diff options
| -rw-r--r-- | src/android/jpeg/thumbnailer.cpp | 112 | ||||
| -rw-r--r-- | src/android/jpeg/thumbnailer.h | 36 | ||||
| -rw-r--r-- | src/android/meson.build | 1 |
3 files changed, 149 insertions, 0 deletions
diff --git a/src/android/jpeg/thumbnailer.cpp b/src/android/jpeg/thumbnailer.cpp new file mode 100644 index 00000000..5374538a --- /dev/null +++ b/src/android/jpeg/thumbnailer.cpp @@ -0,0 +1,112 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2020, Google Inc. + * + * thumbnailer.cpp - Simple image thumbnailer + */ + +#include "thumbnailer.h" + +#include <libcamera/formats.h> + +#include "libcamera/internal/log.h" + +using namespace libcamera; + +LOG_DEFINE_CATEGORY(Thumbnailer) + +Thumbnailer::Thumbnailer() + : valid_(false) +{ +} + +void Thumbnailer::configure(const Size &sourceSize, PixelFormat pixelFormat) +{ + sourceSize_ = sourceSize; + pixelFormat_ = pixelFormat; + + if (pixelFormat_ != formats::NV12) { + LOG(Thumbnailer, Error) + << "Failed to configure: Pixel Format " + << pixelFormat_.toString() << " unsupported."; + return; + } + + targetSize_ = computeThumbnailSize(); + + valid_ = true; +} + +/* + * The Exif specification recommends the width of the thumbnail to be a + * multiple of 16 (section 4.8.1). Hence, compute the corresponding height + * keeping the aspect ratio same as of the source. + */ +Size Thumbnailer::computeThumbnailSize() const +{ + unsigned int targetHeight; + constexpr unsigned int kTargetWidth = 160; + + targetHeight = kTargetWidth * sourceSize_.height / sourceSize_.width; + + if (targetHeight & 1) + targetHeight++; + + return Size(kTargetWidth, targetHeight); +} + +void Thumbnailer::createThumbnail(const FrameBuffer &source, + std::vector<unsigned char> *destination) +{ + MappedFrameBuffer frame(&source, PROT_READ); + if (!frame.isValid()) { + LOG(Thumbnailer, Error) + << "Failed to map FrameBuffer : " + << strerror(frame.error()); + return; + } + + if (!valid_) { + LOG(Thumbnailer, Error) << "Config is unconfigured or invalid."; + return; + } + + const unsigned int sw = sourceSize_.width; + const unsigned int sh = sourceSize_.height; + const unsigned int tw = targetSize_.width; + const unsigned int th = targetSize_.height; + + ASSERT(tw % 2 == 0 && th % 2 == 0); + + /* Image scaling block implementing nearest-neighbour algorithm. */ + unsigned char *src = static_cast<unsigned char *>(frame.maps()[0].data()); + unsigned char *srcC = src + sh * sw; + unsigned char *srcCb, *srcCr; + unsigned char *dstY, *srcY; + + size_t dstSize = (th * tw) + ((th / 2) * tw); + destination->resize(dstSize); + unsigned char *dst = destination->data(); + unsigned char *dstC = dst + th * tw; + + for (unsigned int y = 0; y < th; y += 2) { + unsigned int sourceY = (sh * y + th / 2) / th; + + dstY = dst + y * tw; + srcY = src + sw * sourceY; + srcCb = srcC + (sourceY / 2) * sw + 0; + srcCr = srcC + (sourceY / 2) * sw + 1; + + for (unsigned int x = 0; x < tw; x += 2) { + unsigned int sourceX = (sw * x + tw / 2) / tw; + + dstY[x] = srcY[sourceX]; + dstY[tw + x] = srcY[sw + sourceX]; + dstY[x + 1] = srcY[sourceX + 1]; + dstY[tw + x + 1] = srcY[sw + sourceX + 1]; + + dstC[(y / 2) * tw + x + 0] = srcCb[(sourceX / 2) * 2]; + dstC[(y / 2) * tw + x + 1] = srcCr[(sourceX / 2) * 2]; + } + } +} 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__ */ diff --git a/src/android/meson.build b/src/android/meson.build index f72376a0..3d4d3be4 100644 --- a/src/android/meson.build +++ b/src/android/meson.build @@ -25,6 +25,7 @@ android_hal_sources = files([ 'jpeg/encoder_libjpeg.cpp', 'jpeg/exif.cpp', 'jpeg/post_processor_jpeg.cpp', + 'jpeg/thumbnailer.cpp', ]) android_camera_metadata_sources = files([ |