From cef378b0a3a18aea04fd1dd2b3762525e15a1878 Mon Sep 17 00:00:00 2001
From: nanahi <130121847+na-na-hi@users.noreply.github.com>
Date: Tue, 2 Jan 2024 16:24:41 -0500
Subject: [PATCH] w32_common: add function to control window transparency state

Use the DWM API to enable and disable compositor transparency.
---
 video/out/w32_common.c | 21 +++++++++++++++++++++
 video/out/w32_common.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/video/out/w32_common.c b/video/out/w32_common.c
index 683ee747aa..4f2e6f0e1e 100644
--- a/video/out/w32_common.c
+++ b/video/out/w32_common.c
@@ -2245,3 +2245,24 @@ void vo_w32_run_on_thread(struct vo *vo, void (*cb)(void *ctx), void *ctx)
     struct vo_w32_state *w32 = vo->w32;
     mp_dispatch_run(w32->dispatch, cb, ctx);
 }
+
+void vo_w32_set_transparency(struct vo *vo, bool enable)
+{
+    struct vo_w32_state *w32 = vo->w32;
+    if (w32->parent)
+        return;
+
+    DWM_BLURBEHIND dbb = {0};
+    if (enable) {
+        HRGN rgn = CreateRectRgn(0, 0, -1, -1);
+        dbb.dwFlags = DWM_BB_ENABLE | DWM_BB_BLURREGION;
+        dbb.hRgnBlur = rgn;
+        dbb.fEnable = TRUE;
+        DwmEnableBlurBehindWindow(w32->window, &dbb);
+        DeleteObject(rgn);
+    } else {
+        dbb.dwFlags = DWM_BB_ENABLE;
+        dbb.fEnable = FALSE;
+        DwmEnableBlurBehindWindow(w32->window, &dbb);
+    }
+}
diff --git a/video/out/w32_common.h b/video/out/w32_common.h
index 528b21662c..bc22a2d3e0 100644
--- a/video/out/w32_common.h
+++ b/video/out/w32_common.h
@@ -32,5 +32,6 @@ int vo_w32_control(struct vo *vo, int *events, int request, void *arg);
 void vo_w32_config(struct vo *vo);
 HWND vo_w32_hwnd(struct vo *vo);
 void vo_w32_run_on_thread(struct vo *vo, void (*cb)(void *ctx), void *ctx);
+void vo_w32_set_transparency(struct vo *vo, bool enable);
 
 #endif /* MPLAYER_W32_COMMON_H */