From 6bae1ad12bbbf7eb44c8dd05429f1338b1a8e323 Mon Sep 17 00:00:00 2001
From: Kit Langton <kit.langton@gmail.com>
Date: Tue, 20 Oct 2026 00:13:13 -0700
Subject: [PATCH] feat(app): text rendering controls in the debug bar (#57326)

---
 packages/gui-extensions/src/debug/bar.tsx     |  9 +++
 packages/gui-extensions/src/debug/i18n/en.ts  |  3 +
 .../gui-extensions/src/debug/renderer.tsx     | 13 ++++
 .../gui-extensions/src/debug/type-panel.tsx   | 59 +++++++++++++++
 packages/gui-extensions/src/debug/type.ts     | 75 +++++++++++++++++++
 5 files changed, 159 insertions(+)
 create mode 100644 packages/gui-extensions/src/debug/type-panel.tsx
 create mode 100644 packages/gui-extensions/src/debug/type.ts

diff --git a/packages/gui-extensions/src/debug/bar.tsx b/packages/gui-extensions/src/debug/bar.tsx
index 4893b159ab4..5dde517967e 100644
--- a/packages/gui-extensions/src/debug/bar.tsx
+++ b/packages/gui-extensions/src/debug/bar.tsx
@@ -196,6 +196,7 @@ export default function DebugBar(props: {
   diagnostics?: boolean
   inline?: boolean
   motion?: { open: boolean; toggle: () => void }
+  type?: { open: boolean; toggle: () => void }
 }) {
   const ctx = useExtension()
   const router = ctx.router
@@ -758,6 +759,14 @@ export default function DebugBar(props: {
               value={ctx.t(globals().slow ? "focus.on" : "focus.off")}
               onClick={() => motionTuning.set(motionGlobals.slow, !globals().slow)}
             />
+            <ToggleCell
+              active={!!props.type?.open}
+              inline={props.inline}
+              label={ctx.t("type.label")}
+              tip={ctx.t("type.tip")}
+              value={ctx.t(props.type?.open ? "focus.on" : "focus.off")}
+              onClick={() => props.type?.toggle()}
+            />
             <ToggleCell
               active={!!props.motion?.open}
               inline={props.inline}
diff --git a/packages/gui-extensions/src/debug/i18n/en.ts b/packages/gui-extensions/src/debug/i18n/en.ts
index 4580c954676..f0aa7e1d84d 100644
--- a/packages/gui-extensions/src/debug/i18n/en.ts
+++ b/packages/gui-extensions/src/debug/i18n/en.ts
@@ -35,6 +35,9 @@ export default {
   "motion.label": "MOTION",
   "motion.title": "Motion",
   "motion.tip": "Tune animation springs live. Changes persist on this device.",
+  "type.label": "TYPE",
+  "type.title": "Type",
+  "type.tip": "Tune text smoothing, family, weight and tracking live. Changes persist on this device.",
   "speed.label": "SPEED",
   "speed.tip": "Global animation speed. Click to step through 0.5× and 0.25× back to 1×.",
   "slow.label": "SLOW",
diff --git a/packages/gui-extensions/src/debug/renderer.tsx b/packages/gui-extensions/src/debug/renderer.tsx
index 81f5eb30ce6..fbdc210f28e 100644
--- a/packages/gui-extensions/src/debug/renderer.tsx
+++ b/packages/gui-extensions/src/debug/renderer.tsx
@@ -8,6 +8,9 @@ const setup: Setup<typeof Debug> = (ctx) => {
   // builds, prod included, drop the import and never contain knobs.
   const motionTools = import.meta.env.DEV || import.meta.env.VITE_OPENCODE_CHANNEL === "beta"
   const Motion = motionTools ? lazy(() => import("./motion")) : undefined
+  const TypePanel = motionTools ? lazy(() => import("./type-panel")) : undefined
+
+  if (motionTools) void import("./type").then((type) => type.applyStored())
   // Window-local; every window starts with the bar hidden.
   const [visible, setVisible] = createSignal(false)
 
@@ -17,6 +20,8 @@ const setup: Setup<typeof Debug> = (ctx) => {
     setVisible((value) => !value)
   }
 
+  const [typing, setTyping] = createSignal(false)
+
   const toggleMotion = () => {
     setMotion((value) => !value)
   }
@@ -41,6 +46,7 @@ const setup: Setup<typeof Debug> = (ctx) => {
             <DebugBar
               diagnostics={import.meta.env.DEV}
               motion={Motion ? { open: motion(), toggle: toggleMotion } : undefined}
+              type={TypePanel ? { open: typing(), toggle: () => setTyping((value) => !value) } : undefined}
               inline
             />
           </Suspense>
@@ -53,6 +59,13 @@ const setup: Setup<typeof Debug> = (ctx) => {
             </Suspense>
           </Show>
         )}
+        {TypePanel && (
+          <Show when={visible() && typing()}>
+            <Suspense>
+              <TypePanel title={ctx.t("type.title")} />
+            </Suspense>
+          </Show>
+        )}
       </>
     ),
   })
diff --git a/packages/gui-extensions/src/debug/type-panel.tsx b/packages/gui-extensions/src/debug/type-panel.tsx
new file mode 100644
index 00000000000..ec2d9adb352
--- /dev/null
+++ b/packages/gui-extensions/src/debug/type-panel.tsx
@@ -0,0 +1,59 @@
+import { createSignal, For } from "solid-js"
+import { Portal } from "solid-js/web"
+import { apply, load, options, save, type Type } from "./type"
+
+const groups = [
+  ["smoothing", "Smoothing"],
+  ["family", "Family"],
+  ["weight", "Weight"],
+  ["tracking", "Tracking"],
+  ["opsz", "Inter opsz"],
+] as const
+
+// The Type workspace: live text-rendering overrides, docked above the debug bar's left end. Choices persist on this device.
+export default function TypePanel(props: { title: string }) {
+  const [type, setType] = createSignal<Type>(load())
+
+  const update = (next: Type) => {
+    setType(next)
+    apply(next)
+    save(next)
+  }
+
+  return (
+    <Portal>
+      <div class="pointer-events-auto fixed bottom-10 left-3 z-50 w-[320px] rounded-xl border border-border-base bg-surface-raised-stronger-non-alpha p-3 text-12-regular text-text-strong shadow-[var(--shadow-lg-border-base)]">
+        <div class="mb-2 flex items-center justify-between">
+          <span class="font-bold">{props.title}</span>
+          <button type="button" class="rounded px-1.5 hover:bg-surface-raised-base" onClick={() => update({})}>
+            Reset
+          </button>
+        </div>
+        <For each={groups}>
+          {([name, label]) => (
+            <div class="flex items-center justify-between gap-2 py-1">
+              <span class="opacity-70">{label}</span>
+              <div class="flex gap-1">
+                <For each={[undefined, ...options[name]]}>
+                  {(value) => (
+                    <button
+                      type="button"
+                      aria-pressed={type()[name] === value}
+                      classList={{
+                        "rounded px-1.5 py-0.5 hover:bg-surface-raised-base": true,
+                        "bg-surface-raised-base font-bold": type()[name] === value,
+                      }}
+                      onClick={() => update({ ...type(), [name]: value })}
+                    >
+                      {value ?? "app"}
+                    </button>
+                  )}
+                </For>
+              </div>
+            </div>
+          )}
+        </For>
+      </div>
+    </Portal>
+  )
+}
diff --git a/packages/gui-extensions/src/debug/type.ts b/packages/gui-extensions/src/debug/type.ts
new file mode 100644
index 00000000000..693e1ece4fd
--- /dev/null
+++ b/packages/gui-extensions/src/debug/type.ts
@@ -0,0 +1,75 @@
+const key = "opencode.type.panel"
+
+export const options = {
+  smoothing: ["auto", "antialiased"],
+  family: ["inter", "system"],
+  weight: ["400", "440", "450", "500"],
+  tracking: ["0", "-0.04", "-0.1"],
+  opsz: ["auto", "none"],
+} as const
+
+export type Type = { [K in keyof typeof options]?: (typeof options)[K][number] }
+
+const css = `
+:root[data-type-smoothing], :root[data-type-smoothing] * { -webkit-font-smoothing: var(--type-smoothing) !important; }
+:root[data-type-weight] body :not(b, strong, h1, h2, h3, h4, h5, h6, th, [class*="font-bold"], [class*="font-semibold"], [class*="font-medium"], [class*="font-["]) { font-weight: var(--type-weight) !important; }
+:root[data-type-tracking] body * { letter-spacing: var(--type-tracking) !important; }
+:root[data-type-opsz] body * { font-optical-sizing: none !important; }
+`
+
+const system = '-apple-system, BlinkMacSystemFont, "SF Pro Text", system-ui, sans-serif'
+
+// Overrides are global and sit on the root, so no component changes are needed. An unset group leaves the app as shipped.
+export function apply(type: Type) {
+  const root = document.documentElement
+
+  const set = (name: string, value: string | undefined, css?: string) => {
+    if (value === undefined) {
+      root.removeAttribute(`data-type-${name}`)
+      root.style.removeProperty(`--type-${name}`)
+
+      return
+    }
+
+    root.setAttribute(`data-type-${name}`, value)
+    root.style.setProperty(`--type-${name}`, css ?? value)
+  }
+
+
+  if (!document.getElementById("type-tuning")) {
+    const style = document.createElement("style")
+    style.id = "type-tuning"
+    style.textContent = css
+    document.head.append(style)
+  }
+
+
+  set("smoothing", type.smoothing)
+  set("weight", type.weight)
+  set("tracking", type.tracking, type.tracking && `${type.tracking}px`)
+  set("opsz", type.opsz === "none" ? "none" : undefined)
+
+
+  for (const name of ["--font-family-sans", "--v2-font-family-sans"]) {
+    if (type.family === "system") root.style.setProperty(name, system)
+    else root.style.removeProperty(name)
+  }
+}
+
+export function load(): Type {
+  try {
+    return JSON.parse(localStorage.getItem(key) ?? "{}")
+  } catch {
+    return {}
+  }
+}
+
+export function save(type: Type) {
+  try {
+    localStorage.setItem(key, JSON.stringify(type))
+  } catch {}
+}
+
+export function applyStored() {
+  apply(load())
+}