SVG.php

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<?php
 
declare(strict_types=1);
 
namespace ILIAS\ResourceStorage\Flavour\Machine\DefaultMachines\Extract;
 
use ILIAS\ResourceStorage\Flavour\Definition\PagesToExtract;
use ILIAS\Filesystem\Stream\Stream;
use ILIAS\ResourceStorage\Flavour\Machine\DefaultMachines\ImageSizeCalculator;
 
class SVG implements Extractor
{
    use ImageSizeCalculator;
 
    private bool $pattern = false;
 
    public function readImage(\Imagick $img, Stream $stream, PagesToExtract $definition): \Imagick
    {
        $img->readImageBlob(
            $this->prescaleSVG((string) $stream, $definition->getMaxSize())
        );
 
        // add pattern to background
        if ($this->pattern) {
            $pattern = new \Imagick();
            $x = 10;
            $pattern->readImageBlob(
                '<?xml version="1.0" encoding="UTF-8"?><svg id="Ebene_2" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 '
                . ($x * 2) . ' ' . ($x * 2) . '"><defs><style>.cls-1{fill:#afafaf;}.cls-1,.cls-2{stroke-width:0px;}.cls-2{fill:#e8e8e8;}</style></defs><g id="Ebene_1-2"><rect class="cls-1" width="'
                . $x . '" height="' . $x . '"/><rect class="cls-2" y="' . $x . '" width="' . $x . '" height="' . $x
                . '"/><rect class="cls-1" x="' . $x . '" y="' . $x . '" width="' . $x . '" height="' . $x
                . '"/><rect class="cls-2" x="' . $x . '" width="' . $x . '" height="' . $x . '"/></g></svg>'
            );
            $pattern = $img->textureImage($pattern);
            $pattern->compositeImage(
                $img,
                \Imagick::COMPOSITE_OVER,
                0,
                0
            );
            $img = $pattern;
        }
 
        return $img;
    }
 
    public function getBackground(): \ImagickPixel
    {
        return new \ImagickPixel('none');
    }
 
    public function getAlphaChannel(): int
    {
        return \Imagick::ALPHACHANNEL_ACTIVATE;
    }
 
    public function getRemoveColor(): ?\ImagickPixel
    {
        return new \ImagickPixel('transparent');
    }
 
    public function getResolution(): int
    {
        return 96;
    }
 
    public function getTargetFormat(): string
    {
        return $this->pattern ? 'jpg' : 'png64';
    }
 
    private function prescaleSVG(string $svg_content, int $max_length): string
    {
        try {
            $dom = new \DOMDocument();
            $dom->loadXML($svg_content);
            $svg = $dom->documentElement;
 
            // Get Viewbox if available
            $viewbox = $svg->getAttribute('viewBox');
            if ($viewbox === '') {
                return $svg_content;
            }
            $viewbox = explode(' ', $viewbox);
            $width = (float) ($viewbox[2] ?? 0);
            $height = (float) ($viewbox[3] ?? 0);
 
            if ($width === 0 || $height === 0) {
                return $svg_content;
            }
 
            [$new_width, $new_height] = $this->calculateWidthHeight(
                ceil($width),
                ceil($height),
                $max_length
            );
            $svg->setAttribute('width', (string) $new_width);
            $svg->setAttribute('height', (string) $new_height);
 
            return $dom->saveXML($svg);
        } catch (\Throwable) {
            return $svg_content;
        }
    }
}