Add tests for progessive jpeg encoding

tests/Traits/CanDetectProgressiveJpeg.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Intervention\Image\Tests\Traits;
+
+use Intervention\Image\Traits\CanBuildFilePointer;
+
+trait CanDetectProgressiveJpeg
+{
+    use CanBuildFilePointer;
+
+    /**
+     * Checks if the given image data is progressive encoded Jpeg format
+     *
+     * @param string $imagedata
+     * @return bool
+     */
+    private function isProgressiveJpeg(string $imagedata): bool
+    {
+        $f = $this->buildFilePointer($imagedata);
+
+        while (!feof($f)) {
+            if (unpack('C', fread($f, 1))[1] !== 0xff) {
+                return false;
+            }
+
+            $blockType = unpack('C', fread($f, 1))[1];
+
+            switch (true) {
+                case $blockType == 0xd8:
+                case $blockType >= 0xd0 && $blockType <= 0xd7:
+                    break;
+
+                case $blockType == 0xc0:
+                    fclose($f);
+                    return false;
+
+                case $blockType == 0xc2:
+                    fclose($f);
+                    return true;
+
+                case $blockType == 0xd9:
+                    break 2;
+
+                default:
+                    $blockSize = unpack('n', fread($f, 2))[1];
+                    fseek($f, $blockSize - 2, SEEK_CUR);
+                    break;
+            }
+        }
+
+        fclose($f);
+
+        return false;
+    }
+}

tests/Unit/Drivers/Gd/Encoders/JpegEncoderTest.php

@@ -8,17 +8,29 @@
 use PHPUnit\Framework\Attributes\RequiresPhpExtension;
 use Intervention\Image\Encoders\JpegEncoder;
 use Intervention\Image\Tests\GdTestCase;
+use Intervention\Image\Tests\Traits\CanDetectProgressiveJpeg;
 
 #[RequiresPhpExtension('gd')]
 #[CoversClass(\Intervention\Image\Encoders\JpegEncoder::class)]
 #[CoversClass(\Intervention\Image\Drivers\Gd\Encoders\JpegEncoder::class)]
 final class JpegEncoderTest extends GdTestCase
 {
+    use CanDetectProgressiveJpeg;
+
     public function testEncode(): void
     {
         $image = $this->createTestImage(3, 2);
         $encoder = new JpegEncoder(75);
         $result = $encoder->encode($image);
         $this->assertMediaType('image/jpeg', (string) $result);
     }
+
+    public function testEncodeProgressive(): void
+    {
+        $image = $this->createTestImage(3, 2);
+        $encoder = new JpegEncoder(progressive: true);
+        $result = $encoder->encode($image);
+        $this->assertMediaType('image/jpeg', (string) $result);
+        $this->assertTrue($this->isProgressiveJpeg((string) $result));
+    }
 }

tests/Unit/Drivers/Imagick/Encoders/JpegEncoderTest.php

@@ -8,17 +8,29 @@
 use PHPUnit\Framework\Attributes\RequiresPhpExtension;
 use Intervention\Image\Encoders\JpegEncoder;
 use Intervention\Image\Tests\ImagickTestCase;
+use Intervention\Image\Tests\Traits\CanDetectProgressiveJpeg;
 
 #[RequiresPhpExtension('imagick')]
 #[CoversClass(\Intervention\Image\Encoders\JpegEncoder::class)]
 #[CoversClass(\Intervention\Image\Drivers\Imagick\Encoders\JpegEncoder::class)]
 final class JpegEncoderTest extends ImagickTestCase
 {
+    use CanDetectProgressiveJpeg;
+
     public function testEncode(): void
     {
         $image = $this->createTestImage(3, 2);
         $encoder = new JpegEncoder(75);
         $result = $encoder->encode($image);
         $this->assertMediaType('image/jpeg', (string) $result);
     }
+
+    public function testEncodeProgressive(): void
+    {
+        $image = $this->createTestImage(3, 2);
+        $encoder = new JpegEncoder(progressive: true);
+        $result = $encoder->encode($image);
+        $this->assertMediaType('image/jpeg', (string) $result);
+        $this->assertTrue($this->isProgressiveJpeg((string) $result));
+    }
 }