app+docs: 第三十八轮追加——同帧对照收敛差距：真机显示与 NUC dump 空间相关 0.994，鲁棒同口径下 COL 0.33 vs 官方 0.28 达标、ROW 0.22 vs 0.10 差 2.2×；640 中间级竖屏 2.25× 非整数致 GPU 列交替恶化已回退（保留 nativeOut 单级 9×/16× 整数）；PIL F-mode resize 失真教训与 COL 波动待验项入档

android/app/src/main/kotlin/com/mag160c/thermal/ui/live/LiveRenderer.kt

@@ -100,24 +100,6 @@ class LiveRenderer(
         return true
     }
 
-    /**
-     * 640x480 offscreen stage, mirroring the official viewer's display chain:
-     * jadx `ImageViewer` draws the 160x120 SDK bitmap into a 640x480 offscreen
-     * bitmap with the filtering paint (PaintFlagsDrawFilter + FILTER_BITMAP) and
-     * only the SCREEN scales that further. The intermediate 4x bilinear is what
-     * attenuates the per-sensor-row FPN pattern on the screen (measured, §17:
-     * with it the row pattern lands on the official's 0.12e-2 arc; without, our
-     * single-scale render shows it at full amplitude). The stage costs one GPU
-     * blit per frame.
-     */
-    private var mid: Bitmap? = null
-    private val midRect = android.graphics.RectF(0f, 0f, 640f, 480f)
-
-    private fun ensureMid(): Bitmap {
-        mid?.let { return it }
-        return Bitmap.createBitmap(640, 480, Bitmap.Config.ARGB_8888).also { mid = it }
-    }
-
 
     private companion object {
         const val BAR_SEGMENTS = 96
@@ -234,12 +216,10 @@ class LiveRenderer(
 
         val zoom = vm.state.value.zoom
         val crop = ImageTransform.cropForZoom(zoom)
-        // The zoom source rect now addresses the 640x480 middle stage (4x the
-        // buffer coordinates), exactly like the official viewer's offscreen.
         val src: android.graphics.Rect? = if (zoom > 1) {
-            val cw = (640 * (crop[2] - crop[0])).toInt()
-            val ch = (480 * (crop[3] - crop[1])).toInt()
-            srcRect.set(320 - cw / 2, 240 - ch / 2, 320 + cw / 2, 240 + ch / 2)
+            val cw = (bufW * (crop[2] - crop[0])).toInt()
+            val ch = (bufH * (crop[3] - crop[1])).toInt()
+            srcRect.set(bufW / 2 - cw / 2, bufH / 2 - ch / 2, bufW / 2 + cw / 2, bufH / 2 + ch / 2)
             srcRect
         } else null
 
@@ -254,14 +234,15 @@ class LiveRenderer(
             fit.cx - size[0] / 2f, fit.cy - size[1] / 2f,
             fit.cx + size[0] / 2f, fit.cy + size[1] / 2f,
         )
-        // two-step display like the official viewer: buffer -> 640x480 (filtered)
-        // -> screen. The GPU blits are cheap; the attenuated row pattern is the point.
-        val m = ensureMid()
-        val mc = Canvas(m)
-        mc.drawColor(Color.BLACK)
-        mc.drawBitmap(bitmap, null, midRect, paint)
-        if (src != null) canvas.drawBitmap(m, src, dstRect, paint)
-        else canvas.drawBitmap(m, null, dstRect, paint)
+        // Single filtered scale buffer -> screen. The official viewer's 640x480
+        // offscreen stage was tried (round 38) and REVERTED: in our portrait
+        // fitRect the second stage lands on a 2.25x non-integer scale, and the
+        // GPU's rendering of it measurably WORSENED the column-direction
+        // alternation on the device (0.33 -> 0.55 x1e-2 arc) — an artifact the
+        // official (landscape, integer 3x second stage) doesn't have. The 160x120
+        // -> 1440x1920 single scale is 9x/16x integer, artifact-free.
+        if (src != null) canvas.drawBitmap(bitmap, src, dstRect, paint)
+        else canvas.drawBitmap(bitmap, null, dstRect, paint)
         canvas.restore()
 
         drawOsd(canvas, vm.state.value)