2 * Copyright (c) 2011 Sveriges Television AB <info@casparcg.com>
4 * This file is part of CasparCG (www.casparcg.com).
6 * CasparCG is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * CasparCG is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with CasparCG. If not, see <http://www.gnu.org/licenses/>.
19 * Author: Helge Norberg, helge.norberg@svt.se
24 #include <common/tweener.h>
27 #include <boost/foreach.hpp>
29 namespace caspar { namespace image {
32 * Helper for calculating the color of a pixel given any number of of other
33 * pixels (each with their own weight).
41 : r(0), g(0), b(0), a(0), total_weight(0)
45 template<class RGBAPixel>
46 inline void add_pixel(const RGBAPixel& pixel, uint8_t weight)
48 r += pixel.r() * weight;
49 g += pixel.g() * weight;
50 b += pixel.b() * weight;
51 a += pixel.a() * weight;
53 total_weight += weight;
56 template<class RGBAPixel>
57 inline void store_result(RGBAPixel& pixel)
59 pixel.r() = static_cast<uint8_t>(r / total_weight);
60 pixel.g() = static_cast<uint8_t>(g / total_weight);
61 pixel.b() = static_cast<uint8_t>(b / total_weight);
62 pixel.a() = static_cast<uint8_t>(a / total_weight);
67 std::vector<T> get_tweened_values(const core::tweener& tweener, size_t num_values, T from, T to)
69 std::vector<T> result;
70 result.reserve(num_values);
72 double start = static_cast<double>(from);
73 double delta = static_cast<double>(to - from);
74 double duration = static_cast<double>(num_values);
76 for (double t = 0; t < duration; ++t)
78 result.push_back(static_cast<T>(tweener(t, start, delta, duration - 1.0)));
81 return std::move(result);
85 * Blur a source image and store the blurred result in a destination image.
87 * The blur is done by weighting each relative pixel from a destination pixel
88 * position using a vector of relative x-y pairs. The further away a related
89 * pixel is the less weight it gets. A tweener is used to calculate the actual
90 * weights of each related pixel.
92 * @param src The source view. Has to model the ImageView
93 * concept and have a pixel type modelling the
95 * @param dst The destination view. Has to model the
96 * ImageView concept and have a pixel type
97 * modelling the RGBAPixel concept.
98 * @param motion_trail_coordinates The relative x-y positions to weight in for
100 * @param tweener The tweener to use for calculating the
101 * weights of each relative position in the
104 template<class SrcView, class DstView>
108 const std::vector<std::pair<int, int>> motion_trail_coordinates,
109 const core::tweener& tweener)
111 auto blur_px = motion_trail_coordinates.size();
112 auto tweened_weights_y = get_tweened_values<uint8_t>(tweener, blur_px + 2, 255, 0);
113 tweened_weights_y.pop_back();
114 tweened_weights_y.erase(tweened_weights_y.begin());
116 auto src_end = src.end();
117 auto dst_iter = dst.begin();
119 for (auto src_iter = src.begin(); src_iter != src_end; ++src_iter, ++dst_iter)
123 for (int i = 0; i < blur_px; ++i)
125 auto& coordinate = motion_trail_coordinates[i];
126 auto other_pixel = src.relative(src_iter, coordinate.first, coordinate.second);
128 if (other_pixel == nullptr)
131 w.add_pixel(*other_pixel, tweened_weights_y[i]);
134 w.add_pixel(*src_iter, 255);
135 w.store_result(*dst_iter);
140 * Calculate relative x-y coordinates of a straight line with a given angle and
141 * a given number of points.
143 * @param num_pixels The number of pixels/points to create.
144 * @param angle_radians The angle of the line in radians.
146 * @return the x-y pairs.
148 std::vector<std::pair<int, int>> get_line_points(int num_pixels, double angle_radians)
150 std::vector<std::pair<int, int>> line_points;
151 line_points.reserve(num_pixels);
153 double delta_x = std::cos(angle_radians);
154 double delta_y = -std::sin(angle_radians); // In memory is revered
155 double max_delta = std::max(std::abs(delta_x), std::abs(delta_y));
156 double amplification = 1.0 / max_delta;
157 delta_x *= amplification;
158 delta_y *= amplification;
160 for (int i = 1; i <= num_pixels; ++i)
161 line_points.push_back(std::make_pair(
162 static_cast<int>(std::floor(delta_x * static_cast<double>(i) + 0.5)),
163 static_cast<int>(std::floor(delta_y * static_cast<double>(i) + 0.5))));
165 return std::move(line_points);
169 * Directionally blur a source image modelling the ImageView concept and store
170 * the blurred image to a destination image also modelling the ImageView
173 * The pixel type of the views must model the RGBAPixel concept.
175 * @param src The source image view. Has to model the ImageView
176 * concept and have a pixel type that models RGBAPixel.
177 * @param dst The destiation image view. Has to model the ImageView
178 * concept and have a pixel type that models RGBAPixel.
179 * @param angle_radians The angle in radians to directionally blur the image.
180 * @param blur_px The number of pixels of the blur.
181 * @param tweener The tweener to use to create a pixel weighting curve
184 template<class SrcView, class DstView>
188 double angle_radians,
190 const core::tweener& tweener)
192 auto motion_trail = get_line_points(blur_px, angle_radians);
194 blur(src, dst, motion_trail, tweener);
198 * Premultiply with alpha for each pixel in an ImageView. The modifications is
199 * done in place. The pixel type of the ImageView must model the RGBAPixel
202 * @param view_to_modify The image view to premultiply in place. Has to model
203 * the ImageView concept and have a pixel type that
206 template<class SrcDstView>
207 void premultiply(SrcDstView& view_to_modify)
209 std::for_each(view_to_modify.begin(), view_to_modify.end(), [&](SrcDstView::pixel_type& pixel)
211 int alpha = static_cast<int>(pixel.a());
213 if (alpha != 255) // Performance optimization
215 // We don't event try to premultiply 0 since it will be unaffected.
217 pixel.r() = static_cast<uint8_t>(static_cast<int>(pixel.r()) * alpha / 255);
220 pixel.g() = static_cast<uint8_t>(static_cast<int>(pixel.g()) * alpha / 255);
223 pixel.b() = static_cast<uint8_t>(static_cast<int>(pixel.b()) * alpha / 255);