* fix(chat): the AI reads and draws the page the user is viewing
The model always got the first page and display_diagram replaced the whole
file with one page, so drawing on page 3 of a multi-page file deleted the
other pages (#241), and edits went to page 1 while the user looked at
another page.
Now a turn records the page the user is viewing when the message is sent.
That page's model goes to the model (also as previousXml, on regenerate and
in edit_diagram error messages), selected shapes are sent on any page,
display_diagram and append_diagram replace only that page (a drawing that
brings several pages still replaces the file), edit_diagram targets it,
and the streaming preview draws on it. Compact cells and default styles
take the layer and the edges of that page, in the preview and in
editDiagram. The editor bridge replaces the current page in place when the
other pages are unchanged, so Ctrl+Z undoes an AI change on a multi-page
file in one step; when a full load is needed, the user's page is shown
again afterwards. Version summaries and the compare dialog count the page
the change was made on.
* test: read the failed edit's output without unsafe optional chaining
The model defines reused styles once as <mxStyle name="..." value="..."/> and
refers to them by name, and writes shapes as one self-closing mxCell with
x, y, w, h and edges with source and target. style-classes.ts and
compact-cells.ts expand both back into standard draw.io XML after validation
and add draw.io's html=1 / whiteSpace=wrap defaults; the diagram shown to the
model is folded into the same notation. Prompts, tool descriptions and the MCP
drawing guide teach the notation with shared examples.
Measured on the five start-screen examples against main: gpt-6-luna 35% fewer
output tokens, Claude Opus 5.5 41% fewer. Two five-model review rounds fixed
quote-aware cell matching, attribute escaping, edge/vertex inference, root-id
and layer handling, and several auto-fix gaps.
The canvas now fills the window and the chat floats on its right. draw.io is
served from our own origin (public/drawio, downloaded at build time and
checked against the release's SHA-256), so the app can drive the editor
directly:
- every AI change becomes a version card with a thumbnail; compare, restore
or undo it, and Ctrl+Z on the canvas takes an AI change back in one step
- shapes the AI just changed are highlighted on the canvas
- selected shapes appear as a chip and are sent to the model
- draw.io's own simple UI: its toolbar, menus (auto layout, Mermaid, CSV
import) and page tabs; the shape library starts closed
- new start screen, session rename and switcher, open .drawio files
- settings split into Models & keys, Appearance, Advanced and About
- Bedrock in the model settings also takes an API key instead of access keys
- phones switch between canvas and chat
- dark mode uses draw.io's own dark mode, with neutral greys around it
With an external draw.io (NEXT_PUBLIC_DRAWIO_BASE_URL) the features above
that need same origin are off.
The chat logic moved from the 1500-line chat panel into a chat engine plus
small UI components; zustand holds canvas, versions, settings and UI state.
Dayuan Jiang