libjpegrecoverymap: add JPEG encoder for single channel image

test: jpegencoder_test
bug: b/252835416
Change-Id: I6a13438ae4695569058645ad13c1182b7a626524
diff --git a/libs/jpegrecoverymap/include/jpegrecoverymap/jpegencoder.h b/libs/jpegrecoverymap/include/jpegrecoverymap/jpegencoder.h
index ec12918..9641fda 100644
--- a/libs/jpegrecoverymap/include/jpegrecoverymap/jpegencoder.h
+++ b/libs/jpegrecoverymap/include/jpegrecoverymap/jpegencoder.h
@@ -28,7 +28,8 @@
 namespace android::recoverymap {
 
 /*
- * Encapsulates a converter from YUV420Planer to JPEG format. This class is not thread-safe.
+ * Encapsulates a converter from raw image (YUV420planer or grey-scale) to JPEG format.
+ * This class is not thread-safe.
  */
 class JpegEncoder {
 public:
@@ -43,7 +44,7 @@
      * Returns false if errors occur during compression.
      */
     bool compressImage(const void* image, int width, int height, int quality,
-                       const void* iccBuffer, unsigned int iccSize);
+                       const void* iccBuffer, unsigned int iccSize, bool isSingleChannel = false);
 
     /*
      * Returns the compressed JPEG buffer pointer. This method must be called only after calling
@@ -67,11 +68,14 @@
 
     // Returns false if errors occur.
     bool encode(const void* inYuv, int width, int height, int jpegQuality,
-                const void* iccBuffer, unsigned int iccSize);
+                const void* iccBuffer, unsigned int iccSize, bool isSingleChannel);
     void setJpegDestination(jpeg_compress_struct* cinfo);
-    void setJpegCompressStruct(int width, int height, int quality, jpeg_compress_struct* cinfo);
+    void setJpegCompressStruct(int width, int height, int quality, jpeg_compress_struct* cinfo,
+                               bool isSingleChannel);
     // Returns false if errors occur.
-    bool compress(jpeg_compress_struct* cinfo, const uint8_t* yuv);
+    bool compress(jpeg_compress_struct* cinfo, const uint8_t* image, bool isSingleChannel);
+    bool compressYuv(jpeg_compress_struct* cinfo, const uint8_t* yuv);
+    bool compressSingleChannel(jpeg_compress_struct* cinfo, const uint8_t* image);
 
     // The block size for encoded jpeg image buffer.
     static const int kBlockSize = 16384;
diff --git a/libs/jpegrecoverymap/jpegencoder.cpp b/libs/jpegrecoverymap/jpegencoder.cpp
index b5d3a06..d45d9b3 100644
--- a/libs/jpegrecoverymap/jpegencoder.cpp
+++ b/libs/jpegrecoverymap/jpegencoder.cpp
@@ -36,14 +36,15 @@
 }
 
 bool JpegEncoder::compressImage(const void* image, int width, int height, int quality,
-                                   const void* iccBuffer, unsigned int iccSize) {
+                                   const void* iccBuffer, unsigned int iccSize,
+                                   bool isSingleChannel) {
     if (width % 8 != 0 || height % 2 != 0) {
         ALOGE("Image size can not be handled: %dx%d", width, height);
         return false;
     }
 
     mResultBuffer.clear();
-    if (!encode(image, width, height, quality, iccBuffer, iccSize)) {
+    if (!encode(image, width, height, quality, iccBuffer, iccSize, isSingleChannel)) {
         return false;
     }
     ALOGI("Compressed JPEG: %d[%dx%d] -> %zu bytes",
@@ -91,8 +92,8 @@
     ALOGE("%s\n", buffer);
 }
 
-bool JpegEncoder::encode(const void* inYuv, int width, int height, int jpegQuality,
-                           const void* iccBuffer, unsigned int iccSize) {
+bool JpegEncoder::encode(const void* image, int width, int height, int jpegQuality,
+                         const void* iccBuffer, unsigned int iccSize, bool isSingleChannel) {
     jpeg_compress_struct cinfo;
     jpeg_error_mgr jerr;
 
@@ -102,14 +103,14 @@
     jpeg_create_compress(&cinfo);
     setJpegDestination(&cinfo);
 
-    setJpegCompressStruct(width, height, jpegQuality, &cinfo);
+    setJpegCompressStruct(width, height, jpegQuality, &cinfo, isSingleChannel);
     jpeg_start_compress(&cinfo, TRUE);
 
     if (iccBuffer != nullptr && iccSize > 0) {
         jpeg_write_marker(&cinfo, JPEG_APP0 + 2, static_cast<const JOCTET*>(iccBuffer), iccSize);
     }
 
-    if (!compress(&cinfo, static_cast<const uint8_t*>(inYuv))) {
+    if (!compress(&cinfo, static_cast<const uint8_t*>(image), isSingleChannel)) {
         return false;
     }
     jpeg_finish_compress(&cinfo);
@@ -128,29 +129,44 @@
 }
 
 void JpegEncoder::setJpegCompressStruct(int width, int height, int quality,
-                                               jpeg_compress_struct* cinfo) {
+                                        jpeg_compress_struct* cinfo, bool isSingleChannel) {
     cinfo->image_width = width;
     cinfo->image_height = height;
-    cinfo->input_components = 3;
-    cinfo->in_color_space = JCS_YCbCr;
+    if (isSingleChannel) {
+        cinfo->input_components = 1;
+        cinfo->in_color_space = JCS_GRAYSCALE;
+    } else {
+        cinfo->input_components = 3;
+        cinfo->in_color_space = JCS_YCbCr;
+    }
     jpeg_set_defaults(cinfo);
 
     jpeg_set_quality(cinfo, quality, TRUE);
-    jpeg_set_colorspace(cinfo, JCS_YCbCr);
+    jpeg_set_colorspace(cinfo, isSingleChannel ? JCS_GRAYSCALE : JCS_YCbCr);
     cinfo->raw_data_in = TRUE;
     cinfo->dct_method = JDCT_IFAST;
 
-    // Configure sampling factors. The sampling factor is JPEG subsampling 420 because the
-    // source format is YUV420.
-    cinfo->comp_info[0].h_samp_factor = 2;
-    cinfo->comp_info[0].v_samp_factor = 2;
-    cinfo->comp_info[1].h_samp_factor = 1;
-    cinfo->comp_info[1].v_samp_factor = 1;
-    cinfo->comp_info[2].h_samp_factor = 1;
-    cinfo->comp_info[2].v_samp_factor = 1;
+    if (!isSingleChannel) {
+        // Configure sampling factors. The sampling factor is JPEG subsampling 420 because the
+        // source format is YUV420.
+        cinfo->comp_info[0].h_samp_factor = 2;
+        cinfo->comp_info[0].v_samp_factor = 2;
+        cinfo->comp_info[1].h_samp_factor = 1;
+        cinfo->comp_info[1].v_samp_factor = 1;
+        cinfo->comp_info[2].h_samp_factor = 1;
+        cinfo->comp_info[2].v_samp_factor = 1;
+    }
 }
 
-bool JpegEncoder::compress(jpeg_compress_struct* cinfo, const uint8_t* yuv) {
+bool JpegEncoder::compress(
+        jpeg_compress_struct* cinfo, const uint8_t* image, bool isSingleChannel) {
+    if (isSingleChannel) {
+        return compressSingleChannel(cinfo, image);
+    }
+    return compressYuv(cinfo, image);
+}
+
+bool JpegEncoder::compressYuv(jpeg_compress_struct* cinfo, const uint8_t* yuv) {
     JSAMPROW y[kCompressBatchSize];
     JSAMPROW cb[kCompressBatchSize / 2];
     JSAMPROW cr[kCompressBatchSize / 2];
@@ -194,4 +210,30 @@
     return true;
 }
 
+bool JpegEncoder::compressSingleChannel(jpeg_compress_struct* cinfo, const uint8_t* image) {
+    JSAMPROW y[kCompressBatchSize];
+    JSAMPARRAY planes[1] {y};
+
+    uint8_t* y_plane = const_cast<uint8_t*>(image);
+    std::unique_ptr<uint8_t[]> empty(new uint8_t[cinfo->image_width]);
+    memset(empty.get(), 0, cinfo->image_width);
+
+    while (cinfo->next_scanline < cinfo->image_height) {
+        for (int i = 0; i < kCompressBatchSize; ++i) {
+            size_t scanline = cinfo->next_scanline + i;
+            if (scanline < cinfo->image_height) {
+                y[i] = y_plane + scanline * cinfo->image_width;
+            } else {
+                y[i] = empty.get();
+            }
+        }
+        int processed = jpeg_write_raw_data(cinfo, planes, kCompressBatchSize);
+        if (processed != kCompressBatchSize / 2) {
+            ALOGE("Number of processed lines does not equal input lines.");
+            return false;
+        }
+    }
+    return true;
+}
+
 } // namespace android
\ No newline at end of file
diff --git a/libs/jpegrecoverymap/tests/data/minnie-320x240.y b/libs/jpegrecoverymap/tests/data/minnie-320x240.y
new file mode 100644
index 0000000..f9d8371
--- /dev/null
+++ b/libs/jpegrecoverymap/tests/data/minnie-320x240.y
Binary files differ
diff --git a/libs/jpegrecoverymap/tests/jpegencoder_test.cpp b/libs/jpegrecoverymap/tests/jpegencoder_test.cpp
index 2d144f0..4cd2a5e 100644
--- a/libs/jpegrecoverymap/tests/jpegencoder_test.cpp
+++ b/libs/jpegrecoverymap/tests/jpegencoder_test.cpp
@@ -25,6 +25,9 @@
 #define VALID_IMAGE "/sdcard/Documents/minnie-320x240.yu12"
 #define VALID_IMAGE_WIDTH 320
 #define VALID_IMAGE_HEIGHT 240
+#define SINGLE_CHANNEL_IMAGE "/sdcard/Documents/minnie-320x240.y"
+#define SINGLE_CHANNEL_IMAGE_WIDTH VALID_IMAGE_WIDTH
+#define SINGLE_CHANNEL_IMAGE_HEIGHT VALID_IMAGE_HEIGHT
 #define INVALID_SIZE_IMAGE "/sdcard/Documents/minnie-318x240.yu12"
 #define INVALID_SIZE_IMAGE_WIDTH 318
 #define INVALID_SIZE_IMAGE_HEIGHT 240
@@ -43,7 +46,7 @@
     virtual void SetUp();
     virtual void TearDown();
 
-    Image mValidImage, mInvalidSizeImage;
+    Image mValidImage, mInvalidSizeImage, mSingleChannelImage;
 };
 
 JpegEncoderTest::JpegEncoderTest() {}
@@ -89,6 +92,11 @@
     }
     mInvalidSizeImage.width = INVALID_SIZE_IMAGE_WIDTH;
     mInvalidSizeImage.height = INVALID_SIZE_IMAGE_HEIGHT;
+    if (!loadFile(SINGLE_CHANNEL_IMAGE, &mSingleChannelImage)) {
+        FAIL() << "Load file " << SINGLE_CHANNEL_IMAGE << " failed";
+    }
+    mSingleChannelImage.width = SINGLE_CHANNEL_IMAGE_WIDTH;
+    mSingleChannelImage.height = SINGLE_CHANNEL_IMAGE_HEIGHT;
 }
 
 void JpegEncoderTest::TearDown() {}
@@ -106,5 +114,12 @@
                                           mInvalidSizeImage.height, JPEG_QUALITY, NULL, 0));
 }
 
+TEST_F(JpegEncoderTest, singleChannelImage) {
+    JpegEncoder encoder;
+    EXPECT_TRUE(encoder.compressImage(mSingleChannelImage.buffer.get(), mSingleChannelImage.width,
+                                         mSingleChannelImage.height, JPEG_QUALITY, NULL, 0, true));
+    ASSERT_GT(encoder.getCompressedImageSize(), static_cast<uint32_t>(0));
+}
+
 }