| /* |
| * Copyright (C) 2012 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. |
| */ |
| |
| // Native function to extract histogram from image (handed down as ByteBuffer). |
| |
| #include "sobeloperator.h" |
| |
| #include <math.h> |
| #include <string.h> |
| #include <jni.h> |
| #include <unistd.h> |
| #include <android/log.h> |
| |
| #include "imgprocutil.h" |
| |
| /* |
| * Perform 1d convolution on 3 channel image either horizontally or vertically. |
| * Parameters: |
| * inputHead: pointer to input image |
| * length: the length of image in the chosen axis. |
| * fragments: number of lines of the image in the chosen axis. |
| * step: the 1d pixel distance between adjacent pixels in the chosen axis. |
| * shift: the 1d pixel distance between adjacent lines in the chosen axis. |
| * filter: pointer to 1d filter |
| * halfSize: the length of filter is supposed to be (2 * halfSize + 1) |
| * outputHead: pointer to output image |
| */ |
| |
| void computeGradient(unsigned char* dataPtr, int width, int height, short* gxPtr, short* gyPtr) { |
| for (int i = 0; i < height; i++) { |
| for (int j = 0; j < width; j++) { |
| const int left = (j > 0)? -4 : 0; |
| const int right = (j < width - 1) ? 4 : 0; |
| const int curr = (i * width + j) * 4; |
| const int above = (i > 0) ? curr - 4 * width : curr; |
| const int below = (i < height - 1) ? curr + 4 * width : curr; |
| const int offset = (i * width + j) * 3; |
| for (int c = 0; c < 3; c++) { |
| *(gxPtr + offset + c) = |
| (*(dataPtr + curr + c + right) - *(dataPtr + curr + c + left)) * 2 + |
| *(dataPtr + above + c + right) - *(dataPtr + above + c + left) + |
| *(dataPtr + below + c + right) - *(dataPtr + below + c + left); |
| *(gyPtr + offset + c) = |
| (*(dataPtr + c + below) - *(dataPtr + c + above)) * 2 + |
| *(dataPtr + left + c + below) - *(dataPtr + left + c + above) + |
| *(dataPtr + right + c + below) - *(dataPtr + right + c + above); |
| } |
| } |
| } |
| } |
| |
| jboolean Java_androidx_media_filterpacks_image_SobelFilter_sobelOperator( |
| JNIEnv* env, jclass clazz, jint width, jint height, jobject imageBuffer, |
| jobject magBuffer, jobject dirBuffer) { |
| |
| if (imageBuffer == 0) { |
| return JNI_FALSE; |
| } |
| unsigned char* srcPtr = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer)); |
| unsigned char* magPtr = (magBuffer == 0) ? |
| 0 : static_cast<unsigned char*>(env->GetDirectBufferAddress(magBuffer)); |
| unsigned char* dirPtr = (dirBuffer == 0) ? |
| 0 : static_cast<unsigned char*>(env->GetDirectBufferAddress(dirBuffer)); |
| |
| int numPixels = width * height; |
| // TODO: avoid creating and deleting these buffers within this native function. |
| short* gxPtr = new short[3 * numPixels]; |
| short* gyPtr = new short[3 * numPixels]; |
| computeGradient(srcPtr, width, height, gxPtr, gyPtr); |
| |
| unsigned char* mag = magPtr; |
| unsigned char* dir = dirPtr; |
| for (int i = 0; i < numPixels; ++i) { |
| for (int c = 0; c < 3; c++) { |
| int gx = static_cast<int>(*(gxPtr + 3 * i + c) / 8 + 127.5); |
| int gy = static_cast<int>(*(gyPtr + 3 * i + c) / 8 + 127.5); |
| |
| // emulate arithmetic in GPU. |
| gx = 2 * gx - 255; |
| gy = 2 * gy - 255; |
| if (magPtr != 0) { |
| double value = sqrt(gx * gx + gy * gy); |
| *(magPtr + 4 * i + c) = static_cast<unsigned char>(value); |
| } |
| if (dirPtr != 0) { |
| *(dirPtr + 4 * i + c) = static_cast<unsigned char>( |
| (atan(static_cast<double>(gy)/static_cast<double>(gx)) + 3.14) / 6.28); |
| } |
| } |
| //setting alpha change to 1.0 (255) |
| if (magPtr != 0) { |
| *(magPtr + 4 * i + 3) = 255; |
| } |
| if (dirPtr != 0) { |
| *(dirPtr + 4 * i + 3) = 255; |
| } |
| } |
| |
| delete[] gxPtr; |
| delete[] gyPtr; |
| |
| return JNI_TRUE; |
| } |