Merge pull request #34 from mike42/feature/17-read-gif

Correct some GIF errors

src/Mike42/GfxPhp/Codec/Gif/GifGraphicsBlock.php

@@ -48,10 +48,18 @@ public static function fromBin(DataInputStream $in) : GifGraphicsBlock
             $blockId = $peek[0];
             $extensionId = $peek[1];
         }
-        if ($blockId == GifData::GIF_EXTENSION && $extensionId == GifData::GIF_EXTENSION_APPLICATION) {
-            // ImageMagick drops an 'application' block here, which we can discard.
-            // We would need a slight re-structure to record this correctly.
-            $application = GifApplicationExt::fromBin($in);
+        while ($blockId == GifData::GIF_EXTENSION && $extensionId != GifData::GIF_EXTENSION_PLAINTEXT) {
+            // We would need a slight re-structure to record these blocks correctly.
+            if ($extensionId == GifData::GIF_EXTENSION_APPLICATION) {
+                // ImageMagick drops an 'application' block here, which we can discard (gfx-php does not use it at this stage)
+                GifApplicationExt::fromBin($in);
+            } else if ($extensionId == GifData::GIF_EXTENSION_COMMENT) {
+                // Also GIMP places a 'comment' block here.
+                GifCommentExt::fromBin($in);
+            } else {
+                // And who knows what else we will have to skip. This should cover it anyway.
+                GifUnknownExt::fromBin($in);
+            }
             $peek = $in -> peek(2);
             $blockId = $peek[0];
             $extensionId = $peek[1];

src/Mike42/GfxPhp/Codec/GifCodec.php

@@ -50,7 +50,7 @@ public function encode(RasterImage $image, string $format): string
         // Transparent color for graphic control
         $transparentColorFlag = 0x00;
         $transparentColor = 0;
-        if ($image -> getTransparentColor() !== null) {
+        if ($image -> getTransparentColor() >= 0) {
             $transparentColor = $image -> getTransparentColor() & 0xFF;
             $transparentColorFlag = 0x01;
         }

src/Mike42/GfxPhp/Image.php

@@ -16,9 +16,13 @@ class Image
 
     public static function fromFile(string $filename) : RasterImage
     {
-        $blob = file_get_contents($filename);
+        // Attempt to catch the cause of any errors
+        error_clear_last();
+        $blob = @file_get_contents($filename);
         if ($blob === false) {
-            throw new \Exception("Could not retrieve image data from '$filename'. Check that the file exists and can be read.");
+            $e = error_get_last();
+            $error = (isset($e) && isset($e['message']) && $e['message'] != "") ? $e['message'] : "Check that the file exists and can be read.";
+            throw new \Exception("Could not retrieve image data from '$filename'. $error");
         }
         return self::fromBlob($blob, $filename);
     }

src/Mike42/GfxPhp/IndexedRasterImage.php

@@ -13,7 +13,7 @@ class IndexedRasterImage extends AbstractRasterImage
 
     protected $palette;
 
-    protected $transparentColor = null;
+    protected $transparentColor = -1;
 
     protected function __construct($width, $height, array $data, int $maxVal, array $palette)
     {
@@ -127,7 +127,7 @@ public function toIndexed(): IndexedRasterImage
 
     public function indexToRgb(int $index)
     {
-        if ($index == $this -> transparentColor) {
+        if ($index === $this -> transparentColor) {
             // White
             return [255, 255, 255];
         }
@@ -150,12 +150,12 @@ public function rgbToIndex(array $rgb)
         return 0;
     }
 
-    public function getTransparentColor()
+    public function getTransparentColor() : int
     {
         return $this -> transparentColor;
     }
 
-    public function setTransparentColor(int $color = null)
+    public function setTransparentColor(int $color)
     {
         $this -> transparentColor = $color;
     }

test/integration/PngsuiteTest.php

@@ -10,7 +10,7 @@
  * Simple check that all files in pngsuite are correctly accepted or rejected, and contain
  * correct width.
  */
-class Pngsuite extends TestCase
+class PngsuiteTest extends TestCase
 {
     function loadImage(string $filename) {
         return Image::fromFile(__DIR__ . "/../resources/pngsuite/$filename");

test/integration/SmallFileTest.php

@@ -0,0 +1,77 @@
+<?php
+
+use Mike42\GfxPhp\Image;
+use PHPUnit\Framework\TestCase;
+
+class SmallFileTest extends TestCase
+{
+    function loadImage(string $filename) {
+        $img = Image::fromFile(__DIR__ . "/../resources/small-files/$filename");
+        return $img -> toBlackAndWhite();
+    }
+
+    function testWhite() {
+        $expected = " \n";
+        $width = 1;
+        $height = 1;
+        foreach(['canvas_white.gif', 'canvas_white.png'] as $fn) { // Also jpg and bmp
+            $img = $this -> loadImage($fn);
+            $this -> assertEquals($expected, $img -> toString());
+            $this -> assertEquals($height, $img -> getHeight());
+            $this -> assertEquals($width, $img -> getWidth());
+        }
+    }
+
+    function testBlack() {
+        $expected = "▀\n";
+        $width = 1;
+        $height = 1;
+        foreach(['canvas_black.gif', 'canvas_black.png'] as $fn) { // Also jpg and bmp
+            $img = $this -> loadImage($fn);
+            $this -> assertEquals($expected, $img -> toString());
+            $this -> assertEquals($height, $img -> getHeight());
+            $this -> assertEquals($width, $img -> getWidth());
+        }
+    }
+
+    function testBlackWhite() {
+        $expected = "▀▀\n";
+        $width = 2;
+        $height = 2;
+        foreach(['black_white.gif', 'black_white.png'] as $fn) { // Also jpg and bmp
+            $img = $this -> loadImage($fn);
+            $this -> assertEquals($expected, $img -> toString());
+            $this -> assertEquals($height, $img -> getHeight());
+            $this -> assertEquals($width, $img -> getWidth());
+        }
+    }
+
+    function testBlackTransparent() {
+        $expected = "▀▀\n";
+        $width = 2;
+        $height = 2;
+        foreach(['black_transparent.gif', 'black_transparent.png'] as $fn) { // Also jpg and bmp
+            $img = $this -> loadImage($fn);
+            $this -> assertEquals($expected, $img -> toString());
+            $this -> assertEquals($height, $img -> getHeight());
+            $this -> assertEquals($width, $img -> getWidth());
+        }
+    }
+
+    function testBlackWhiteTall() {
+        $expected = "██\n" .
+                    "██\n" .
+                    "██\n" .
+                    "██\n" .
+                    "  \n" .
+                    "  \n" .
+                    "  \n" .
+                    "  \n";
+        $width = 2;
+        $height = 16;
+        $img = $this -> loadImage('black_white_tall.png');
+        $this -> assertEquals($expected, $img -> toString());
+        $this -> assertEquals($height, $img -> getHeight());
+        $this -> assertEquals($width, $img -> getWidth());
+    }
+}

test/resources/small-files/README.md

@@ -0,0 +1,6 @@
+# Small files
+
+These test files were produded for `escpos-php`.
+
+The same file should have the same representation in black & white from any source format.
+

test/unit/ImageTest.php

@@ -0,0 +1,12 @@
+<?php
+
+use Mike42\GfxPhp\Image;
+use PHPUnit\Framework\TestCase;
+
+class ImageTest extends TestCase
+{
+    public function testBadFilename() {
+        $this -> expectException(Exception::class);
+        Image::fromFile("not a real file");
+    }
+}