fix(svg): generate unique IDs for gradients based on their properties (…

…#187)

Closes #186

src/Renderer/Image/SvgImageBackEnd.php

@@ -316,7 +316,11 @@ private function createGradientFill(Gradient $gradient, float $x, float $y, floa
                 break;
         }
 
-        $id = sprintf('g%d', ++$this->gradientCount);
+        $toBeHashed = $this->getColorString($startColor) . $this->getColorString($endColor) . $gradient->getType();
+        if ($startColor instanceof Alpha) {
+            $toBeHashed .= (string) $startColor->getAlpha();
+        }
+        $id = sprintf('g%d-%s', ++$this->gradientCount, hash('xxh64', $toBeHashed));
         $this->xmlWriter->writeAttribute('id', $id);
 
         $this->xmlWriter->startElement('stop');

test/Integration/SVGRenderingTest.php

@@ -0,0 +1,70 @@
+<?php
+
+declare(strict_types=1);
+
+namespace BaconQrCodeTest\Integration;
+
+use BaconQrCode\Renderer\Color\Rgb;
+use BaconQrCode\Renderer\Image\SvgImageBackEnd;
+use BaconQrCode\Renderer\ImageRenderer;
+use BaconQrCode\Renderer\RendererStyle\EyeFill;
+use BaconQrCode\Renderer\RendererStyle\Fill;
+use BaconQrCode\Renderer\RendererStyle\Gradient;
+use BaconQrCode\Renderer\RendererStyle\GradientType;
+use BaconQrCode\Renderer\RendererStyle\RendererStyle;
+use BaconQrCode\Writer;
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\TestCase;
+
+#[Group('integration')]
+final class SVGRenderingTest extends TestCase
+{
+    public function testGenericQrCode(): void
+    {
+        $renderer = new ImageRenderer(
+            new RendererStyle(400),
+            new SvgImageBackEnd()
+        );
+        $writer = new Writer($renderer);
+
+        $svgCode = $writer->writeString('Hello World!');
+        $expected = file_get_contents(__DIR__.'/__snapshots__/files/SVGRenderingTest__testGenericQrCode__1.svg');
+
+        $this->assertEquals($expected, $svgCode);
+    }
+
+    //    SVGRenderingTest__testQrWithGradientGeneratesDifferentIdsForDifferentGradients_horizontal
+    //SVGRenderingTest__testQrWithGradientGeneratesDifferentIdsForDifferentGradients_vertical
+    public function testQrWithGradientGeneratesDifferentIdsForDifferentGradients()
+    {
+        $types = ['HORIZONTAL', 'VERTICAL'];
+        foreach ($types as $type) {
+            $gradient = new Gradient(
+                new Rgb(0, 0, 0),
+                new Rgb(255, 0, 0),
+                GradientType::$type()
+            );
+            $renderer = new ImageRenderer(
+                new RendererStyle(
+                    size: 400,
+                    fill: Fill::withForegroundGradient(
+                        new Rgb(255, 255, 255),
+                        $gradient,
+                        EyeFill::inherit(),
+                        EyeFill::inherit(),
+                        EyeFill::inherit()
+                    )
+                ),
+                new SvgImageBackEnd()
+            );
+            $writer = new Writer($renderer);
+            $qr = $writer->writeString('Hello World!');
+            $expectedFile = __DIR__ . '/__snapshots__/files/';
+            $expectedFile .= 'SVGRenderingTest__testQrWithGradientGeneratesDifferentIdsForDifferentGradients__';
+            $expectedFile .= strtolower($type) . '.svg';
+            $expected = file_get_contents($expectedFile);
+
+            $this->assertEquals($expected, $qr);
+        }
+    }
+}