treewide: add Wayland and SDL2 backends

README.md

@@ -56,6 +56,9 @@ On distributions based on systemd, `unl0kr` can be used as a [password agent](ht
 # systemd-ask-password --no-tty # Unl0kr is started
 ```
 
+**Note**: SDL2 can be used as display backend for development purposes by setting the Meson option `developer` and use `backend=sdl` in the configuration file.
+Other uses besides development are not supported by Buffybox.
+
 ## Packaging
 
 Create a full package:

f0rmz/README.md

@@ -115,6 +115,7 @@ hostname=mydevice
 - [libinput] - Input device handling  
 - [libudev] - Device enumeration
 - [libxkbcommon] - Keyboard layout support
+- [libdrm] - DRM backend
 - evdev kernel module
 
 ## Backends

f0rmz/lv_conf.h

@@ -1159,7 +1159,8 @@
  *==================*/
 
 /** Use SDL to open window on PC and handle mouse and keyboard. */
-#define LV_USE_SDL              0
+// LV_USE_SDL is defined dynamically via meson.build so we must not define it here
+// #define LV_USE_SDL              0
 #if LV_USE_SDL
     #define LV_SDL_INCLUDE_PATH     <SDL2/SDL.h>
     #define LV_SDL_RENDER_MODE      LV_DISPLAY_RENDER_MODE_DIRECT   /**< LV_DISPLAY_RENDER_MODE_DIRECT is recommended for best performance */
@@ -1231,6 +1232,7 @@
 #endif
 
 /** Driver for /dev/dri/card */
+// LV_USE_LINUX_DRM is defined dynamically via meson.build so we must not define it here
 //#define LV_USE_LINUX_DRM        0
 
 #if LV_USE_LINUX_DRM

f0rmz/meson.build

@@ -23,6 +23,13 @@ else
     f0rmz_args += '-DLV_USE_LINUX_DRM=0'
 endif
 
+if deplibsdl.found()
+    f0rmz_dependencies += deplibsdl
+    f0rmz_args += '-DLV_USE_SDL=1'
+else
+    f0rmz_args += '-DLV_USE_SDL=0'
+endif
+
 executable('f0rmz',
     include_directories: common_include_dirs,
     sources: f0rmz_sources + shared_sources + shared_sources_ul_f0 + squeek2lvgl_sources + lvgl_sources,

meson.build

@@ -14,6 +14,7 @@ depinih      = dependency('inih')
 deplibinput  = dependency('libinput')
 deplibudev   = dependency('libudev')
 depxkbcommon = dependency('xkbcommon') # For unl0kr and f0rmz only
+deplibsdl = dependency('sdl2', required: get_option('developer'))
 
 if get_option('man')
     depscdoc = dependency('scdoc', native: true)

meson_options.txt

@@ -1,4 +1,5 @@
 option('with-drm', type: 'feature', value: 'auto', description: 'Enable DRM backend')
+option('developer', type: 'feature', value: 'auto', description: 'Enable developer features')
 option('man', type: 'boolean', value: true, description: 'Install manual pages')
 option('systemd-buffyboard-service', type: 'feature', value: 'auto', description: 'Install systemd service file for buffyboard')
 option('systemd-password-agent', type: 'feature', value: 'auto', description: 'Build a systemd password agent for touchscreens')

shared/backends.c

@@ -16,6 +16,9 @@ static const char *backends[] = {
 #endif
 #if LV_USE_LINUX_DRM
     "drm",
+#endif
+#if LV_USE_SDL
+    "sdl",
 #endif
     NULL
 };

shared/backends.h

@@ -9,7 +9,7 @@
 
 #include "lv_conf.h"
 
-#if LV_USE_LINUX_FBDEV == 0 && LV_USE_LINUX_DRM == 0
+#if LV_USE_LINUX_FBDEV == 0 && LV_USE_LINUX_DRM == 0 && LV_USE_SDL == 0
 #error Neither of graphical backends is enabled
 #endif
 
@@ -26,6 +26,9 @@ typedef enum {
 #if LV_USE_LINUX_DRM
     BBX_BACKENDS_BACKEND_DRM,
 #endif
+#if LV_USE_SDL
+    BBX_BACKENDS_BACKEND_SDL,
+#endif
 } bbx_backends_backend_id_t;
 
 /**

shared/display.c

@@ -63,6 +63,17 @@ lv_display_t *bbx_display_create(bbx_backends_backend_id_t backend_id, bbx_displ
         break;
 #endif /* LV_USE_LINUX_DRM */
 
+#if LV_USE_SDL
+    case BBX_BACKENDS_BACKEND_SDL:
+        bbx_log(BBX_LOG_LEVEL_VERBOSE, "Using SDL2 backend");
+	disp = lv_sdl_window_create(config->hor_res > 0 ? config->hor_res: 800, config->ver_res > 0 ? config->ver_res: 480);
+        if (!disp) {
+            bbx_log(BBX_LOG_LEVEL_ERROR, "Failed to create SDL2 display");
+            return NULL;
+        }
+        break;
+#endif /* LV_USE_SDL */
+
     default:
         bbx_log(BBX_LOG_LEVEL_ERROR, "Unable to find suitable backend");
         return NULL;

unl0kr/lv_conf.h

@@ -1159,7 +1159,8 @@
  *==================*/
 
 /** Use SDL to open window on PC and handle mouse and keyboard. */
-#define LV_USE_SDL              0
+// LV_USE_SDL is defined dynamically via meson.build so we must not define it here
+// #define LV_USE_SDL              0
 #if LV_USE_SDL
     #define LV_SDL_INCLUDE_PATH     <SDL2/SDL.h>
     #define LV_SDL_RENDER_MODE      LV_DISPLAY_RENDER_MODE_DIRECT   /**< LV_DISPLAY_RENDER_MODE_DIRECT is recommended for best performance */
@@ -1231,6 +1232,7 @@
 #endif
 
 /** Driver for /dev/dri/card */
+// LV_USE_LINUX_DRM is defined dynamically via meson.build so we must not define it here
 //#define LV_USE_LINUX_DRM        0
 
 #if LV_USE_LINUX_DRM

unl0kr/meson.build

@@ -23,6 +23,13 @@ else
     unl0kr_args += '-DLV_USE_LINUX_DRM=0'
 endif
 
+if deplibsdl.found()
+    unl0kr_dependencies += deplibsdl
+    unl0kr_args += '-DLV_USE_SDL=1'
+else
+    unl0kr_args += '-DLV_USE_SDL=0'
+endif
+
 executable('unl0kr',
     include_directories: common_include_dirs,
     sources: unl0kr_sources + shared_sources + shared_sources_ul_f0 + squeek2lvgl_sources + lvgl_sources,