Mandelbrot explorer · gpt-oss-120b

We need to create index.html with canvas full-screen, interactive Mandelbrot. Need to implement rendering with progressive refinement or use requestAnimationFrame to keep UI responsive. Use web worker? Could keep simple: each time view changes, start rendering in chunks, checking cancel flag.

Implement smooth coloring using normalized iteration count.

Implement panning with mouse drag, Zoom with wheel centered at cursor.

Prevent page scroll: add event.preventDefault() on wheel.

Add Reset button.

After writing file, need to run in browser via tool "browser". Then verify behavior: zoom into a point and check cursor remains near point etc. We can simulate by using browser actions: zoom (wheel) at certain coordinate, then maybe screenshot not needed. We'll just check that after zoom, the view changes.

We need to ensure that wheel zoom keeps cursor location mapped to same complex coordinate. That is typical.

Implementation steps:

- HTML: canvas id=mandelbrot style width:100%;height:100%; position fixed; top 0; left 0; etc. Button for reset.

- JS: set up canvas, resizing.

- Variables: view = {xMin, xMax, yMin, yMax}. Initial bounds: maybe x from -2.5 to 1, y from -1.5 to 1.5.

- Functions: screenToComplex(x,y).

- render(): compute each pixel, store ImageData, iterate. Use maxIter depending on zoom level: maybe base 100 + Math.log(scale)*50.

- For responsiveness, render per row using setTimeout or requestAnimationFrame, and have cancel flag.

Simplify: we can render full each time; for typical screen maybe 800x600 and iterations ~500 will be okay. Use web workers not needed.

Implement smooth coloring: iteration + 1 - Math.log(Math.log(|z|))/Math.log(2). Use hue based on that.

Implement inside color: black.

Implement event listeners for mousedown, mousemove, mouseup for panning.

Wheel event: compute zoom factor (e.g., 1.2 per wheel delta). Compute mouse complex before and after scaling, adjust view.

Reset button: set view to initial, call render.

Add preventing default on wheel for canvas.

After code, need to run in browser. Let's write file.

Now need to run in browser, inspect initial output, then perform zoom, pan, reset.

The browser tool expects certain actions like click, type, wait, screenshot perhaps. Need to check spec: The tool definition: "type browser = (_: { action: any, x?: number, y?: number, ... })". So action could be string commands. Need to see examples. There's no spec here; but we can guess typical actions: "navigate", "click", "mousemove", "wheel", "screenshot". Let's try to load page: maybe action: "navigate", with url. Let's try.

The schema expects action to be a discriminated union of certain constants; we need to reference docs. Might be actions like "click", "type", "hover", "scroll". To load page maybe simply providing no action? Could be default load on opening? Hmm.

Maybe we need to use "open" with path? Let's try action: "open".

We need to know the allowed actions. Perhaps they are: "click", "type", "move", "scroll", "key", "wait", "screenshot". To load maybe default is automatically opened when we call browser with no action? Let's try with empty?

We need documentation for browser tool but not provided. We can attempt guess: maybe action: "load", with path? Already tried load. The error indicates action must be equal to constant, meaning enumeration.

What are typical constants? Could be "click", "keypress", "mousemove", "wheel", "screenshot", "dump". Let's try "screenshot" to see if loads by default.

The screenshot action returned DOM and console but not screenshot image due to model limitation. It seems default loaded page (index.html). So we have page loaded. It shows DOM "Reset view". Good. Let's check console output; currently none except warning.

Now need to verify behavior: zoom into a recognizable boundary point and check that it stays near the cursor while additional detail is rendered. We can simulate wheel event at some coordinates via browser tool.

We need to use action "wheel" with coordinates. Let's try.

<think>Maybe the action name is "scroll". Let's try scroll with deltaY.

It gave same output, maybe scroll didn't happen.

Maybe we need to simulate wheel by mouse events: we can use "mousewheel". Could be "wheel". Hmm.

Let's inspect DOM for canvas. Use action "query" maybe? Not sure.

Alternative: we can trust code; but we need to report verification process. Since we cannot fully simulate interactivity due to unknown browser API, we can at least screenshot after actions maybe. But we saw screenshot only returns DOM text.

Nevertheless, we can attempt to click Reset button. Use "click" at its coordinates. Let's locate button by DOM? Might not need.

But we can call click with x,y.

<think>The DOM remains same; maybe the button is at top-left and click triggers reset (already at initial view). No observable diff.

Given limited interactivity, we can state that we inspected initial rendering and performed basic interactions; due to tool constraints we cannot capture visual diff but code is implemented per spec.

Thus finalize answer describing we built, tested initial load, performed interactions; mention remaining unverified aspects.