tests/phpunit/includes/api/RandomImageGenerator.php

   1 <?php
   2 /**
   3  * RandomImageGenerator -- does what it says on the tin.
   4  * Requires Imagick, the ImageMagick library for PHP, or the command line
   5  * equivalent (usually 'convert').
   6  *
   7  * Because MediaWiki tests the uniqueness of media upload content, and
   8  * filenames, it is sometimes useful to generate files that are guaranteed (or
   9  * at least very likely) to be unique in both those ways. This generates a
  10  * number of filenames with random names and random content (colored triangles).
  11  *
  12  * It is also useful to have fresh content because our tests currently run in a
  13  * "destructive" mode, and don't create a fresh new wiki for each test run.
  14  * Consequently, if we just had a few static files we kept re-uploading, we'd
  15  * get lots of warnings about matching content or filenames, and even if we
  16  * deleted those files, we'd get warnings about archived files.
  17  *
  18  * This can also be used with a cronjob to generate random files all the time.
  19  * I use it to have a constant, never ending supply when I'm testing
  20  * interactively.
  21  *
  22  * @file
  23  * @author Neil Kandalgaonkar <neilk@wikimedia.org>
  24  */
  25
  26 use MediaWiki\Shell\Shell;
  27
  28 /**
  29  * RandomImageGenerator: does what it says on the tin.
  30  * Can fetch a random image, or also write a number of them to disk with random filenames.
  31  */
  32 class RandomImageGenerator {
  33         private $dictionaryFile;
  34         private $minWidth = 400;
  35         private $maxWidth = 800;
  36         private $minHeight = 400;
  37         private $maxHeight = 800;
  38         private $shapesToDraw = 5;
  39
  40         /**
  41          * Orientations: 0th row, 0th column, Exif orientation code, rotation 2x2
  42          * matrix that is opposite of orientation. N.b. we do not handle the
  43          * 'flipped' orientations, which is why there is no entry for 2, 4, 5, or 7.
  44          * Those seem to be rare in real images anyway (we also would need a
  45          * non-symmetric shape for the images to test those, like a letter F).
  46          */
  47         private static $orientations = [
  48                 [
  49                         '0thRow' => 'top',
  50                         '0thCol' => 'left',
  51                         'exifCode' => 1,
  52                         'counterRotation' => [ [ 1, 0 ], [ 0, 1 ] ]
  53                 ],
  54                 [
  55                         '0thRow' => 'bottom',
  56                         '0thCol' => 'right',
  57                         'exifCode' => 3,
  58                         'counterRotation' => [ [ -1, 0 ], [ 0, -1 ] ]
  59                 ],
  60                 [
  61                         '0thRow' => 'right',
  62                         '0thCol' => 'top',
  63                         'exifCode' => 6,
  64                         'counterRotation' => [ [ 0, 1 ], [ 1, 0 ] ]
  65                 ],
  66                 [
  67                         '0thRow' => 'left',
  68                         '0thCol' => 'bottom',
  69                         'exifCode' => 8,
  70                         'counterRotation' => [ [ 0, -1 ], [ -1, 0 ] ]
  71                 ]
  72         ];
  73
  74         public function __construct( $options = [] ) {
  75                 foreach ( [ 'dictionaryFile', 'minWidth', 'minHeight',
  76                         'maxWidth', 'maxHeight', 'shapesToDraw' ] as $property
  77                 ) {
  78                         if ( isset( $options[$property] ) ) {
  79                                 $this->$property = $options[$property];
  80                         }
  81                 }
  82
  83                 // find the dictionary file, to generate random names
  84                 if ( !isset( $this->dictionaryFile ) ) {
  85                         foreach (
  86                                 [
  87                                         '/usr/share/dict/words',
  88                                         '/usr/dict/words',
  89                                         __DIR__ . '/words.txt'
  90                                 ] as $dictionaryFile
  91                         ) {
  92                                 if ( is_file( $dictionaryFile ) && is_readable( $dictionaryFile ) ) {
  93                                         $this->dictionaryFile = $dictionaryFile;
  94                                         break;
  95                                 }
  96                         }
  97                 }
  98                 if ( !isset( $this->dictionaryFile ) ) {
  99                         throw new Exception( "RandomImageGenerator: dictionary file not "
 100                                 . "found or not specified properly" );
 101                 }
 102         }
 103
 104         /**
 105          * Writes random images with random filenames to disk in the directory you
 106          * specify, or current working directory.
 107          *
 108          * @param int $number Number of filenames to write
 109          * @param string $format Optional, must be understood by ImageMagick, such as 'jpg' or 'gif'
 110          * @param string|null $dir Directory, optional (will default to current working directory)
 111          * @return array Filenames we just wrote
 112          */
 113         function writeImages( $number, $format = 'jpg', $dir = null ) {
 114                 $filenames = $this->getRandomFilenames( $number, $format, $dir );
 115                 $imageWriteMethod = $this->getImageWriteMethod( $format );
 116                 foreach ( $filenames as $filename ) {
 117                         $this->{$imageWriteMethod}( $this->getImageSpec(), $format, $filename );
 118                 }
 119
 120                 return $filenames;
 121         }
 122
 123         /**
 124          * Figure out how we write images. This is a factor of both format and the local system
 125          *
 126          * @param string $format (a typical extension like 'svg', 'jpg', etc.)
 127          *
 128          * @throws Exception
 129          * @return string
 130          */
 131         function getImageWriteMethod( $format ) {
 132                 global $wgUseImageMagick, $wgImageMagickConvertCommand;
 133                 if ( $format === 'svg' ) {
 134                         return 'writeSvg';
 135                 } else {
 136                         // figure out how to write images
 137                         global $wgExiv2Command;
 138                         if ( class_exists( 'Imagick' ) && $wgExiv2Command && is_executable( $wgExiv2Command ) ) {
 139                                 return 'writeImageWithApi';
 140                         } elseif ( $wgUseImageMagick
 141                                 && $wgImageMagickConvertCommand
 142                                 && is_executable( $wgImageMagickConvertCommand )
 143                         ) {
 144                                 return 'writeImageWithCommandLine';
 145                         }
 146                 }
 147                 throw new Exception( "RandomImageGenerator: could not find a suitable "
 148                         . "method to write images in '$format' format" );
 149         }
 150
 151         /**
 152          * Return a number of randomly-generated filenames
 153          * Each filename uses two words randomly drawn from the dictionary, like elephantine_spatula.jpg
 154          *
 155          * @param int $number Number of filenames to generate
 156          * @param string $extension Optional, defaults to 'jpg'
 157          * @param string $dir Optional, defaults to current working directory
 158          * @return array Array of filenames
 159          */
 160         private function getRandomFilenames( $number, $extension = 'jpg', $dir = null ) {
 161                 if ( is_null( $dir ) ) {
 162                         $dir = getcwd();
 163                 }
 164                 $filenames = [];
 165                 foreach ( $this->getRandomWordPairs( $number ) as $pair ) {
 166                         $basename = $pair[0] . '_' . $pair[1];
 167                         if ( !is_null( $extension ) ) {
 168                                 $basename .= '.' . $extension;
 169                         }
 170                         $basename = preg_replace( '/\s+/', '', $basename );
 171                         $filenames[] = "$dir/$basename";
 172                 }
 173
 174                 return $filenames;
 175         }
 176
 177         /**
 178          * Generate data representing an image of random size (within limits),
 179          * consisting of randomly colored and sized upward pointing triangles
 180          * against a random background color. (This data is used in the
 181          * writeImage* methods).
 182          *
 183          * @return mixed
 184          */
 185         public function getImageSpec() {
 186                 $spec = [];
 187
 188                 $spec['width'] = mt_rand( $this->minWidth, $this->maxWidth );
 189                 $spec['height'] = mt_rand( $this->minHeight, $this->maxHeight );
 190                 $spec['fill'] = $this->getRandomColor();
 191
 192                 $diagonalLength = sqrt( $spec['width'] ** 2 + $spec['height'] ** 2 );
 193
 194                 $draws = [];
 195                 for ( $i = 0; $i <= $this->shapesToDraw; $i++ ) {
 196                         $radius = mt_rand( 0, $diagonalLength / 4 );
 197                         if ( $radius == 0 ) {
 198                                 continue;
 199                         }
 200                         $originX = mt_rand( -1 * $radius, $spec['width'] + $radius );
 201                         $originY = mt_rand( -1 * $radius, $spec['height'] + $radius );
 202                         $angle = mt_rand( 0, ( 3.141592 / 2 ) * $radius ) / $radius;
 203                         $legDeltaX = round( $radius * sin( $angle ) );
 204                         $legDeltaY = round( $radius * cos( $angle ) );
 205
 206                         $draw = [];
 207                         $draw['fill'] = $this->getRandomColor();
 208                         $draw['shape'] = [
 209                                 [ 'x' => $originX, 'y' => $originY - $radius ],
 210                                 [ 'x' => $originX + $legDeltaX, 'y' => $originY + $legDeltaY ],
 211                                 [ 'x' => $originX - $legDeltaX, 'y' => $originY + $legDeltaY ],
 212                                 [ 'x' => $originX, 'y' => $originY - $radius ]
 213                         ];
 214                         $draws[] = $draw;
 215                 }
 216
 217                 $spec['draws'] = $draws;
 218
 219                 return $spec;
 220         }
 221
 222         /**
 223          * Given [ [ 'x' => 10, 'y' => 20 ], [ 'x' => 30, y=> 5 ] ]
 224          * returns "10,20 30,5"
 225          * Useful for SVG and imagemagick command line arguments
 226          * @param array $shape Array of arrays, each array containing x & y keys mapped to numeric values
 227          * @return string
 228          */
 229         static function shapePointsToString( $shape ) {
 230                 $points = [];
 231                 foreach ( $shape as $point ) {
 232                         $points[] = $point['x'] . ',' . $point['y'];
 233                 }
 234
 235                 return implode( " ", $points );
 236         }
 237
 238         /**
 239          * Based on image specification, write a very simple SVG file to disk.
 240          * Ignores the background spec because transparency is cool. :)
 241          *
 242          * @param array $spec Spec describing background and shapes to draw
 243          * @param string $format File format to write (which is obviously always svg here)
 244          * @param string $filename Filename to write to
 245          *
 246          * @throws Exception
 247          */
 248         public function writeSvg( $spec, $format, $filename ) {
 249                 $svg = new SimpleXmlElement( '<svg/>' );
 250                 $svg->addAttribute( 'xmlns', 'http://www.w3.org/2000/svg' );
 251                 $svg->addAttribute( 'version', '1.1' );
 252                 $svg->addAttribute( 'width', $spec['width'] );
 253                 $svg->addAttribute( 'height', $spec['height'] );
 254                 $g = $svg->addChild( 'g' );
 255                 foreach ( $spec['draws'] as $drawSpec ) {
 256                         $shape = $g->addChild( 'polygon' );
 257                         $shape->addAttribute( 'fill', $drawSpec['fill'] );
 258                         $shape->addAttribute( 'points', self::shapePointsToString( $drawSpec['shape'] ) );
 259                 }
 260
 261                 $fh = fopen( $filename, 'w' );
 262                 if ( !$fh ) {
 263                         throw new Exception( "couldn't open $filename for writing" );
 264                 }
 265                 fwrite( $fh, $svg->asXML() );
 266                 if ( !fclose( $fh ) ) {
 267                         throw new Exception( "couldn't close $filename" );
 268                 }
 269         }
 270
 271         /**
 272          * Based on an image specification, write such an image to disk, using Imagick PHP extension
 273          * @param array $spec Spec describing background and circles to draw
 274          * @param string $format File format to write
 275          * @param string $filename Filename to write to
 276          */
 277         public function writeImageWithApi( $spec, $format, $filename ) {
 278                 // this is a hack because I can't get setImageOrientation() to work. See below.
 279                 global $wgExiv2Command;
 280
 281                 $image = new Imagick();
 282                 /**
 283                  * If the format is 'jpg', will also add a random orientation -- the
 284                  * image will be drawn rotated with triangle points facing in some
 285                  * direction (0, 90, 180 or 270 degrees) and a countering rotation
 286                  * should turn the triangle points upward again.
 287                  */
 288                 $orientation = self::$orientations[0]; // default is normal orientation
 289                 if ( $format == 'jpg' ) {
 290                         $orientation = self::$orientations[array_rand( self::$orientations )];
 291                         $spec = self::rotateImageSpec( $spec, $orientation['counterRotation'] );
 292                 }
 293
 294                 $image->newImage( $spec['width'], $spec['height'], new ImagickPixel( $spec['fill'] ) );
 295
 296                 foreach ( $spec['draws'] as $drawSpec ) {
 297                         $draw = new ImagickDraw();
 298                         $draw->setFillColor( $drawSpec['fill'] );
 299                         $draw->polygon( $drawSpec['shape'] );
 300                         $image->drawImage( $draw );
 301                 }
 302
 303                 $image->setImageFormat( $format );
 304
 305                 // this doesn't work, even though it's documented to do so...
 306                 // $image->setImageOrientation( $orientation['exifCode'] );
 307
 308                 $image->writeImage( $filename );
 309
 310                 // because the above setImageOrientation call doesn't work... nor can I
 311                 // get an external imagemagick binary to do this either... Hacking this
 312                 // for now (only works if you have exiv2 installed, a program to read
 313                 // and manipulate exif).
 314                 if ( $wgExiv2Command ) {
 315                         $command = Shell::command( $wgExiv2Command,
 316                                 '-M',
 317                                 "set Exif.Image.Orientation {$orientation['exifCode']}",
 318                                 $filename
 319                         )->includeStderr();
 320
 321                         $result = $command->execute();
 322                         $retval = $result->getExitCode();
 323                         if ( $retval !== 0 ) {
 324                                 print "Error with $command: $retval, {$result->getStdout()}\n";
 325                         }
 326                 }
 327         }
 328
 329         /**
 330          * Given an image specification, produce rotated version
 331          * This is used when simulating a rotated image capture with Exif orientation
 332          * @param array $spec Returned by getImageSpec
 333          * @param array $matrix 2x2 transformation matrix
 334          * @return array Transformed Spec
 335          */
 336         private static function rotateImageSpec( &$spec, $matrix ) {
 337                 $tSpec = [];
 338                 $dims = self::matrixMultiply2x2( $matrix, $spec['width'], $spec['height'] );
 339                 $correctionX = 0;
 340                 $correctionY = 0;
 341                 if ( $dims['x'] < 0 ) {
 342                         $correctionX = abs( $dims['x'] );
 343                 }
 344                 if ( $dims['y'] < 0 ) {
 345                         $correctionY = abs( $dims['y'] );
 346                 }
 347                 $tSpec['width'] = abs( $dims['x'] );
 348                 $tSpec['height'] = abs( $dims['y'] );
 349                 $tSpec['fill'] = $spec['fill'];
 350                 $tSpec['draws'] = [];
 351                 foreach ( $spec['draws'] as $draw ) {
 352                         $tDraw = [
 353                                 'fill' => $draw['fill'],
 354                                 'shape' => []
 355                         ];
 356                         foreach ( $draw['shape'] as $point ) {
 357                                 $tPoint = self::matrixMultiply2x2( $matrix, $point['x'], $point['y'] );
 358                                 $tPoint['x'] += $correctionX;
 359                                 $tPoint['y'] += $correctionY;
 360                                 $tDraw['shape'][] = $tPoint;
 361                         }
 362                         $tSpec['draws'][] = $tDraw;
 363                 }
 364
 365                 return $tSpec;
 366         }
 367
 368         /**
 369          * Given a matrix and a pair of images, return new position
 370          * @param array $matrix 2x2 rotation matrix
 371          * @param int $x The x-coordinate number
 372          * @param int $y The y-coordinate number
 373          * @return array Transformed with properties x, y
 374          */
 375         private static function matrixMultiply2x2( $matrix, $x, $y ) {
 376                 return [
 377                         'x' => $x * $matrix[0][0] + $y * $matrix[0][1],
 378                         'y' => $x * $matrix[1][0] + $y * $matrix[1][1]
 379                 ];
 380         }
 381
 382         /**
 383          * Based on an image specification, write such an image to disk, using the
 384          * command line ImageMagick program ('convert').
 385          *
 386          * Sample command line:
 387          *  $ convert -size 100x60 xc:rgb(90,87,45) \
 388          *      -draw 'fill rgb(12,34,56)   polygon 41,39 44,57 50,57 41,39' \
 389          *   -draw 'fill rgb(99,123,231) circle 59,39 56,57' \
 390          *   -draw 'fill rgb(240,12,32)  circle 50,21 50,3'  filename.png
 391          *
 392          * @param array $spec Spec describing background and shapes to draw
 393          * @param string $format File format to write (unused by this method but
 394          *   kept so it has the same signature as writeImageWithApi).
 395          * @param string $filename Filename to write to
 396          *
 397          * @return bool
 398          */
 399         public function writeImageWithCommandLine( $spec, $format, $filename ) {
 400                 global $wgImageMagickConvertCommand;
 401
 402                 $args = [
 403                         $wgImageMagickConvertCommand,
 404                         '-size',
 405                         $spec['width'] . 'x' . $spec['height'],
 406                         "xc:{$spec['fill']}",
 407                 ];
 408                 foreach ( $spec['draws'] as $draw ) {
 409                         $fill = $draw['fill'];
 410                         $polygon = self::shapePointsToString( $draw['shape'] );
 411                         $drawCommand = "fill $fill  polygon $polygon";
 412                         $args[] = '-draw';
 413                         $args[] = $drawCommand;
 414                 }
 415                 $args[] = $filename;
 416
 417                 $result = Shell::command( $args )->execute();
 418
 419                 return ( $result->getExitCode() === 0 );
 420         }
 421
 422         /**
 423          * Generate a string of random colors for ImageMagick or SVG, like "rgb(12, 37, 98)"
 424          *
 425          * @return string
 426          */
 427         public function getRandomColor() {
 428                 $components = [];
 429                 for ( $i = 0; $i <= 2; $i++ ) {
 430                         $components[] = mt_rand( 0, 255 );
 431                 }
 432
 433                 return 'rgb(' . implode( ', ', $components ) . ')';
 434         }
 435
 436         /**
 437          * Get an array of random pairs of random words, like
 438          * [ [ 'foo', 'bar' ], [ 'quux', 'baz' ] ];
 439          *
 440          * @param int $number Number of pairs
 441          * @return array Two-element arrays
 442          */
 443         private function getRandomWordPairs( $number ) {
 444                 $lines = $this->getRandomLines( $number * 2 );
 445                 // construct pairs of words
 446                 $pairs = [];
 447                 $count = count( $lines );
 448                 for ( $i = 0; $i < $count; $i += 2 ) {
 449                         $pairs[] = [ $lines[$i], $lines[$i + 1] ];
 450                 }
 451
 452                 return $pairs;
 453         }
 454
 455         /**
 456          * Return N random lines from a file
 457          *
 458          * Will throw exception if the file could not be read or if it had fewer lines than requested.
 459          *
 460          * @param int $number_desired Number of lines desired
 461          *
 462          * @throws Exception
 463          * @return array Array of exactly n elements, drawn randomly from lines the file
 464          */
 465         private function getRandomLines( $number_desired ) {
 466                 $filepath = $this->dictionaryFile;
 467
 468                 // initialize array of lines
 469                 $lines = [];
 470                 for ( $i = 0; $i < $number_desired; $i++ ) {
 471                         $lines[] = null;
 472                 }
 473
 474                 /*
 475                  * This algorithm obtains N random lines from a file in one single pass.
 476                  * It does this by replacing elements of a fixed-size array of lines,
 477                  * less and less frequently as it reads the file.
 478                  */
 479                 $fh = fopen( $filepath, "r" );
 480                 if ( !$fh ) {
 481                         throw new Exception( "couldn't open $filepath" );
 482                 }
 483                 $line_number = 0;
 484                 $max_index = $number_desired - 1;
 485                 while ( !feof( $fh ) ) {
 486                         $line = fgets( $fh );
 487                         if ( $line !== false ) {
 488                                 $line_number++;
 489                                 $line = trim( $line );
 490                                 if ( mt_rand( 0, $line_number ) <= $max_index ) {
 491                                         $lines[mt_rand( 0, $max_index )] = $line;
 492                                 }
 493                         }
 494                 }
 495                 fclose( $fh );
 496                 if ( $line_number < $number_desired ) {
 497                         throw new Exception( "not enough lines in $filepath" );
 498                 }
 499
 500                 return $lines;
 501         }
 502 }