android: jpeg: Introduce a simple image thumbnailer

Add a basic image Thumbnailer class for the frames being captured.
Currently, the thumbnailer can scale NV12 frames. It shall be used
to generate a thumbnail image for EXIF metadata, in the subsequent
commit.

Signed-off-by: Umang Jain <email@uajain.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/src/android/jpeg/thumbnailer.h b/src/android/jpeg/thumbnailer.h
new file mode 100644
index 00000000..98f11833
--- /dev/null
+++ b/src/android/jpeg/thumbnailer.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * thumbnailer.h - Simple image thumbnailer
+ */
+#ifndef __ANDROID_JPEG_THUMBNAILER_H__
+#define __ANDROID_JPEG_THUMBNAILER_H__
+
+#include <libcamera/geometry.h>
+
+#include "libcamera/internal/buffer.h"
+#include "libcamera/internal/formats.h"
+
+class Thumbnailer
+{
+public:
+	Thumbnailer();
+
+	void configure(const libcamera::Size &sourceSize,
+		       libcamera::PixelFormat pixelFormat);
+	void createThumbnail(const libcamera::FrameBuffer &source,
+			     std::vector<unsigned char> *dest);
+	const libcamera::Size &size() const { return targetSize_; }
+
+private:
+	libcamera::Size computeThumbnailSize() const;
+
+	libcamera::PixelFormat pixelFormat_;
+	libcamera::Size sourceSize_;
+	libcamera::Size targetSize_;
+
+	bool valid_;
+};
+
+#endif /* __ANDROID_JPEG_THUMBNAILER_H__ */