From 0d30fa6cc736ee91217d7a47a2efd2a07258720c Mon Sep 17 00:00:00 2001
From: Joachim Bauch <bauch@struktur.de>
Date: Mon, 8 Jul 2024 10:17:52 +0200
Subject: [PATCH] dec265: Resize window if image resolution changes mid-stream.

---
 dec265/dec265.cc | 18 +++++++++--------
 dec265/sdl.cc    | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
 dec265/sdl.hh    |  1 +
 3 files changed, 63 insertions(+), 8 deletions(-)

diff --git a/dec265/dec265.cc b/dec265/dec265.cc
index 79f67cd3..5ccd2c1d 100644
--- a/dec265/dec265.cc
+++ b/dec265/dec265.cc
@@ -266,17 +266,19 @@ bool display_sdl(const struct de265_image* img)
 
   de265_chroma chroma = de265_get_chroma_format(img);
 
+  enum SDL_YUV_Display::SDL_Chroma sdlChroma;
+  switch (chroma) {
+  case de265_chroma_420:  sdlChroma = SDL_YUV_Display::SDL_CHROMA_420;  break;
+  case de265_chroma_422:  sdlChroma = SDL_YUV_Display::SDL_CHROMA_422;  break;
+  case de265_chroma_444:  sdlChroma = SDL_YUV_Display::SDL_CHROMA_444;  break;
+  case de265_chroma_mono: sdlChroma = SDL_YUV_Display::SDL_CHROMA_MONO; break;
+  }
+
   if (!sdl_active) {
     sdl_active=true;
-    enum SDL_YUV_Display::SDL_Chroma sdlChroma;
-    switch (chroma) {
-    case de265_chroma_420:  sdlChroma = SDL_YUV_Display::SDL_CHROMA_420;  break;
-    case de265_chroma_422:  sdlChroma = SDL_YUV_Display::SDL_CHROMA_422;  break;
-    case de265_chroma_444:  sdlChroma = SDL_YUV_Display::SDL_CHROMA_444;  break;
-    case de265_chroma_mono: sdlChroma = SDL_YUV_Display::SDL_CHROMA_MONO; break;
-    }
-
     sdlWin.init(width,height, sdlChroma);
+  } else {
+    sdlWin.resize(width,height, sdlChroma);
   }
 
   int stride,chroma_stride;
diff --git a/dec265/sdl.cc b/dec265/sdl.cc
index eab1f8f1..b91278eb 100644
--- a/dec265/sdl.cc
+++ b/dec265/sdl.cc
@@ -94,6 +94,58 @@ bool SDL_YUV_Display::init(int frame_width, int frame_height, enum SDL_Chroma ch
   return true;
 }
 
+bool SDL_YUV_Display::resize(int frame_width, int frame_height, enum SDL_Chroma chroma)
+{
+  // reduce image size to a multiple of 8 (apparently required by YUV overlay)
+
+  frame_width  &= ~7;
+  frame_height &= ~7;
+
+  if (frame_width == rect.w && frame_height == rect.h && mChroma == chroma) {
+    return true;
+  }
+
+  SDL_SetWindowSize(mWindow, frame_width, frame_height);
+  SDL_DestroyTexture(mTexture);
+  SDL_DestroyRenderer(mRenderer);
+
+  Uint32 flags = 0;  // Empty flags prioritize SDL_RENDERER_ACCELERATED.
+  mRenderer = SDL_CreateRenderer(mWindow, -1, flags);
+  if (!mRenderer) {
+    printf("SDL: Couldn't create renderer: %s\n", SDL_GetError());
+    SDL_Quit();
+    return false;
+  }
+
+  Uint32 pixelFormat = 0;
+  switch (mChroma) {
+  case SDL_CHROMA_MONO: pixelFormat = SDL_PIXELFORMAT_YV12; break;
+  case SDL_CHROMA_420:  pixelFormat = SDL_PIXELFORMAT_YV12; break;
+  case SDL_CHROMA_422:  pixelFormat = SDL_PIXELFORMAT_YV12; break;
+  case SDL_CHROMA_444:  pixelFormat = SDL_PIXELFORMAT_YV12; break;
+  //case SDL_CHROMA_444:  pixelFormat = SDL_PIXELFORMAT_YV12; break;
+  default:
+    printf("Unsupported chroma: %d\n", mChroma);
+    SDL_Quit();
+    return false;
+  }
+
+  mTexture = SDL_CreateTexture(mRenderer, pixelFormat,
+    SDL_TEXTUREACCESS_STREAMING, frame_width, frame_height);
+  if (!mTexture ) {
+    printf("SDL: Couldn't create SDL texture: %s\n", SDL_GetError());
+    SDL_Quit();
+    return false;
+  }
+
+  mChroma = chroma;
+
+  rect.w = frame_width;
+  rect.h = frame_height;
+
+  return true;
+}
+
 void SDL_YUV_Display::display(const unsigned char *Y,
                               const unsigned char *U,
                               const unsigned char *V,
diff --git a/dec265/sdl.hh b/dec265/sdl.hh
index f94aad66..1d020b65 100644
--- a/dec265/sdl.hh
+++ b/dec265/sdl.hh
@@ -39,6 +39,7 @@ public:
   };
 
   bool init(int frame_width, int frame_height, enum SDL_Chroma chroma = SDL_CHROMA_420);
+  bool resize(int frame_width, int frame_height, enum SDL_Chroma chroma = SDL_CHROMA_420);
   void display(const unsigned char *Y, const unsigned char *U, const unsigned char *V,
                int stride, int chroma_stride);
   void close();