implemented Canvas and FileWriter for PPM

src/Canvas/Canvas.php

@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ItsAMirko\RayTracer\Canvas;
+
+use ItsAMirko\RayTracer\Primitives\Color;
+use OutOfBoundsException;
+
+class Canvas
+{
+    /**
+     * @var int
+     */
+    private $width;
+    
+    /**
+     * @var int
+     */
+    private $height;
+    
+    /**
+     * @var Color[][]
+     */
+    private $pixels;
+    
+    
+    /**
+     * Canvas constructor.
+     *
+     * @param int $width
+     * @param int $height
+     */
+    public function __construct(int $width, int $height)
+    {
+        $this->width  = $width;
+        $this->height = $height;
+    }
+    
+    
+    /**
+     * @return int
+     */
+    public function width(): int
+    {
+        return $this->width;
+    }
+    
+    
+    /**
+     * @return int
+     */
+    public function height(): int
+    {
+        return $this->height;
+    }
+    
+    
+    /**
+     * @return Color[][]
+     */
+    public function pixels(): array
+    {
+        return $this->pixels;
+    }
+    
+    
+    /**
+     * @param int   $x
+     * @param int   $y
+     * @param Color $color
+     */
+    public function addPixel(int $x, int $y, Color $color): void
+    {
+        if ($x < 0 || $x >= $this->width) {
+            throw new OutOfBoundsException('Invalid position for x provided. Expected integer between 0 and '
+                                           . ($this->width - 1) . ', but got ' . $x);
+        } elseif ($y < 0 || $y >= $this->height) {
+            throw new OutOfBoundsException('Invalid position for y provided. Expected integer between 0 and '
+                                           . ($this->height - 1) . ', but got ' . $y);
+        }
+        
+        $this->pixels[$x][$y] = $color;
+    }
+}

src/Canvas/CanvasPpmFileWriter.php

@@ -0,0 +1,99 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ItsAMirko\RayTracer\Canvas;
+
+use League\Flysystem\FilesystemInterface;
+use function strlen;
+use const PHP_EOL;
+
+/**
+ * Class CanvasPpmFileWriter
+ *
+ * @package ItsAMirko\RayTracer\Canvas
+ */
+class CanvasPpmFileWriter
+{
+    /**
+     * Defines the maximal number of chars per line in the file.
+     */
+    private const MAX_CHARS_PER_LINE = 70;
+    
+    /**
+     * @var FilesystemInterface
+     */
+    private $filesystem;
+    
+    
+    /**
+     * CanvasFileWriter constructor.
+     *
+     * @param FilesystemInterface $filesystem
+     */
+    public function __construct(FilesystemInterface $filesystem)
+    {
+        $this->filesystem = $filesystem;
+    }
+    
+    
+    /**
+     * @param Canvas $canvas
+     * @param string $filename
+     */
+    public function createFile(Canvas $canvas, string $filename): void
+    {
+        $content = $this->getFileHeader($canvas);
+        $content .= $this->getImageContent($canvas);
+        
+        $this->filesystem->put($filename, $content);
+    }
+    
+    
+    /**
+     * @param Canvas $canvas
+     *
+     * @return string
+     */
+    private function getFileHeader(Canvas $canvas): string
+    {
+        return 'P3' . PHP_EOL . $canvas->width() . ' ' . $canvas->height() . PHP_EOL . '255' . PHP_EOL;
+    }
+    
+    
+    /**
+     * @param Canvas $canvas
+     *
+     * @return string
+     */
+    private function getImageContent(Canvas $canvas): string
+    {
+        $content = '';
+        $pixels  = $canvas->pixels();
+        
+        for ($y = 0; $y < $canvas->height(); $y++) {
+            $rowContent = '';
+            for ($x = 0; $x < $canvas->width(); $x++) {
+                foreach (['red', 'green', 'blue'] as $color) {
+                    $colorHex = '0';
+                    if (isset($pixels[$x][$y]) && $color === 'red') {
+                        $colorHex = $pixels[$x][$y]->redAsHex();
+                    } elseif (isset($pixels[$x][$y]) && $color === 'green') {
+                        $colorHex = $pixels[$x][$y]->greenAsHex();
+                    } elseif (isset($pixels[$x][$y]) && $color === 'blue') {
+                        $colorHex = $pixels[$x][$y]->blueAsHex();
+                    }
+                    
+                    if (strlen($rowContent . $colorHex) > self::MAX_CHARS_PER_LINE) {
+                        $content    .= trim($rowContent) . PHP_EOL;
+                        $rowContent = '';
+                    }
+                    $rowContent .= $colorHex . ' ';
+                }
+            }
+            $content .= trim($rowContent) . PHP_EOL;
+        }
+        
+        return $content;
+    }
+}

tests/Canvas/CanvasPpmFileWriterTest.php

@@ -0,0 +1,122 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ItsAMirko\RayTracer\Canvas;
+
+use ItsAMirko\RayTracer\Primitives\Color;
+use League\Flysystem\FilesystemInterface;
+use PHPUnit\Framework\TestCase;
+use function explode;
+use const PHP_EOL;
+
+class CanvasPpmFileWriterTest extends TestCase
+{
+    /**
+     * @var FilesystemInterface
+     */
+    private $filesystem;
+    
+    /**
+     * @var CanvasPpmFileWriter
+     */
+    private $fileWriter;
+    
+    
+    protected function setUp(): void
+    {
+        parent::setUp();
+        
+        $this->filesystem = $this->createMock(FilesystemInterface::class);
+        
+        $this->fileWriter = new CanvasPpmFileWriter($this->filesystem);
+    }
+    
+    
+    public function testWritesPPMHeader(): void
+    {
+        $expectedFilename     = 'my_canvas.ppm';
+        $expectedContentLines = [
+            0 => 'P3',
+            1 => '5 3',
+            2 => '255',
+        ];
+        
+        $this->filesystem->expects($this->once())
+                         ->method('put')
+                         ->with($expectedFilename, $this->checkFileContentCallback($expectedContentLines));
+        
+        $canvas = new Canvas(5, 3);
+        $this->fileWriter->createFile($canvas, $expectedFilename);
+    }
+    
+    
+    public function testWritesPixels(): void
+    {
+        $expectedFilename     = 'my_canvas.ppm';
+        $expectedContentLines = [
+            3 => '255 0 0 0 0 0 0 0 0 0 0 0 0 0 0',
+            4 => '0 0 0 0 0 0 0 128 0 0 0 0 0 0 0',
+            5 => '0 0 0 0 0 0 0 0 0 0 0 0 0 0 255',
+        ];
+        
+        $this->filesystem->expects($this->once())
+                         ->method('put')
+                         ->with($expectedFilename, $this->checkFileContentCallback($expectedContentLines));
+        
+        $canvas = new Canvas(5, 3);
+        $canvas->addPixel(0, 0, new Color(1.5, 0.0, 0.0));
+        $canvas->addPixel(2, 1, new Color(0.0, 0.5, 0.0));
+        $canvas->addPixel(4, 2, new Color(-0.5, 0.0, 1.0));
+        
+        $this->fileWriter->createFile($canvas, $expectedFilename);
+    }
+    
+    
+    public function testSplitsLongLinesOfPixels(): void
+    {
+        $expectedFilename     = 'my_canvas.ppm';
+        $expectedContentLines = [
+            3 => '255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204',
+            4 => '153 255 204 153 255 204 153 255 204 153 255 204 153',
+            5 => '255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204',
+            6 => '153 255 204 153 255 204 153 255 204 153 255 204 153',
+        ];
+        
+        $this->filesystem->expects($this->once())
+                         ->method('put')
+                         ->with($expectedFilename, $this->checkFileContentCallback($expectedContentLines));
+        
+        $canvas = new Canvas(10, 2);
+        for ($i = 0; $i < 10; $i++) {
+            $canvas->addPixel($i, 0, new Color(1, 0.8, 0.6));
+            $canvas->addPixel($i, 1, new Color(1, 0.8, 0.6));
+        }
+        
+        $this->fileWriter->createFile($canvas, $expectedFilename);
+    }
+    
+    
+    /**
+     * Returns a callback to check the content of the PPM file
+     *
+     * @param array $expectedContentLines
+     *
+     * @return callable
+     */
+    private function checkFileContentCallback(array $expectedContentLines)
+    {
+        return $this->callback(function (
+            string $content
+        ) use ($expectedContentLines): bool {
+            $actualContentLines = explode(PHP_EOL, $content);
+            foreach ($expectedContentLines as $line => $expectedContent) {
+                if ($expectedContent !== $actualContentLines[$line]) {
+                    return false;
+                }
+            }
+            
+            return true;
+        });
+    }
+}

tests/Canvas/CanvasTest.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ItsAMirko\RayTracer\Canvas;
+
+use Exception;
+use ItsAMirko\RayTracer\Primitives\Color;
+use OutOfBoundsException;
+use PHPUnit\Framework\TestCase;
+use function random_int;
+
+class CanvasTest extends TestCase
+{
+    /**
+     * @throws Exception
+     */
+    public function testProvidesDimensions(): void
+    {
+        $width  = random_int(1, 100);
+        $height = random_int(1, 100);
+        
+        $canvas = new Canvas($width, $height);
+        
+        $this->assertSame($width, $canvas->width());
+        $this->assertSame($height, $canvas->height());
+    }
+    
+    
+    public function testProvidesItsPixels(): void
+    {
+        $canvas = new Canvas(2, 2);
+        $canvas->addPixel(0, 0, new Color(1.0, 0.0, 0.0));
+        $canvas->addPixel(0, 1, new Color(0.0, 1.0, 0.0));
+        $canvas->addPixel(1, 1, new Color(0.0, 0.0, 1.0));
+        
+        $expectedPixels = [
+            0 => [
+                0 => new Color(1.0, 0.0, 0.0),
+                1 => new Color(0.0, 1.0, 0.0),
+            ],
+            1 => [
+                1 => new Color(0.0, 0.0, 1.0),
+            ],
+        ];
+        
+        $this->assertEquals($expectedPixels, $canvas->pixels());
+    }
+    
+    
+    public function testThrowsExceptionIfPixelToAddIsOutOfBounds(): void
+    {
+        $this->expectException(OutOfBoundsException::class);
+        
+        $canvas = new Canvas(1, 1);
+        $canvas->addPixel(1, 1, new Color(1.0, 0.0, 0.0));
+    }
+}