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