[libcamera-devel] [PATCH v8 4/4] cam: sdl_sink: Add MJPG support to SDL sink

[Eric Curtin]

So we have at least two supported capturing pixel formats (although
many possible output pixel formats thanks to SDL conversion). MJPG
support only built in if SDL2_image is available, provides
decompression.

Signed-off-by: Eric Curtin <ecurtin at redhat.com>
---
 src/cam/meson.build          |  9 +++++++++
 src/cam/sdl_sink.cpp         |  9 +++++++++
 src/cam/sdl_texture_mjpg.cpp | 18 ++++++++++++++++++
 src/cam/sdl_texture_mjpg.h   | 10 ++++++++++
 4 files changed, 46 insertions(+)
 create mode 100644 src/cam/sdl_texture_mjpg.cpp
 create mode 100644 src/cam/sdl_texture_mjpg.h

diff --git a/src/cam/meson.build b/src/cam/meson.build
index 3032730b..afc0ea9f 100644
--- a/src/cam/meson.build
+++ b/src/cam/meson.build
@@ -41,6 +41,14 @@ if libsdl2.found()
         'sdl_texture.cpp',
         'sdl_texture_yuyv.cpp'
     ])
+
+    libsdl2_image = dependency('SDL2_image', required : false)
+    if libsdl2.found()
+        cam_cpp_args += ['-DHAVE_SDL_IMAGE']
+        cam_sources += files([
+            'sdl_texture_mjpg.cpp'
+        ])
+    endif
 endif
 
 cam  = executable('cam', cam_sources,
@@ -49,6 +57,7 @@ cam  = executable('cam', cam_sources,
                       libcamera_public,
                       libdrm,
                       libsdl2,
+                      libsdl2_image,
                       libevent,
                   ],
                   cpp_args : cam_cpp_args,
diff --git a/src/cam/sdl_sink.cpp b/src/cam/sdl_sink.cpp
index 6fbeaf56..f15c01cb 100644
--- a/src/cam/sdl_sink.cpp
+++ b/src/cam/sdl_sink.cpp
@@ -19,6 +19,10 @@
 
 #include "sdl_texture_yuyv.h"
 
+#ifdef HAVE_SDL_IMAGE
+#include "sdl_texture_mjpg.h"
+#endif
+
 #include "event_loop.h"
 #include "image.h"
 
@@ -59,6 +63,11 @@ int SDLSink::configure(const libcamera::CameraConfiguration &config)
 	case libcamera::formats::YUYV:
 		sdlTexture_ = std::make_unique<SDLTextureYUYV>(sdlRect_);
 		break;
+#ifdef HAVE_SDL_IMAGE
+	case libcamera::formats::MJPEG:
+		sdlTexture_ = std::make_unique<SDLTextureMJPG>(sdlRect_);
+		break;
+#endif
 	default:
 		std::cerr << "Unsupported pixel format "
 			  << cfg.pixelFormat.toString() << std::endl;
diff --git a/src/cam/sdl_texture_mjpg.cpp b/src/cam/sdl_texture_mjpg.cpp
new file mode 100644
index 00000000..636fdbea
--- /dev/null
+++ b/src/cam/sdl_texture_mjpg.cpp
@@ -0,0 +1,18 @@
+#include "sdl_texture_mjpg.h"
+
+#include <SDL2/SDL_image.h>
+
+using namespace libcamera;
+
+SDLTextureMJPG::SDLTextureMJPG(const SDL_Rect &sdlRect)
+	: SDLTexture(sdlRect, SDL_PIXELFORMAT_RGB24, 0)
+{
+}
+
+void SDLTextureMJPG::update(const Span<uint8_t> &data)
+{
+	SDL_RWops *buffer_stream = SDL_RWFromMem(data.data(), data.size());
+	SDL_Surface *frame = IMG_Load_RW(buffer_stream, 0);
+	SDL_UpdateTexture(ptr_, NULL, frame->pixels, frame->pitch);
+	SDL_FreeSurface(frame);
+}
diff --git a/src/cam/sdl_texture_mjpg.h b/src/cam/sdl_texture_mjpg.h
new file mode 100644
index 00000000..fefaaeeb
--- /dev/null
+++ b/src/cam/sdl_texture_mjpg.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include "sdl_texture.h"
+
+class SDLTextureMJPG : public SDLTexture
+{
+public:
+	SDLTextureMJPG(const SDL_Rect &sdlRect);
+	void update(const libcamera::Span<uint8_t> &data) override;
+};
-- 
2.35.1