source: spip-zone/_plugins_/filtres_images_vectorise/trunk/filtres/image_potrace.php @ 116199

<?php
/**
 * Generation d'une preview svg
 *
 * @plugin     Adaptive Images
 * @copyright  2013-2019
 * @author     Cedric
 * @licence    GNU/GPL
 * @package    SPIP\Adaptive_Images\Preview
 */

use Potracio\Potracio;

/**
 * Generation d'une Image SVG a partir d'un bitmap
 * en utilisant Potracio PHP qui est un portage PHP de PotRace
 * https://seenthis.net/messages/645575
 *
 * @param string $img
 * @param array $options
 * @return string
 */
function image_potrace($img, $options=[]) {

        include_spip("inc/filtres_images_lib_mini");
        include_spip('lib/potracio/Potracio');
        include_spip('filtres/couleurs');

        // dimension de la miniature a vectoriser
        $width_thumb = 512;
        if (isset($options['width_thumb'])) {
                $width_thumb = $options['width_thumb'];
                unset($options['width_thumb']);
        }
        $potconfig = [
                'turnpolicy' => "minority", // "black" / "white" / "left" / "right" / "minority" / "majority"
                'turdsize' => 2,
                'optcurve' => true,
                'alphamax' => 0.75,
                'opttolerance' => 0.2,
                'rounding' => 1,
                'bgcolor' => 'auto',
                'color' => 'auto'
        ];
        $potconfig = array_merge($potconfig, $options);

        $cache = _image_valeurs_trans($img, "image_potrace-$width_thumb-".json_encode($potconfig), "svg");
        if (!$cache) {
                return false;
        }
        // facile !
        if ($cache['format_source'] === 'svg'){
                return $img;
        }

        if ($cache["creer"]) {
                $fichier = $cache["fichier"];
                $dest = $cache["fichier_dest"];

                if (!@file_exists($fichier)) {
                        return false;
                }

                $thumb = image_reduire($img,$width_thumb);
                $source = extraire_attribut($thumb, 'src');

                if ($potconfig['bgcolor'] === 'auto' or $potconfig['color'] === 'auto') {
                        $palette = extraire_palette_couleurs($img, 5, 32);

                        $couleur_bg = array_shift($palette);
                        $couleur_1 = reset($palette);
                        if (couleur_luminance_relative($couleur_bg) < couleur_luminance_relative($couleur_1)) {
                                $couleur_1 = $couleur_bg;
                                $couleur_bg = reset($palette);
                        }
                        $couleur_bg = '#'.ltrim(couleur_eclaircir_si_foncee($couleur_bg),'#');
                        $couleur_1 = '#'.ltrim(couleur_foncer_si_claire($couleur_1),'#');
                }
                if ($potconfig['bgcolor'] !== 'auto') {
                        $couleur_bg = $potconfig['bgcolor'];
                }
                if ($potconfig['color'] !== 'auto') {
                        $couleur_1 = $potconfig['color'];
                }

                $rounding = $potconfig['rounding'];
                unset($potconfig['rounding']);

                $pot = new Potracio();
                $pot->loadImageFromFile($source);
                $pot->setParameter($potconfig);

                $pot->process();
                $coeffSize = 1;
                if ($rounding !== false and $rounding !== 'off') {
                        if (strpos($rounding, 'width=') === 0) {
                                $coeffSize = intval(substr($rounding,6)) / $width_thumb;
                                $rounding = false;
                        }
                        else {
                                $rounding = intval($rounding);
                                while ($rounding-->0) {
                                        $coeffSize *= 10;
                                }
                        }
                }
                $svg_image = $pot->getSVG($coeffSize);

                $svg_image = explode('>', $svg_image, 2);

                $t = $svg_image[0] . '>';
                $w = extraire_attribut($t, "width");
                $h = extraire_attribut($t, "height");

                $svg_image[0] = "<svg viewBox=\"0 0 $w $h\" xmlns=\"http://www.w3.org/2000/svg\">";
                if ($couleur_bg !== 'transparent') {
                        $svg_image[0] .= "<rect width=\"100%\" height=\"100%\" fill=\"$couleur_bg\"/>";
                }

                // optimize the size : round all points to integer
                if ($rounding !== false and $rounding !== 'off'){
                        $svg_image[1] = preg_replace_callback(",\b(\d+\.\d+)\b,ims", "_svg_round_point", $svg_image[1]);
                }
                $svg_image[1] = preg_replace(",(\s)\s+,", "\\1", $svg_image[1]);
                $svg_image[1] = str_replace("black", $couleur_1, $svg_image[1]);
                $svg_image = $svg_image[0] . $svg_image[1];

                ecrire_fichier($dest, $svg_image);
        }

        if (!@file_exists($dest)) {
                return false;
        }

        return _image_ecrire_tag($cache, array('src' => $cache["fichier_dest"]));
}

if (!function_exists('_svg_round_point')) {
        function _svg_round_point($m) {
                return round($m[0]);
        }
}