端末を熱くしないライブ壁紙 — WallpaperService の描画ループを電力予算から設計する

class SkyWallpaperService : WallpaperService() {
    override fun onCreateEngine(): Engine = SkyEngine()
 
    inner class SkyEngine : Engine(), Choreographer.FrameCallback {
        private val choreographer = Choreographer.getInstance()
        private var visible = false
        private var scheduled = false
        private val renderer = SkyRenderer()
 
        // 可視性ゲート: 見えているときだけフレームを要求する
        override fun onVisibilityChanged(v: Boolean) {
            visible = v
            if (v) requestFrame() else stop()
        }
 
        override fun onSurfaceDestroyed(holder: SurfaceHolder) {
            stop()
            super.onSurfaceDestroyed(holder)
        }
 
        private fun requestFrame() {
            if (visible && !scheduled) {
                scheduled = true
                choreographer.postFrameCallback(this)
            }
        }
 
        private fun stop() {
            scheduled = false
            choreographer.removeFrameCallback(this)
        }
 
        override fun doFrame(frameTimeNanos: Long) {
            scheduled = false
            if (!visible) return
 
            val dirty = renderer.advance(frameTimeNanos) // 変化があったか
            if (dirty) drawOnce()
 
            // アイドルゲート: 変化がある間だけ次フレームを繋ぐ
            if (renderer.isAnimating) requestFrame()
        }
 
        private fun drawOnce() {
            val holder = surfaceHolder
            var canvas: Canvas? = null
            try {
                canvas = holder.lockHardwareCanvas()
                renderer.render(canvas)
            } finally {
                if (canvas != null) holder.unlockCanvasAndPost(canvas)
            }
        }
    }
}

class FramePacer(private val power: PowerManager) {
    // 目標fpsごとに「何ナノ秒空けるか」を持つ
    private var minIntervalNanos = nanosFor(60)
    private var lastDrawNanos = 0L
 
    fun onThermalStatus(status: Int) {
        val targetFps = when {
            status >= PowerManager.THERMAL_STATUS_SEVERE  -> 10
            status >= PowerManager.THERMAL_STATUS_MODERATE -> 30
            else -> 60
        }
        minIntervalNanos = nanosFor(targetFps)
    }
 
    fun onBatterySaver(enabled: Boolean) {
        if (enabled) minIntervalNanos = maxOf(minIntervalNanos, nanosFor(15))
    }
 
    // このフレームで実描画してよいか
    fun shouldDraw(frameTimeNanos: Long): Boolean {
        if (frameTimeNanos - lastDrawNanos < minIntervalNanos) return false
        lastDrawNanos = frameTimeNanos
        return true
    }
 
    private fun nanosFor(fps: Int): Long = 1_000_000_000L / fps
}

# エージェントに渡した計測スクリプトの中核（1条件ぶん）
adb shell dumpsys batterystats --reset
adb shell settings put system screen_off_timeout 3600000
adb shell input keyevent KEYCODE_WAKEUP
 
# 壁紙をプレビュー適用して所定時間放置
adb shell am start -a android.service.wallpaper.CHANGE_LIVE_WALLPAPER \
  --es android.service.wallpaper.extra.LIVE_WALLPAPER_COMPONENT \
  "com.dolice.sky/.SkyWallpaperService"
sleep 1800
 
# プロセス別の消費を抽出してJSON化
adb shell dumpsys batterystats --charged com.dolice.sky \
  | grep -E "Uid .* com.dolice.sky|Foreground|Wake lock" > "run_${1}.txt"