convolution.cpp revision 0f8a40e4cfdc5f6cd47c22e81f69ed0446067c54 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <android/bitmap.h>
18
19#include <cstdlib>
20
21#include "utils.h"
22
23using android::apps::photoeditor::utils::clamp;
24using android::apps::photoeditor::utils::LockBitmaps;
25using android::apps::photoeditor::utils::pixel32_t;
26using android::apps::photoeditor::utils::UnlockBitmaps;
27
28namespace android {
29namespace apps {
30namespace photoeditor {
31namespace convolution {
32
33/*
34 * Used for convolution of following kernel:
35 *   n n n
36 *   n c n
37 *   n n n
38 * n: neighbor, c: center
39 */
40void SpecialConvolution(AndroidBitmapInfo *src_info, AndroidBitmapInfo *dst_info,
41    void *src_pixels, void *dst_pixels, float neighbor) {
42
43  if (neighbor == 0) {
44    memcpy(dst_pixels, src_pixels, src_info->stride * src_info->height);
45    return;
46  }
47
48  /* Copy the first row to dst_pixels */
49  memcpy(dst_pixels, src_pixels, src_info->stride);
50  src_pixels = reinterpret_cast<char*>(src_pixels) + src_info->stride;
51  dst_pixels = reinterpret_cast<char*>(dst_pixels) + dst_info->stride;
52
53  const int32_t kShiftBits = 10;
54  int32_t fixed_neighbor = static_cast<int32_t>((1 << kShiftBits) * neighbor);
55  int32_t fixed_center = static_cast<int32_t>((1 << kShiftBits) * (1 - neighbor * 8));
56
57  for (uint32_t scan_line = 1; scan_line < dst_info->height - 1; scan_line++) {
58    pixel32_t* src = reinterpret_cast<pixel32_t*>(src_pixels);
59    uint32_t* src_prev = reinterpret_cast<uint32_t*>
60        (reinterpret_cast<char*>(src_pixels) - src_info->stride);
61    uint32_t* src_next = reinterpret_cast<uint32_t*>
62        (reinterpret_cast<char*>(src_pixels) + src_info->stride);
63
64    uint32_t* dst = reinterpret_cast<uint32_t*>(dst_pixels);
65    *dst++ = src->rgba32;
66    src++;
67    src_prev++;
68    src_next++;
69
70    uint32_t* dst_line_end = dst + dst_info->width - 1;
71    while (dst < dst_line_end) {
72      int32_t src_red = src->rgba8[0];
73      int32_t src_green = src->rgba8[1];
74      int32_t src_blue = src->rgba8[2];
75      int32_t src_alpha = src->rgba8[3];
76
77      uint8_t* n1 = reinterpret_cast<uint8_t*>(src_prev - 1);
78      uint8_t* n2 = reinterpret_cast<uint8_t*>(src - 1);
79      uint8_t* n3 = reinterpret_cast<uint8_t*>(src_next - 1);
80      uint8_t* n4 = reinterpret_cast<uint8_t*>(src_prev);
81      uint8_t* n5 = reinterpret_cast<uint8_t*>(src_next);
82      uint8_t* n6 = reinterpret_cast<uint8_t*>(src_prev + 1);
83      uint8_t* n7 = reinterpret_cast<uint8_t*>(src + 1);
84      uint8_t* n8 = reinterpret_cast<uint8_t*>(src_next + 1);
85
86      int32_t red = n1[0] + n2[0] + n3[0] + n4[0] + n5[0] + n6[0] + n7[0] + n8[0];
87      int32_t green = n1[1] + n2[1] + n3[1] + n4[1] + n5[1] + n6[1] + n7[1] + n8[1];
88      int32_t blue = n1[2] + n2[2] + n3[2] + n4[2] + n5[2] + n6[2] + n7[2] + n8[2];
89
90      red = (fixed_neighbor * red + fixed_center * src_red) >> kShiftBits;
91      green = (fixed_neighbor * green + fixed_center * src_green) >> kShiftBits;
92      blue = (fixed_neighbor * blue + fixed_center * src_blue) >> kShiftBits;
93
94      red = clamp(red, 0, 255);
95      green = clamp(green, 0, 255);
96      blue = clamp(blue, 0, 255);
97
98      *dst = (src_alpha << 24) | (blue << 16) | (green << 8) | red;
99      dst++;
100      src++;
101      src_prev++;
102      src_next++;
103    }
104    *dst = src->rgba32;
105    src_pixels = reinterpret_cast<char*>(src_pixels) + src_info->stride;
106    dst_pixels = reinterpret_cast<char*>(dst_pixels) + dst_info->stride;
107  }
108
109  /* Copy the last row to dst_pixels */
110  memcpy(dst_pixels, src_pixels, src_info->stride);
111}
112
113}  // namespace convolution
114}  // namespace photoeditor
115}  // namespace apps
116}  // namespace android
117