QrEps output Update

[danielHPeters]

Hi,
Thanks for this amazing library.
We are using this libray to create QR-codes for print-labels.
Since we are using InDesign when editing these labels, the new QrEps output in the dev branch is a very useful addition, because its easier to import and edit the eps qr-codes in InDesign. In its current form there are some issues though.
When comparing the QR-code generated with other output methods (e.g. png or jpg) the QR-code looked different
when using exact same parameters and data. Upon further investigation we noticed that when removing the 90deg rotation
and mirroring the y-axis, the eps file was correct. We would like to share the changes made (maybe others can improve on the changes as well).

The updated QrEps class also uses a different scaling method so no transforms are necessary.
The drawLightModules option is also implemented.
We also updated the getModuleValue function to accept an RGB array (the int/byte hex method was not practical for us to work with).

Here's the updated code:

<?php
/**
 * Class QREps
 *
 * @created      09.05.2022
 * @author       smiley <[email protected]>
 * @copyright    2022 smiley
 * @license      MIT
 */

namespace chillerlan\QRCode\Output;

use function count, date, implode, is_array, sprintf;

/**
 * Encapsulated Postscript (EPS) output
 *
 * @see https://github.com/t0k4rt/phpqrcode/blob/bb29e6eb77e0a2a85bb0eb62725e0adc11ff5a90/qrvect.php#L52-L137
 * @see https://web.archive.org/web/20170818010030/http://wwwimages.adobe.com/content/dam/Adobe/en/devnet/postscript/pdfs/5002.EPSF_Spec.pdf
 * @see https://web.archive.org/web/20210419003859/https://www.adobe.com/content/dam/acom/en/devnet/actionscript/articles/PLRM.pdf
 */
class QREps extends QROutputAbstract {
    /**
     * @inheritDoc
     */
    protected function moduleValueIsValid ($value): bool {
        return is_array($value) && count($value) >= 3;
    }

    /**
     * @inheritDoc
     */
    protected function getModuleValue ($value): array {
       // Convert from 0-255 to 0-1 RGB range
        return [
            $value[0] / 255.0,
            $value[1] / 255.0,
            $value[2] / 255.0
        ];
    }

    /**
     * @inheritDoc
     */
    protected function getDefaultModuleValue (bool $isDark): array {
        return $isDark ? [0.0, 0.0, 0.0] : [1.0, 1.0, 1.0];
    }

    protected function module (int $x, int $y): string {
        if (!$this->options->drawLightModules && !$this->matrix->check($x, $y)) {
            return '';
        } else {
            $top = $this->length - $this->scale; // Actual size - one block = Topmost y pos.
            $outputX = $x * $this->scale;
            $outputY = $top - ($y * $this->scale); // Apparently y axis is inverted (y0 is at bottom and not top) in EPS so we have to switch the y axis here

            return sprintf('%d %d %d %d F', $outputX, $outputY, $this->scale, $this->scale);
        }
    }

    /**
     * @inheritDoc
     */
    public function dump (string $file = null): string {
        $file ??= $this->options->cachefile;

        $eps = [
            // main header
            '%!PS-Adobe-3.0 EPSF-3.0',
            '%%Creator: php-qrcode (https://github.com/chillerlan/php-qrcode)',
            '%%Title: QR Code',
            sprintf('%%%%CreationDate: %1$s', date('c')),
            '%%DocumentData: Clean7Bit',
            '%%LanguageLevel: 3',
            sprintf('%%%%BoundingBox: 0 0 %1$s %1$s', $this->length),
            '%%EndComments',
            // function definitions
            '%%BeginProlog',
            '/F { rectfill } def',
            '/S { setrgbcolor } def',
            '%%EndProlog'
        ];

        // create the path elements
        $paths = $this->collectModules(fn(int $x, int $y): string => $this->module($x, $y));

        foreach ($paths as $M_TYPE => $path) {

            if (empty($path)) {
                continue;
            }

            $eps[] = sprintf('%f %f %f S', ...$this->moduleValues[$M_TYPE]);
            $eps[] = implode("\n", $path);
        }

        // end file
        $eps[] = '%%EOF';

        $data = implode("\n", $eps);

        if ($file !== null) {
            $this->saveToFile($data, $file);
        }

        return $data;
    }
}

[codemasher]

Hey, thank you for your feedback and updates! When i added the EPS output, i thought of it as a gimmick and didn't expect anyone to use this dinosaur of a file format but here we are :D. I'll add and push the changes ASAP - i might change the moduleValueIsValid() method though to check is_numeric() for the values and clamp them between 0 and 255 if necessary (which is what i should have done before in QRGdImage also). Feel free to submit a PR in case of future changes. Cheers!

[codemasher]

Update: 3ed5bbc