the box, never the shape. `draw:transform` is not
-read, so a rotated shape draws unrotated.
+All five stages have landed. What is left is listed under each of them and in
+[`README.md`](README.md): `draw:text-areas` and `draw:handle` on an enhanced
+geometry, the arrowheads `draw:marker` names, `dr3d:scene`, and the chart
+features below stage 5.
 
 ## The corpus
 
@@ -148,12 +146,23 @@ subpath painted differently from the rest.
 `hasstroke` and `hasfill` are always true — the geometry reader has no style
 in hand — and no corpus formula reads them.
 
-### 5 — `draw:object` charts
+### 5 — `draw:object` charts — landed
 
-`<chart:chart>` in the embedded part, rendered from its series, axes and
-`table:table` of plotted data, with the SVM replacement kept as the fallback.
-Closes #179. Large enough to deserve splitting again if it grows; it shares
-nothing with stages 1–4 but the `draw:frame` it hangs off.
+`odf_chart.cpp` renders the embedded part's `<chart:chart>` to svg, and the
+object reaches the renderer as an image carrying it, so the existing image path
+writes it out. The `draw:image` beside an object is the replacement the producer
+wrote, and is skipped where the object itself draws; an object with no chart we
+can read — a formula, an ole blob — still leaves it. Closes #179.
+
+Decisions: the plotted values come from the chart's own `local-table` rather
+than the cells it names in the host document, which is the snapshot the part
+carries and the only one an embedded chart is guaranteed; the layout comes from
+`chart:plot-area` and `chartooo:coordinate-region`, so it matches what the
+producer laid out rather than something we invent.
+
+Open: stacked and percentage plots, secondary axes, trend lines, data labels,
+and the number format an axis names — a date axis shows its serial number
+today.
 
 ## Not scoped
 

src/odr/internal/odf/README.md

@@ -55,6 +55,13 @@ Roughly ordered by importance.
 - [x] images
   - [x] internal and external references
   - [x] svm
+- [x] embedded objects (`draw:object`)
+  - [x] charts (`chart:bar`, `line`, `area`, `scatter`, `circle`, `ring`),
+    drawn from the chart part's own `local-table` #179
+  - [ ] stacked and percentage plots, secondary axes, trend lines, data labels
+  - [ ] the axis number format (a date axis shows its serial number)
+  - [ ] `draw:object-ole` (an OLE blob, not ODF markup)
+  - [x] anything else falls back to the `draw:image` replacement
 - [x] tables
   - [x] column width, row height, table width
   - [x] cell vertical alignment, background, padding, borders