2 * Copyright (C) 2012 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
25 #define PI_F 3.141592653589f
29 ImageRGBA(unsigned char* image, int width, int height)
30 : image_(image), width_(width), height_(height) {
31 width_step_ = width * 4;
43 unsigned char* operator()(int x, int y) {
44 return image_ + y * width_step_ + x * 4;
46 const unsigned char* operator()(int x, int y) const {
47 return image_ + y * width_step_ + x * 4;
51 unsigned char* image_;
57 // Interpolate a pixel in a 3 channel image.
58 inline void InterpolatePixel(const ImageRGBA &image, float x, float y,
59 unsigned char* dest) {
60 // Get pointers and scale factors for the source pixels.
61 float ax = x - floor(x);
62 float ay = y - floor(y);
63 float axn = 1.0f - ax;
64 float ayn = 1.0f - ay;
65 const unsigned char *p = image(x, y);
66 const unsigned char *p2 = image(x, y + 1);
68 // Interpolate each image color plane.
69 dest[0] = static_cast<unsigned char>(axn * ayn * p[0] + ax * ayn * p[4] +
70 ax * ay * p2[4] + axn * ay * p2[0] + 0.5f);
74 dest[1] = static_cast<unsigned char>(axn * ayn * p[0] + ax * ayn * p[4] +
75 ax * ay * p2[4] + axn * ay * p2[0] + 0.5f);
79 dest[2] = static_cast<unsigned char>(axn * ayn * p[0] + ax * ayn * p[4] +
80 ax * ay * p2[4] + axn * ay * p2[0] + 0.5f);
85 // Wrap circular coordinates around the globe
86 inline float wrap(float value, float dimension) {
87 return value - (dimension * floor(value/dimension));
90 void StereographicProjection(float scale, unsigned char* input_image,
91 int input_width, int input_height,
92 unsigned char* output_image, int output_width,
94 ImageRGBA input(input_image, input_width, input_height);
95 ImageRGBA output(output_image, output_width, output_height);
97 const float image_scale = output_width * scale;
99 for (int x = 0; x < output_width; x++) {
100 // Center and scale x
101 float xf = (x - output_width / 2.0f) / image_scale;
103 for (int y = 0; y < output_height; y++) {
104 // Center and scale y
105 float yf = (y - output_height / 2.0f) / image_scale;
108 float r = hypotf(xf, yf);
109 float theta = atan2(yf, xf);
111 // Project onto plane
112 float phi = 2 * atan(1 / r);
113 // (theta stays the same)
115 // Map to panorama image
116 float px = (theta / (2 * PI_F)) * input_width;
117 float py = (phi / PI_F) * input_height;
119 // Wrap around the globe
120 px = wrap(px, input_width);
121 py = wrap(py, input_height);
123 // Write the interpolated pixel
124 InterpolatePixel(input, px, py, output(x, y));
130 void JNIFUNCF(ImageFilterTinyPlanet, nativeApplyFilter, jobject bitmap_in, jint width, jint height, jobject bitmap_out, jint output_size, jfloat scale)
133 char* destination = 0;
134 AndroidBitmap_lockPixels(env, bitmap_in, (void**) &source);
135 AndroidBitmap_lockPixels(env, bitmap_out, (void**) &destination);
136 unsigned char * rgb_in = (unsigned char * )source;
137 unsigned char * rgb_out = (unsigned char * )destination;
139 StereographicProjection(scale, rgb_in, width, height, rgb_out, output_size, output_size);
140 AndroidBitmap_unlockPixels(env, bitmap_in);
141 AndroidBitmap_unlockPixels(env, bitmap_out);