Layout and Rendering

Ansiq rendering is not one step. The current pipeline is:

render retained tree
-> rerender dirty subtrees
-> partial relayout
-> invalidated regions
-> redraw framebuffer
-> diff
-> terminal patch emission

Continue the NotesApp

Assume NotesApp now has:

• a List on the left
• an input area on the right
• a footer

In other words, the same version of the app that now has multiple interactive regions.

When you type one extra character, the desired behavior is not:

• rebuild the whole app
• recompute the whole layout
• redraw the whole terminal surface

It should be much closer to:

input signal changed
-> dirty component scope
-> rerender only the composer subtree
-> relayout only affected ancestors if geometry changed
-> redraw only invalidated regions
-> emit the minimal terminal patch

Partial relayout

After subtree replacement, the nodes that may need layout work are usually:

• the replaced subtree
• its ancestor chain
• siblings affected by geometry shifts

That is very different from treating all layout work as global.

This is also why the previous pages kept separating local signals from app-level state.
Cleaner state boundaries make cleaner dirty-scope and relayout boundaries possible.

Damage model

Layout changes and redraw changes are related but not identical.

Ansiq also needs to answer:

• which regions are actually invalidated
• which regions need redraw
• which regions can remain untouched

Framebuffer diff

Even after redraw, the runtime still computes framebuffer diffs before terminal patch emission.

So the goal is local work all the way down:

• local rerender
• local relayout
• local redraw
• minimal patch emission

If you read this page together with the streaming page, Ansiq’s position becomes clearer:

• async work brings messages back
• the app turns messages into state
• the runtime turns state changes into the smallest practical terminal update

Next

Continue with Viewport and History.
The same app will now be pushed toward transcript and shell-like behavior so the surface layer becomes easier to understand.