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>
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).
43 template<class RGBAPixel>
44 inline void add_pixel(const RGBAPixel& pixel, uint8_t weight)
46 r += pixel.r() * weight;
47 g += pixel.g() * weight;
48 b += pixel.b() * weight;
49 a += pixel.a() * weight;
51 total_weight += weight;
54 template<class RGBAPixel>
55 inline void store_result(RGBAPixel& pixel)
57 pixel.r() = static_cast<uint8_t>(r / total_weight);
58 pixel.g() = static_cast<uint8_t>(g / total_weight);
59 pixel.b() = static_cast<uint8_t>(b / total_weight);
60 pixel.a() = static_cast<uint8_t>(a / total_weight);
65 std::vector<T> get_tweened_values(const core::tweener& tweener, size_t num_values, T from, T to)
67 std::vector<T> result;
68 result.reserve(num_values);
70 double start = static_cast<double>(from);
71 double delta = static_cast<double>(to - from);
72 double duration = static_cast<double>(num_values);
74 for (double t = 0; t < duration; ++t)
76 result.push_back(static_cast<T>(tweener(t, start, delta, duration - 1.0)));
79 return std::move(result);
83 * Blur a source image and store the blurred result in a destination image.
85 * The blur is done by weighting each relative pixel from a destination pixel
86 * position using a vector of relative x-y pairs. The further away a related
87 * pixel is the less weight it gets. A tweener is used to calculate the actual
88 * weights of each related pixel.
90 * @param src The source view. Has to model the ImageView
91 * concept and have a pixel type modelling the
93 * @param dst The destination view. Has to model the
94 * ImageView concept and have a pixel type
95 * modelling the RGBAPixel concept.
96 * @param motion_trail_coordinates The relative x-y positions to weight in for
98 * @param tweener The tweener to use for calculating the
99 * weights of each relative position in the
102 template<class SrcView, class DstView>
106 const std::vector<std::pair<int, int>>& motion_trail_coordinates,
107 const core::tweener& tweener)
109 auto blur_px = motion_trail_coordinates.size();
110 auto tweened_weights_y = get_tweened_values<uint8_t>(tweener, blur_px + 2, 255, 0);
111 tweened_weights_y.pop_back();
112 tweened_weights_y.erase(tweened_weights_y.begin());
114 auto src_end = src.end();
115 auto dst_iter = dst.begin();
117 for (auto src_iter = src.begin(); src_iter != src_end; ++src_iter, ++dst_iter)
121 for (int i = 0; i < blur_px; ++i)
123 auto& coordinate = motion_trail_coordinates[i];
124 auto other_pixel = src.relative(src_iter, coordinate.first, coordinate.second);
126 if (other_pixel == nullptr)
129 w.add_pixel(*other_pixel, tweened_weights_y[i]);
132 w.add_pixel(*src_iter, 255);
133 w.store_result(*dst_iter);
138 * Calculate relative x-y coordinates of a straight line with a given angle and
139 * a given number of points.
141 * @param num_pixels The number of pixels/points to create.
142 * @param angle_radians The angle of the line in radians.
144 * @return the x-y pairs.
146 std::vector<std::pair<int, int>> get_line_points(int num_pixels, double angle_radians);
149 * Directionally blur a source image modelling the ImageView concept and store
150 * the blurred image to a destination image also modelling the ImageView
153 * The pixel type of the views must model the RGBAPixel concept.
155 * @param src The source image view. Has to model the ImageView
156 * concept and have a pixel type that models RGBAPixel.
157 * @param dst The destiation image view. Has to model the ImageView
158 * concept and have a pixel type that models RGBAPixel.
159 * @param angle_radians The angle in radians to directionally blur the image.
160 * @param blur_px The number of pixels of the blur.
161 * @param tweener The tweener to use to create a pixel weighting curve
164 template<class SrcView, class DstView>
168 double angle_radians,
170 const core::tweener& tweener)
172 auto motion_trail = get_line_points(blur_px, angle_radians);
174 blur(src, dst, motion_trail, tweener);
178 * Premultiply with alpha for each pixel in an ImageView. The modifications is
179 * done in place. The pixel type of the ImageView must model the RGBAPixel
182 * @param view_to_modify The image view to premultiply in place. Has to model
183 * the ImageView concept and have a pixel type that
186 template<class SrcDstView>
187 void premultiply(SrcDstView& view_to_modify)
189 std::for_each(view_to_modify.begin(), view_to_modify.end(), [&](SrcDstView::pixel_type& pixel)
191 int alpha = static_cast<int>(pixel.a());
193 if (alpha != 255) // Performance optimization
195 // We don't event try to premultiply 0 since it will be unaffected.
197 pixel.r() = static_cast<uint8_t>(static_cast<int>(pixel.r()) * alpha / 255);
200 pixel.g() = static_cast<uint8_t>(static_cast<int>(pixel.g()) * alpha / 255);
203 pixel.b() = static_cast<uint8_t>(static_cast<int>(pixel.b()) * alpha / 255);