From 308857c4a7d3854ff5d4b6ed9ad56244164c91b7 Mon Sep 17 00:00:00 2001
From: locphamtran <tranloclqd@gmail.com>
Date: Tue, 18 Aug 2026 09:56:53 +0700
Subject: [PATCH] fix: VST GUI embed chup frame trang (Ozone 11 GPU) - luon
 chup ca BitBlt va PrintWindow PW_RENDERFULLCONTENT, chon frame chi tiet hon;
 fix loi JPEG chi ghi hang dau tien

---
 native_bridge/src/FxGuiServer.cpp | 53 +++++++++++++++++++------------
 1 file changed, 33 insertions(+), 20 deletions(-)

diff --git a/native_bridge/src/FxGuiServer.cpp b/native_bridge/src/FxGuiServer.cpp
index 9366556..6e914be 100644
--- a/native_bridge/src/FxGuiServer.cpp
+++ b/native_bridge/src/FxGuiServer.cpp
@@ -128,9 +128,11 @@ void sendResponse(SOCKET c, int code, const char* contentType,
 }
 
 // --- frame capture -----------------------------------------------------------
-// BitBlt the window client rect; if the result is all-black (plugin uses a
-// layered/DirectX surface GDI cannot see), fall back to PrintWindow with
-// PW_RENDERFULLCONTENT. Returns JPEG bytes in `out`.
+// Capture the window client rect twice — BitBlt (GDI view) and PrintWindow
+// with PW_RENDERFULLCONTENT (DWM composition, includes DirectX/GPU surfaces
+// that GDI cannot see) — and keep the frame with more visual detail. Ozone 11
+// and other GPU-rendered plugins paint WHITE into the GDI DC, so the old
+// all-black fallback never fired and a white frame was served. Returns JPEG.
 bool captureHwndToJpeg(HWND hwnd, std::vector<unsigned char>& out, int quality) {
     RECT rc;
     if (!GetClientRect(hwnd, &rc)) return false;
@@ -143,8 +145,8 @@ bool captureHwndToJpeg(HWND hwnd, std::vector<unsigned char>& out, int quality)
     HBITMAP bmp = CreateCompatibleBitmap(win, w, h);
     HGDIOBJ oldBmp = SelectObject(mem, bmp);
 
-    std::vector<unsigned char> px((size_t)w * h * 4);
-    auto grab = [&]() -> bool {
+    std::vector<unsigned char> pxB((size_t)w * h * 4), pxP((size_t)w * h * 4);
+    auto grabInto = [&](unsigned char* p) -> bool {
         BITMAPINFO bi = {};
         bi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
         bi.bmiHeader.biWidth = w;
@@ -152,29 +154,37 @@ bool captureHwndToJpeg(HWND hwnd, std::vector<unsigned char>& out, int quality)
         bi.bmiHeader.biPlanes = 1;
         bi.bmiHeader.biBitCount = 32;
         bi.bmiHeader.biCompression = BI_RGB;
-        return GetDIBits(mem, bmp, 0, h, px.data(), &bi, DIB_RGB_COLORS) == h;
+        return GetDIBits(mem, bmp, 0, h, p, &bi, DIB_RGB_COLORS) == h;
     };
-    auto isAllBlack = [&]() -> bool {
-        // Sample a coarse grid of pixels; all zero => invisible to GDI.
-        const int step = 8;
+    auto detailScore = [&](const unsigned char* p) -> long long {
+        // Count sampled pixels that are neither near-black nor near-white.
+        // GPU-rendered plugins (Ozone 11, ...) are invisible to GDI: BitBlt
+        // yields a white/black-strip frame with ~2 distinct values, while the
+        // real UI has many mid-grey levels. Pick the frame with more detail.
+        long long d = 0;
+        const int step = 4;
         for (int y = 0; y < h; y += step)
             for (int x = 0; x < w; x += step) {
                 const size_t i = ((size_t)y * w + x) * 4;
-                if (px[i] || px[i + 1] || px[i + 2]) return false;
+                const unsigned lum = ((unsigned)p[i] * 77u + (unsigned)p[i + 1] * 150u + (unsigned)p[i + 2] * 29u) >> 8;
+                if (lum >= 28 && lum <= 232) ++d;  // exclude near-black/white
             }
-        return true;
+        return d;
     };
 
-    bool ok = BitBlt(mem, 0, 0, w, h, win, 0, 0, SRCCOPY | CAPTUREBLT) != 0 && grab();
-    if (ok && isAllBlack()) {
-        ok = PrintWindow(hwnd, mem, PW_RENDERFULLCONTENT) != 0 && grab();
-    }
-
+    bool okB = BitBlt(mem, 0, 0, w, h, win, 0, 0, SRCCOPY | CAPTUREBLT) != 0 && grabInto(pxB.data());
+    // PW_RENDERFULLCONTENT asks DWM to compose the window (includes child
+    // windows + DirectX surfaces) — the only way to see GPU-rendered editors.
+    bool okP = PrintWindow(hwnd, mem, PW_RENDERFULLCONTENT) != 0 && grabInto(pxP.data());
+    unsigned char* px = nullptr;
+    if (okB && okP) px = detailScore(pxP.data()) > detailScore(pxB.data()) ? pxP.data() : pxB.data();
+    else if (okP) px = pxP.data();
+    else if (okB) px = pxB.data();
     SelectObject(mem, oldBmp);
     DeleteObject(bmp);
     DeleteDC(mem);
     ReleaseDC(hwnd, win);
-    if (!ok) return false;
+    if (!px) return false;
 
     // BGRA (GDI) -> RGB, then JPEG.
     std::vector<unsigned char> rgb((size_t)w * h * 3);
@@ -198,9 +208,12 @@ bool captureHwndToJpeg(HWND hwnd, std::vector<unsigned char>& out, int quality)
     jpeg_set_defaults(&cinfo);
     jpeg_set_quality(&cinfo, quality, TRUE);
     jpeg_start_compress(&cinfo, TRUE);
-    JSAMPROW row = rgb.data();
-    while (cinfo.next_scanline < cinfo.image_height)
-        jpeg_write_scanlines(&cinfo, &row, 1);
+    JSAMPROW rows[1];
+    rows[0] = rgb.data();
+    while (cinfo.next_scanline < cinfo.image_height) {
+        jpeg_write_scanlines(&cinfo, rows, 1);
+        rows[0] += (size_t)w * 3;
+    }
     jpeg_finish_compress(&cinfo);
     if (memBuf && memSize > 0) out.assign(memBuf, memBuf + memSize);
     std::free(memBuf);