separate fbdev-specific code out from minui
Isolate the code that interacts with fbdev, in preparation for adding
a new backend.
Change-Id: I19105e9da1ca6408cebc110f7e2bb5abfb481ee9
diff --git a/minui/graphics.h b/minui/graphics.h
new file mode 100644
index 0000000..94b89a5
--- /dev/null
+++ b/minui/graphics.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _GRAPHICS_H_
+#define _GRAPHICS_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdbool.h>
+#include "minui.h"
+
+typedef struct minui_backend {
+ // Initializes the backend and returns a gr_surface to draw into.
+ gr_surface (*init)(struct minui_backend*);
+
+ // Causes the current drawing surface (returned by the most recent
+ // call to flip() or init()) to be displayed, and returns a new
+ // drawing surface.
+ gr_surface (*flip)(struct minui_backend*);
+
+ // Blank (or unblank) the screen.
+ void (*blank)(struct minui_backend*, bool);
+
+ // Device cleanup when drawing is done.
+ void (*exit)(struct minui_backend*);
+} minui_backend;
+
+minui_backend* open_fbdev();
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif