Fix: tauri window scaling bug

crates/sprimo-tauri/capabilities/default.json

@@ -6,6 +6,10 @@
   "permissions": [
     "core:default",
     "core:window:allow-start-dragging",
+    "core:window:allow-set-size",
+    "core:window:allow-set-position",
+    "core:window:allow-inner-size",
+    "core:window:allow-outer-position",
     "core:event:allow-listen",
     "core:event:allow-unlisten"
   ]

crates/sprimo-tauri/gen/schemas/capabilities.json

@@ -1 +1 @@
-{"default":{"identifier":"default","description":"Default capability for sprimo-tauri main window runtime APIs.","local":true,"windows":["*"],"permissions":["core:default","core:window:allow-start-dragging","core:event:allow-listen","core:event:allow-unlisten"]}}
+{"default":{"identifier":"default","description":"Default capability for sprimo-tauri main window runtime APIs.","local":true,"windows":["*"],"permissions":["core:default","core:window:allow-start-dragging","core:window:allow-set-size","core:window:allow-set-position","core:window:allow-inner-size","core:window:allow-outer-position","core:event:allow-listen","core:event:allow-unlisten"]}}

docs/IMPLEMENTATION_STATUS.md

@@ -19,7 +19,7 @@ Date: 2026-02-12
 | Random backend API tester | Implemented | `scripts/random_backend_tester.py` with `just random-backend-test` and strict variant |
 | QA/documentation workflow | Implemented | `docs/QA_WORKFLOW.md`, issue/evidence templates, and `scripts/qa_validate.py` with `just qa-validate` |
 | Shared runtime core | In progress | `sprimo-runtime-core` extracted with shared config/snapshot/API startup and command application |
-| Tauri alternative frontend | In progress | `sprimo-tauri` now runs runtime-core/API + PixiJS sprite rendering shell, parity work remains |
+| Tauri alternative frontend | In progress | `sprimo-tauri` now runs runtime-core/API + PixiJS sprite rendering shell; scale updates now auto-fit window to avoid top clipping |
 | Tauri runtime testing workflow | Implemented | `docs/TAURI_RUNTIME_TESTING.md` defines strict workspace testing; packaged mode pending packaging support |
 
 ## Next Major Gaps

docs/RELEASE_TESTING.md

@@ -121,6 +121,9 @@ Authoritative workflow: `docs/TAURI_RUNTIME_TESTING.md`.
 8. Run randomized backend API interaction:
 - `just random-backend-test`
 - verify command traffic remains stable and runtime stays alive.
+9. Verify scale-fit behavior in tauri runtime:
+- send `SetTransform.scale` values above `1.0`
+- confirm full sprite remains visible and window auto-resizes without top clipping
 
 ### Packaged Mode (Required Once Tauri Packaging Exists)
 

docs/TAURI_RUNTIME_TESTING.md

@@ -62,7 +62,9 @@ An issue touching Tauri runtime behaviors must satisfy all requirements before `
 2. Verify sprite renders in the tauri window.
 3. Verify animation advances over time.
 4. Send `PlayAnimation` command and verify clip switch is reflected.
-5. Send `SetTransform.scale` and verify rendered sprite scale changes.
+5. Send `SetTransform.scale` and verify rendered sprite scale changes without clipping:
+- at `scale >= 1.0`, full sprite remains visible (no missing upper region)
+- runtime auto-fits window size to sprite frame size and keeps bottom-center visually stable
 6. Verify missing animation fallback:
 - unknown animation name falls back to `idle` or first available clip.
 7. Verify sprite-pack loading:

frontend/tauri-ui/src/main.tsx

@@ -2,19 +2,60 @@ import React from "react";
 import ReactDOM from "react-dom/client";
 import { invoke } from "@tauri-apps/api/core";
 import { listen } from "@tauri-apps/api/event";
-import { getCurrentWindow } from "@tauri-apps/api/window";
+import { LogicalPosition, LogicalSize, getCurrentWindow } from "@tauri-apps/api/window";
 import { PixiPetRenderer, type UiSpritePack, type UiSnapshot } from "./renderer/pixi_pet";
 import "./styles.css";
 
+const WINDOW_PADDING = 16;
+const MIN_WINDOW_SIZE = 64;
+const SIZE_EPSILON = 0.5;
+const SCALE_EPSILON = 0.0001;
+
+function fittedWindowSize(
+  frameWidth: number,
+  frameHeight: number,
+  scale: number
+): { width: number; height: number } {
+  const safeScale = Number.isFinite(scale) && scale > 0 ? scale : 1;
+  const width = Math.max(frameWidth * safeScale + WINDOW_PADDING, MIN_WINDOW_SIZE);
+  const height = Math.max(frameHeight * safeScale + WINDOW_PADDING, MIN_WINDOW_SIZE);
+  return { width, height };
+}
+
+async function fitWindowForScale(pack: UiSpritePack, scale: number): Promise<void> {
+  const window = getCurrentWindow();
+  const [outerPosition, innerSize] = await Promise.all([
+    window.outerPosition(),
+    window.innerSize()
+  ]);
+
+  const target = fittedWindowSize(pack.frame_width, pack.frame_height, scale);
+  const widthChanged = Math.abs(target.width - innerSize.width) > SIZE_EPSILON;
+  const heightChanged = Math.abs(target.height - innerSize.height) > SIZE_EPSILON;
+  if (!widthChanged && !heightChanged) {
+    return;
+  }
+
+  const deltaWidth = target.width - innerSize.width;
+  const deltaHeight = target.height - innerSize.height;
+  const targetX = outerPosition.x - deltaWidth / 2;
+  const targetY = outerPosition.y - deltaHeight;
+
+  await window.setSize(new LogicalSize(target.width, target.height));
+  await window.setPosition(new LogicalPosition(targetX, targetY));
+}
+
 function App(): JSX.Element {
   const [snapshot, setSnapshot] = React.useState<UiSnapshot | null>(null);
   const [error, setError] = React.useState<string | null>(null);
   const hostRef = React.useRef<HTMLDivElement | null>(null);
   const rendererRef = React.useRef<PixiPetRenderer | null>(null);
+  const scaleFitRef = React.useRef<number | null>(null);
 
   React.useEffect(() => {
     let unlisten: null | (() => void) = null;
     let mounted = true;
+    let activePack: UiSpritePack | null = null;
     Promise.all([
       invoke<UiSpritePack>("load_active_sprite_pack"),
       invoke<UiSnapshot>("current_state")
@@ -23,6 +64,7 @@ function App(): JSX.Element {
         if (!mounted) {
           return;
         }
+        activePack = pack;
         setSnapshot(initialSnapshot);
         if (hostRef.current !== null) {
           rendererRef.current = await PixiPetRenderer.create(
@@ -31,6 +73,9 @@ function App(): JSX.Element {
             initialSnapshot
           );
         }
+        scaleFitRef.current = initialSnapshot.scale;
+        await fitWindowForScale(pack, initialSnapshot.scale);
+
         unlisten = await listen<UiSnapshot>("runtime:snapshot", (event) => {
           if (!mounted) {
             return;
@@ -38,6 +83,21 @@ function App(): JSX.Element {
           const value = event.payload;
           setSnapshot(value);
           rendererRef.current?.applySnapshot(value);
+          if (activePack === null) {
+            return;
+          }
+          if (
+            scaleFitRef.current !== null &&
+            Math.abs(scaleFitRef.current - value.scale) < SCALE_EPSILON
+          ) {
+            return;
+          }
+          scaleFitRef.current = value.scale;
+          void fitWindowForScale(activePack, value.scale).catch((err) => {
+            if (mounted) {
+              setError(String(err));
+            }
+          });
         });
       })
       .catch((err) => {

frontend/tauri-ui/src/renderer/pixi_pet.ts

@@ -75,10 +75,10 @@ export class PixiPetRenderer {
     }
     const sprite = new Sprite();
     sprite.anchor.set(pack.anchor.x, pack.anchor.y);
-    sprite.position.set(app.renderer.width / 2, app.renderer.height);
     app.stage.addChild(sprite);
 
     const renderer = new PixiPetRenderer(app, sprite, pack, baseTexture);
+    renderer.layoutSprite();
     renderer.applySnapshot(snapshot);
     renderer.startTicker();
     return renderer;
@@ -145,10 +145,12 @@ export class PixiPetRenderer {
       this.applyFrameTexture(this.currentClip.frames[0] ?? 0);
     }
     this.sprite.scale.set(snapshot.scale);
+    this.layoutSprite();
   }
 
   private startTicker(): void {
     this.app.ticker.add((ticker) => {
+      this.layoutSprite();
       const frameMs = 1000 / Math.max(this.currentClip.fps, 1);
       this.frameElapsedMs += ticker.deltaMS;
       if (this.frameElapsedMs < frameMs) {
@@ -169,6 +171,10 @@ export class PixiPetRenderer {
     });
   }
 
+  private layoutSprite(): void {
+    this.sprite.position.set(this.app.renderer.width / 2, this.app.renderer.height);
+  }
+
   private resolveClip(name: string): UiAnimationClip {
     return (
       this.animationMap.get(name) ??