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.
19 #include <android/bitmap.h>
26 #define PI_F 3.141592653589f
30 ImageRGBA(unsigned char* image, int width, int height)
31 : image_(image), width_(width), height_(height) {
32 width_step_ = width * 4;
44 unsigned char* operator()(int x, int y) {
45 return image_ + y * width_step_ + x * 4;
47 const unsigned char* operator()(int x, int y) const {
48 return image_ + y * width_step_ + x * 4;
52 unsigned char* image_;
58 // Interpolate a pixel in a 3 channel image.
59 inline void InterpolatePixel(const ImageRGBA &image, float x, float y,
60 unsigned char* dest) {
61 // Get pointers and scale factors for the source pixels.
62 float ax = x - floor(x);
63 float ay = y - floor(y);
64 float axn = 1.0f - ax;
65 float ayn = 1.0f - ay;
66 const unsigned char *p = image(x, y);
67 const unsigned char *p2 = image(x, y + 1);
69 // Interpolate each image color plane.
70 dest[0] = static_cast<unsigned char>(axn * ayn * p[0] + ax * ayn * p[4] +
71 ax * ay * p2[4] + axn * ay * p2[0] + 0.5f);
75 dest[1] = static_cast<unsigned char>(axn * ayn * p[0] + ax * ayn * p[4] +
76 ax * ay * p2[4] + axn * ay * p2[0] + 0.5f);
80 dest[2] = static_cast<unsigned char>(axn * ayn * p[0] + ax * ayn * p[4] +
81 ax * ay * p2[4] + axn * ay * p2[0] + 0.5f);
87 // Wrap circular coordinates around the globe
88 inline float wrap(float value, float dimension) {
89 return value - (dimension * floor(value/dimension));
92 void StereographicProjection(float scale, float angle, unsigned char* input_image,
93 int input_width, int input_height,
94 unsigned char* output_image, int output_width,
96 ImageRGBA input(input_image, input_width, input_height);
97 ImageRGBA output(output_image, output_width, output_height);
99 const float image_scale = output_width * scale;
101 for (int x = 0; x < output_width; x++) {
102 // Center and scale x
103 float xf = (x - output_width / 2.0f) / image_scale;
105 for (int y = 0; y < output_height; y++) {
106 // Center and scale y
107 float yf = (y - output_height / 2.0f) / image_scale;
110 float r = hypotf(xf, yf);
111 float theta = angle+atan2(yf, xf);
112 if (theta>PI_F) theta-=2*PI_F;
114 // Project onto plane
115 float phi = 2 * atan(1 / r);
116 // (theta stays the same)
118 // Map to panorama image
119 float px = (theta / (2 * PI_F)) * input_width;
120 float py = (phi / PI_F) * input_height;
122 // Wrap around the globe
123 px = wrap(px, input_width);
124 py = wrap(py, input_height);
126 // Write the interpolated pixel
127 InterpolatePixel(input, px, py, output(x, y));
133 JNIEXPORT void JNICALL Java_com_android_camera_tinyplanet_TinyPlanetNative_process(JNIEnv* env,
134 jobject obj __unused, jobject bitmap_in, jint width, jint height, jobject bitmap_out,
135 jint output_size, jfloat scale, jfloat angle)
138 char* destination = 0;
139 AndroidBitmap_lockPixels(env, bitmap_in, (void**) &source);
140 AndroidBitmap_lockPixels(env, bitmap_out, (void**) &destination);
141 unsigned char * rgb_in = (unsigned char * )source;
142 unsigned char * rgb_out = (unsigned char * )destination;
144 StereographicProjection(scale, angle, rgb_in, width, height, rgb_out, output_size, output_size);
145 AndroidBitmap_unlockPixels(env, bitmap_in);
146 AndroidBitmap_unlockPixels(env, bitmap_out);