| /* |
| * Copyright (C) 2016 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. |
| */ |
| |
| #include "Thumbnail.h" |
| |
| #define LOG_NDEBUG 0 |
| #define LOG_TAG "EmulatedCamera_Thumbnail" |
| #include <log/log.h> |
| #include <libexif/exif-data.h> |
| #include <libyuv.h> |
| |
| #include "JpegCompressor.h" |
| |
| #include <vector> |
| |
| /* |
| * The YU12 format is a YUV format with an 8-bit Y-component and the U and V |
| * components are stored as 8 bits each but they are shared between a block of |
| * 2x2 pixels. So when calculating bits per pixel the 16 bits of U and V are |
| * shared between 4 pixels leading to 4 bits of U and V per pixel. Together |
| * with the 8 bits of Y this gives us 12 bits per pixel.. |
| * |
| * The components are not grouped by pixels but separated into one Y-plane, one |
| * U-plane and one V-plane. |
| */ |
| |
| namespace android { |
| |
| static bool createRawThumbnail(const unsigned char* sourceImage, |
| int sourceWidth, int sourceHeight, |
| int thumbnailWidth, int thumbnailHeight, |
| std::vector<unsigned char>* thumbnail) { |
| const unsigned char* ySourcePlane = sourceImage; |
| const unsigned char* uSourcePlane = sourceImage + sourceWidth * sourceHeight; |
| const unsigned char* vSourcePlane = uSourcePlane + sourceWidth * sourceHeight / 4; |
| |
| // Create enough space in the output vector for the result |
| thumbnail->resize((thumbnailWidth * thumbnailHeight * 12) / 8); |
| |
| // The downscaled U and V planes will also be linear instead of interleaved, |
| // allocate space for them here |
| const size_t destUVPlaneSize = (thumbnailWidth * thumbnailHeight) / 4; |
| std::vector<unsigned char> destPlanes(destUVPlaneSize * 2); |
| unsigned char* yDestPlane = &(*thumbnail)[0]; |
| unsigned char* uDestPlane = yDestPlane + thumbnailWidth * thumbnailHeight; |
| unsigned char* vDestPlane = uDestPlane + thumbnailWidth * thumbnailHeight / 4; |
| |
| // The strides for the U and V planes are half the width because the U and V |
| // components are common to 2x2 pixel blocks |
| int result = libyuv::I420Scale(ySourcePlane, sourceWidth, |
| uSourcePlane, sourceWidth / 2, |
| vSourcePlane, sourceWidth / 2, |
| sourceWidth, sourceHeight, |
| yDestPlane, thumbnailWidth, |
| uDestPlane, thumbnailWidth / 2, |
| vDestPlane, thumbnailWidth / 2, |
| thumbnailWidth, thumbnailHeight, |
| libyuv::kFilterBilinear); |
| if (result != 0) { |
| ALOGE("Unable to create thumbnail, downscaling failed with error: %d", |
| result); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool createThumbnail(const unsigned char* sourceImage, |
| int sourceWidth, int sourceHeight, |
| int thumbWidth, int thumbHeight, int quality, |
| ExifData* exifData) { |
| if (thumbWidth <= 0 || thumbHeight <= 0) { |
| ALOGE("%s: Invalid thumbnail width=%d or height=%d, must be > 0", |
| __FUNCTION__, thumbWidth, thumbHeight); |
| return false; |
| } |
| |
| // First downscale the source image into a thumbnail-sized raw image |
| std::vector<unsigned char> rawThumbnail; |
| if (!createRawThumbnail(sourceImage, sourceWidth, sourceHeight, |
| thumbWidth, thumbHeight, &rawThumbnail)) { |
| // The thumbnail function will log an appropriate error if needed |
| return false; |
| } |
| |
| // And then compress it into JPEG format without any EXIF data |
| NV21JpegCompressor compressor; |
| status_t result = compressor.compressRawImage(&rawThumbnail[0], |
| thumbWidth, thumbHeight, |
| quality, nullptr /* EXIF */); |
| if (result != NO_ERROR) { |
| ALOGE("%s: Unable to compress thumbnail", __FUNCTION__); |
| return false; |
| } |
| |
| // And finally put it in the EXIF data. This transfers ownership of the |
| // malloc'd memory to the EXIF data structure. As long as the EXIF data |
| // structure is free'd using the EXIF library this memory will be free'd. |
| exifData->size = compressor.getCompressedSize(); |
| exifData->data = reinterpret_cast<unsigned char*>(malloc(exifData->size)); |
| if (exifData->data == nullptr) { |
| ALOGE("%s: Unable to allocate %u bytes of memory for thumbnail", |
| __FUNCTION__, exifData->size); |
| exifData->size = 0; |
| return false; |
| } |
| compressor.getCompressedImage(exifData->data); |
| return true; |
| } |
| |
| } // namespace android |
| |