# mapnik/mapnik

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 /***************************************************************************** * * This file is part of Mapnik (c++ mapping toolkit) * * Copyright (C) 2011 Artem Pavlenko * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * *****************************************************************************/ #include #include namespace mapnik { rgb::rgb(rgba const& c) : r(c.r), g(c.g), b(c.b) {} // ordering by mean(a,r,g,b), a, r, g, b bool rgba::mean_sort_cmp::operator() (const rgba& x, const rgba& y) const { int t1 = (int)x.a + x.r + x.g + x.b; int t2 = (int)y.a + y.r + y.g + y.b; if (t1 != t2) return t1 < t2; // https://github.com/mapnik/mapnik/issues/1087 if (x.a != y.a) return x.a < y.a; if (x.r != y.r) return x.r < y.r; if (x.g != y.g) return x.g < y.g; return x.b < y.b; } std::size_t rgba::hash_func::operator()(rgba const& p) const { return ((std::size_t)p.r * 33023 + (std::size_t)p.g * 30013 + (std::size_t)p.b * 27011 + (std::size_t)p.a * 24007) % 21001; } rgba_palette::rgba_palette(std::string const& pal, palette_type type) : colors_(0) { parse(pal, type); } rgba_palette::rgba_palette() : colors_(0) {} const std::vector& rgba_palette::palette() const { return rgb_pal_; } const std::vector& rgba_palette::alphaTable() const { return alpha_pal_; } bool rgba_palette::valid() const { return colors_ > 0; } // return color index in returned earlier palette unsigned rgba_palette::quantize(rgba const& c) const { unsigned index = 0; if (colors_ == 1) return index; rgba_hash_table::iterator it = color_hashmap_.find(c); if (it != color_hashmap_.end()) { index = it->second; } else { int dr, dg, db, da; int dist, newdist; // find closest match based on mean of r,g,b,a std::vector::const_iterator pit = std::lower_bound(sorted_pal_.begin(), sorted_pal_.end(), c, rgba::mean_sort_cmp()); index = pit - sorted_pal_.begin(); if (index == sorted_pal_.size()) index--; dr = sorted_pal_[index].r - c.r; dg = sorted_pal_[index].g - c.g; db = sorted_pal_[index].b - c.b; da = sorted_pal_[index].a - c.a; dist = dr*dr + dg*dg + db*db + da*da; int poz = index; // search neighbour positions in both directions for better match for (int i = poz - 1; i >= 0; i--) { dr = sorted_pal_[i].r - c.r; dg = sorted_pal_[i].g - c.g; db = sorted_pal_[i].b - c.b; da = sorted_pal_[i].a - c.a; // stop criteria based on properties of used sorting if ((dr+db+dg+da) * (dr+db+dg+da) / 4 > dist) { break; } newdist = dr*dr + dg*dg + db*db + da*da; if (newdist < dist) { index = i; dist = newdist; } } for (unsigned i = poz + 1; i < sorted_pal_.size(); i++) { dr = sorted_pal_[i].r - c.r; dg = sorted_pal_[i].g - c.g; db = sorted_pal_[i].b - c.b; da = sorted_pal_[i].a - c.a; // stop criteria based on properties of used sorting if ((dr+db+dg+da) * (dr+db+dg+da) / 4 > dist) { break; } newdist = dr*dr + dg*dg + db*db + da*da; if (newdist < dist) { index = i; dist = newdist; } } // Cache found index for the color c into the hashmap. color_hashmap_[c] = index; } return index; } void rgba_palette::parse(std::string const& pal, palette_type type) { unsigned length = pal.length(); if ((type == PALETTE_RGBA && length % 4 > 0) || (type == PALETTE_RGB && length % 3 > 0) || (type == PALETTE_ACT && length != 772)) { throw config_error("invalid palette length"); } if (type == PALETTE_ACT) { length = (pal[768] << 8 | pal[769]) * 3; } sorted_pal_.clear(); color_hashmap_.clear(); rgb_pal_.clear(); alpha_pal_.clear(); if (type == PALETTE_RGBA) { for (unsigned i = 0; i < length; i += 4) { sorted_pal_.push_back(rgba(pal[i], pal[i + 1], pal[i + 2], pal[i + 3])); } } else { for (unsigned i = 0; i < length; i += 3) { sorted_pal_.push_back(rgba(pal[i], pal[i + 1], pal[i + 2], 0xFF)); } } // Make sure we have at least one entry in the palette. if (sorted_pal_.size() == 0) { sorted_pal_.push_back(rgba(0, 0, 0, 0)); } colors_ = sorted_pal_.size(); // Sort palette for binary searching in quantization std::sort(sorted_pal_.begin(), sorted_pal_.end(), rgba::mean_sort_cmp()); // Insert all palette colors into the hashmap and into the palette vectors. for (unsigned i = 0; i < colors_; i++) { rgba c = sorted_pal_[i]; color_hashmap_[c] = i; rgb_pal_.push_back(rgb(c)); if (c.a < 0xFF) { alpha_pal_.push_back(c.a); } } } } // namespace mapnik