Add support for PNG save quality

lib/Imagine/GD/Command/Save.php

@@ -69,6 +69,10 @@ public function process(\Imagine\Image $image)
         $path = $this->path ?: $image->getPath();
         $saveParams = array_merge(array($image->getResource(), $path), $this->saveParams);
 
+        if(array_key_exists('quality', $saveParams)) {
+            $saveParams['quality'] = Utils::getSaveQuality($this->type ?: $image->getType(), $saveParams['quality']);
+        }
+
         if (! is_dir($pathDir = dirname($path))) {
             if (! @mkdir($pathDir, 0777, true)) {
                 throw new \RuntimeException('Cannot create directory: ' . $pathDir);

lib/Imagine/GD/Utils.php

@@ -53,6 +53,28 @@ public static function getSaveFunction($type)
         }
     }
 
+    /**
+     * Get the save quality for an image type.
+     *
+     * @param int $type
+     * @param int $quality between 0 and 100 inclusive
+     * @return int
+     * @throws \InvalidArgumentException
+     */
+    public static function getSaveQuality($type, $quality)
+    {
+        if($quality < 0 || $quality > 100) {
+            throw new \InvalidArgumentException(sprintf('Save quality must be comprised between 0 and 100 inclusive, "%d" given'));
+        }
+
+        if(IMAGETYPE_PNG === $type) {
+            // Transform quality to PNG compression level
+            $quality = abs(($quality - 100) / 11.111111);
+        }
+
+        return round($quality);
+    }
+
     /**
      * Checks whether the parameter is a valid GD image resource.
      *
@@ -93,4 +115,4 @@ public static function createResource($width, $height, $type = null)
 
         return $resource;
     }
-}
+}

tests/Imagine/GD/Command/SaveTest.php

@@ -6,9 +6,69 @@
 
 class SaveTest extends \PHPUnit_Framework_TestCase
 {
+    const IMG_PNG = 'tests/fixtures/land.png';
+    const IMG_JPEG = 'tests/fixtures/land.jpg';
+
+    protected $png;
+    protected $jpeg;
+    protected $tmpFile;
+
+    public function setUp()
+    {
+        parent::setUp();
+        $this->png = new \Imagine\Image(self::IMG_PNG);
+        $this->jpeg = new \Imagine\Image(self::IMG_JPEG);
+        $this->tmpFile = sys_get_temp_dir().'/'.uniqid();
+    }
+
+    public function tearDown()
+    {
+        if(file_exists($this->tmpFile)) {
+            unlink($this->tmpFile);
+        }
+    }
+
     public function testSave()
     {
-        // TODO: implement unit tests for save command
-        $this->markTestIncomplete();
+        $this->assertFalse(file_exists($this->tmpFile));
+        $command = new Save($this->tmpFile);
+        $command->process($this->png);
+        $this->assertTrue(file_exists($this->tmpFile));
+    }
+
+    public function testSaveJpegWithHighQuality()
+    {
+        $originalFileSize = filesize(self::IMG_JPEG);
+        $command = new Save($this->tmpFile, null, array('quality' => 100));
+        $command->process($this->jpeg);
+        $newFileSize = filesize($this->tmpFile);
+        $this->assertGreaterThanOrEqual($originalFileSize, $newFileSize);
+    }
+
+    public function testSaveJpegWithLowQuality()
+    {
+        $originalFileSize = filesize(self::IMG_JPEG);
+        $command = new Save($this->tmpFile, null, array('quality' => 10));
+        $command->process($this->jpeg);
+        $newFileSize = filesize($this->tmpFile);
+        $this->assertLessThanOrEqual($originalFileSize, $newFileSize);
+    }
+
+    public function testSavePngWithHighQuality()
+    {
+        $originalFileSize = filesize(self::IMG_PNG);
+        $command = new Save($this->tmpFile, null, array('quality' => 100));
+        $command->process($this->png);
+        $newFileSize = filesize($this->tmpFile);
+        $this->assertGreaterThanOrEqual($originalFileSize, $newFileSize);
+    }
+
+    public function testSavePngWithLowQuality()
+    {
+        $originalFileSize = filesize(self::IMG_PNG);
+        $command = new Save($this->tmpFile, null, array('quality' => 0));
+        $command->process($this->png);
+        $newFileSize = filesize($this->tmpFile);
+        $this->assertLessThanOrEqual($originalFileSize, $newFileSize);
     }
 }

tests/Imagine/GD/UtilsTest.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Imagine\GD;
+
+require_once 'tests/Imagine/TestInit.php';
+
+class UtilsTest extends \PHPUnit_Framework_TestCase
+{
+    public function testSaveQualityJpeg()
+    {
+        $this->assertEquals(20, Utils::getSaveQuality(IMAGETYPE_JPEG, 20));
+        $this->assertEquals(100, Utils::getSaveQuality(IMAGETYPE_JPEG, 100));
+    }
+
+    public function testSaveQualityPng()
+    {
+        $this->assertEquals(7, Utils::getSaveQuality(IMAGETYPE_PNG, 20));
+        $this->assertEquals(9, Utils::getSaveQuality(IMAGETYPE_PNG, 0));
+        $this->assertEquals(0, Utils::getSaveQuality(IMAGETYPE_PNG, 100));
+    }
+}