RandomImageGenerator.php

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<?php

class RandomImageGenerator {

    private $dictionaryFile;
    private $minWidth = 400;
    private $maxWidth = 800;
    private $minHeight = 400;
    private $maxHeight = 800;
    private $shapesToDraw = 5;

    private static $orientations = array(
        array(
            '0thRow' => 'top',
            '0thCol' => 'left',
            'exifCode' => 1,
            'counterRotation' => array( array( 1, 0 ), array( 0, 1 ) )
        ),
        array(
            '0thRow' => 'bottom',
            '0thCol' => 'right',
            'exifCode' => 3,
            'counterRotation' => array( array( -1, 0 ), array( 0, -1 ) )
        ),
        array(
            '0thRow' => 'right',
            '0thCol' => 'top',
            'exifCode' => 6,
            'counterRotation' => array( array( 0, 1 ), array( 1, 0 ) )
        ),
        array(
            '0thRow' => 'left',
            '0thCol' => 'bottom',
            'exifCode' => 8,
            'counterRotation' => array( array( 0, -1 ), array( -1, 0 ) )
        )
    );

    public function __construct( $options = array() ) {
        foreach ( array( 'dictionaryFile', 'minWidth', 'minHeight', 'maxWidth', 'maxHeight', 'shapesToDraw' ) as $property ) {
            if ( isset( $options[$property] ) ) {
                $this->$property = $options[$property];
            }
        }

        // find the dictionary file, to generate random names
        if ( !isset( $this->dictionaryFile ) ) {
            foreach (
                array(
                    '/usr/share/dict/words',
                    '/usr/dict/words',
                    __DIR__ . '/words.txt'
                ) as $dictionaryFile
            ) {
                if ( is_file( $dictionaryFile ) and is_readable( $dictionaryFile ) ) {
                    $this->dictionaryFile = $dictionaryFile;
                    break;
                }
            }
        }
        if ( !isset( $this->dictionaryFile ) ) {
            throw new Exception( "RandomImageGenerator: dictionary file not found or not specified properly" );
        }
    }

    function writeImages( $number, $format = 'jpg', $dir = null ) {
        $filenames = $this->getRandomFilenames( $number, $format, $dir );
        $imageWriteMethod = $this->getImageWriteMethod( $format );
        foreach ( $filenames as $filename ) {
            $this->{$imageWriteMethod}( $this->getImageSpec(), $format, $filename );
        }

        return $filenames;
    }

    function getImageWriteMethod( $format ) {
        global $wgUseImageMagick, $wgImageMagickConvertCommand;
        if ( $format === 'svg' ) {
            return 'writeSvg';
        } else {
            // figure out how to write images
            global $wgExiv2Command;
            if ( class_exists( 'Imagick' ) && $wgExiv2Command && is_executable( $wgExiv2Command ) ) {
                return 'writeImageWithApi';
            } elseif ( $wgUseImageMagick && $wgImageMagickConvertCommand && is_executable( $wgImageMagickConvertCommand ) ) {
                return 'writeImageWithCommandLine';
            }
        }
        throw new Exception( "RandomImageGenerator: could not find a suitable method to write images in '$format' format" );
    }

    private function getRandomFilenames( $number, $extension = 'jpg', $dir = null ) {
        if ( is_null( $dir ) ) {
            $dir = getcwd();
        }
        $filenames = array();
        foreach ( $this->getRandomWordPairs( $number ) as $pair ) {
            $basename = $pair[0] . '_' . $pair[1];
            if ( !is_null( $extension ) ) {
                $basename .= '.' . $extension;
            }
            $basename = preg_replace( '/\s+/', '', $basename );
            $filenames[] = "$dir/$basename";
        }

        return $filenames;
    }

    public function getImageSpec() {
        $spec = array();

        $spec['width'] = mt_rand( $this->minWidth, $this->maxWidth );
        $spec['height'] = mt_rand( $this->minHeight, $this->maxHeight );
        $spec['fill'] = $this->getRandomColor();

        $diagonalLength = sqrt( pow( $spec['width'], 2 ) + pow( $spec['height'], 2 ) );

        $draws = array();
        for ( $i = 0; $i <= $this->shapesToDraw; $i++ ) {
            $radius = mt_rand( 0, $diagonalLength / 4 );
            if ( $radius == 0 ) {
                continue;
            }
            $originX = mt_rand( -1 * $radius, $spec['width'] + $radius );
            $originY = mt_rand( -1 * $radius, $spec['height'] + $radius );
            $angle = mt_rand( 0, ( 3.141592 / 2 ) * $radius ) / $radius;
            $legDeltaX = round( $radius * sin( $angle ) );
            $legDeltaY = round( $radius * cos( $angle ) );

            $draw = array();
            $draw['fill'] = $this->getRandomColor();
            $draw['shape'] = array(
                array( 'x' => $originX, 'y' => $originY - $radius ),
                array( 'x' => $originX + $legDeltaX, 'y' => $originY + $legDeltaY ),
                array( 'x' => $originX - $legDeltaX, 'y' => $originY + $legDeltaY ),
                array( 'x' => $originX, 'y' => $originY - $radius )
            );
            $draws[] = $draw;
        }

        $spec['draws'] = $draws;

        return $spec;
    }

    static function shapePointsToString( $shape ) {
        $points = array();
        foreach ( $shape as $point ) {
            $points[] = $point['x'] . ',' . $point['y'];
        }

        return join( " ", $points );
    }

    public function writeSvg( $spec, $format, $filename ) {
        $svg = new SimpleXmlElement( '<svg/>' );
        $svg->addAttribute( 'xmlns', 'http://www.w3.org/2000/svg' );
        $svg->addAttribute( 'version', '1.1' );
        $svg->addAttribute( 'width', $spec['width'] );
        $svg->addAttribute( 'height', $spec['height'] );
        $g = $svg->addChild( 'g' );
        foreach ( $spec['draws'] as $drawSpec ) {
            $shape = $g->addChild( 'polygon' );
            $shape->addAttribute( 'fill', $drawSpec['fill'] );
            $shape->addAttribute( 'points', self::shapePointsToString( $drawSpec['shape'] ) );
        }

        if ( !$fh = fopen( $filename, 'w' ) ) {
            throw new Exception( "couldn't open $filename for writing" );
        }
        fwrite( $fh, $svg->asXML() );
        if ( !fclose( $fh ) ) {
            throw new Exception( "couldn't close $filename" );
        }
    }

    public function writeImageWithApi( $spec, $format, $filename ) {
        // this is a hack because I can't get setImageOrientation() to work. See below.
        global $wgExiv2Command;

        $image = new Imagick();
        $orientation = self::$orientations[0]; // default is normal orientation
        if ( $format == 'jpg' ) {
            $orientation = self::$orientations[array_rand( self::$orientations )];
            $spec = self::rotateImageSpec( $spec, $orientation['counterRotation'] );
        }

        $image->newImage( $spec['width'], $spec['height'], new ImagickPixel( $spec['fill'] ) );

        foreach ( $spec['draws'] as $drawSpec ) {
            $draw = new ImagickDraw();
            $draw->setFillColor( $drawSpec['fill'] );
            $draw->polygon( $drawSpec['shape'] );
            $image->drawImage( $draw );
        }

        $image->setImageFormat( $format );

        // this doesn't work, even though it's documented to do so...
        // $image->setImageOrientation( $orientation['exifCode'] );

        $image->writeImage( $filename );

        // because the above setImageOrientation call doesn't work... nor can I get an external imagemagick binary to do this either...
        // hacking this for now (only works if you have exiv2 installed, a program to read and manipulate exif)
        if ( $wgExiv2Command ) {
            $cmd = wfEscapeShellArg( $wgExiv2Command )
                . " -M "
                . wfEscapeShellArg( "set Exif.Image.Orientation " . $orientation['exifCode'] )
                . " "
                . wfEscapeShellArg( $filename );

            $retval = 0;
            $err = wfShellExec( $cmd, $retval );
            if ( $retval !== 0 ) {
                print "Error with $cmd: $retval, $err\n";
            }
        }
    }

    private static function rotateImageSpec( &$spec, $matrix ) {
        $tSpec = array();
        $dims = self::matrixMultiply2x2( $matrix, $spec['width'], $spec['height'] );
        $correctionX = 0;
        $correctionY = 0;
        if ( $dims['x'] < 0 ) {
            $correctionX = abs( $dims['x'] );
        }
        if ( $dims['y'] < 0 ) {
            $correctionY = abs( $dims['y'] );
        }
        $tSpec['width'] = abs( $dims['x'] );
        $tSpec['height'] = abs( $dims['y'] );
        $tSpec['fill'] = $spec['fill'];
        $tSpec['draws'] = array();
        foreach ( $spec['draws'] as $draw ) {
            $tDraw = array(
                'fill' => $draw['fill'],
                'shape' => array()
            );
            foreach ( $draw['shape'] as $point ) {
                $tPoint = self::matrixMultiply2x2( $matrix, $point['x'], $point['y'] );
                $tPoint['x'] += $correctionX;
                $tPoint['y'] += $correctionY;
                $tDraw['shape'][] = $tPoint;
            }
            $tSpec['draws'][] = $tDraw;
        }

        return $tSpec;
    }

    private static function matrixMultiply2x2( $matrix, $x, $y ) {
        return array(
            'x' => $x * $matrix[0][0] + $y * $matrix[0][1],
            'y' => $x * $matrix[1][0] + $y * $matrix[1][1]
        );
    }

    public function writeImageWithCommandLine( $spec, $format, $filename ) {
        global $wgImageMagickConvertCommand;
        $args = array();
        $args[] = "-size " . wfEscapeShellArg( $spec['width'] . 'x' . $spec['height'] );
        $args[] = wfEscapeShellArg( "xc:" . $spec['fill'] );
        foreach ( $spec['draws'] as $draw ) {
            $fill = $draw['fill'];
            $polygon = self::shapePointsToString( $draw['shape'] );
            $drawCommand = "fill $fill  polygon $polygon";
            $args[] = '-draw ' . wfEscapeShellArg( $drawCommand );
        }
        $args[] = wfEscapeShellArg( $filename );

        $command = wfEscapeShellArg( $wgImageMagickConvertCommand ) . " " . implode( " ", $args );
        $retval = null;
        wfShellExec( $command, $retval );

        return ( $retval === 0 );
    }

    public function getRandomColor() {
        $components = array();
        for ( $i = 0; $i <= 2; $i++ ) {
            $components[] = mt_rand( 0, 255 );
        }

        return 'rgb(' . join( ', ', $components ) . ')';
    }

    private function getRandomWordPairs( $number ) {
        $lines = $this->getRandomLines( $number * 2 );
        // construct pairs of words
        $pairs = array();
        $count = count( $lines );
        for ( $i = 0; $i < $count; $i += 2 ) {
            $pairs[] = array( $lines[$i], $lines[$i + 1] );
        }

        return $pairs;
    }

    private function getRandomLines( $number_desired ) {
        $filepath = $this->dictionaryFile;

        // initialize array of lines
        $lines = array();
        for ( $i = 0; $i < $number_desired; $i++ ) {
            $lines[] = null;
        }

        /*
         * This algorithm obtains N random lines from a file in one single pass. It does this by replacing elements of
         * a fixed-size array of lines, less and less frequently as it reads the file.
         */
        $fh = fopen( $filepath, "r" );
        if ( !$fh ) {
            throw new Exception( "couldn't open $filepath" );
        }
        $line_number = 0;
        $max_index = $number_desired - 1;
        while ( !feof( $fh ) ) {
            $line = fgets( $fh );
            if ( $line !== false ) {
                $line_number++;
                $line = trim( $line );
                if ( mt_rand( 0, $line_number ) <= $max_index ) {
                    $lines[mt_rand( 0, $max_index )] = $line;
                }
            }
        }
        fclose( $fh );
        if ( $line_number < $number_desired ) {
            throw new Exception( "not enough lines in $filepath" );
        }

        return $lines;
    }
}