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