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GUI CODE

Crop Canvas
By: Codewalkers
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    2003-08-01

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    This class allows you to crop an image in a variety of ways. You can crop in an absolute or relative way (to a certain size or by a certain size), both as a pixel number or a percentage. You can also save or display the cropped image. The cropping can be done in 9 different positions: top left, top, top right, left, centre, right, bottom left, bottom, or bottom right. Or you can automatically crop based on a threshold limit. The original image can be loaded from the file system or from a string (for example, data returned from a database.)

    The script attempts to auto-detect the GD version, so you should be able to use GD 1.6 and on up.

    By : amnuts


    <?php

    //
    // class.cropcanvas.php
    // version 1.2.0, 26th November, 2003
    //
    // Description
    //
    // This is a class allows you to crop an image in a variety of ways.
    // You can crop in an absolute or relative way (to a certain size or
    // by a certain size), both as a pixel number or a percentage. You
    // can also save or display the cropped image. The cropping can be
    // done in 9 different positions: top left, top, top right, left,
    // centre, right, bottom left, bottom, or bottom right. Or you can
    // crop automatically based on a threshold limit. The original
    // image can be loaded from the file system or from a string (for
    // example, data returned from a database.)
    //
    // Author
    //
    // Andrew Collington, 2003
    // php@amnuts.com, http://php.amnuts.com/
    //
    //
    // Feedback
    //
    // There is message board at the following address:
    //
    // http://php.amnuts.com/forums/index.php
    //
    // Please use that to post up any comments, questions, bug reports, etc. You
    // can also use the board to show off your use of the script.
    //
    // Support
    //
    // If you like this script, or any of my others, then please take a moment
    // to consider giving a donation. This will encourage me to make updates and
    // create new scripts which I would make available to you. If you would like
    // to donate anything, then there is a link from my website to PayPal.
    //
    // Example of use
    //
    // require 'class.cropcanvas.php';
    // $cc = new canvasCrop();
    //
    // $cc->loadImage('original1.png');
    // $cc->cropBySize(100, 100, ccBOTTOMRIGHT);
    // $cc->saveImage('final1.png');
    //
    // $cc->flushImages();
    //
    // $cc->loadImage('original2.png');
    // $cc->cropByPercent(15, 50, ccCENTER);
    // $cc->saveImage('final2.jpg', 90);
    //
    // $cc->flushImages();
    //
    // $cc->loadImage('original3.png');
    // $cc->cropToDimensions(67, 37, 420, 255);
    // $cc->showImage('png');
    //


    define("ccTOPLEFT", 0);
    define("ccTOP", 1);
    define("ccTOPRIGHT", 2);
    define("ccLEFT", 3);
    define("ccCENTRE", 4);
    define("ccCENTER", 4);
    define("ccRIGHT", 5);
    define("ccBOTTOMLEFT", 6);
    define("ccBOTTOM", 7);
    define("ccBOTTOMRIGHT", 8);


    class canvasCrop
    {
    var $_imgOrig;
    var $_imgFinal;
    var $_showDebug;
    var $_gdVersion;


    /**
    * @return canvasCrop
    * @param bool $debug
    * @desc Class initializer
    */
    function canvasCrop($debug = false)
    {
    $this->_showDebug = ($debug ? true : false);
    $this->_gdVersion = (function_exists('imagecreatetruecolor')) ? 2 : 1;
    }


    /**
    * @return bool
    * @param string $filename
    * @desc Load an image from the file system - method based on file extension
    */
    function loadImage($filename)
    {
    if (!@file_exists($filename))
    {
    $this->_debug('loadImage', "The supplied file name '$filename' does not point to a readable file.");
    return false;
    }

    $ext = strtolower($this->_getExtension($filename));
    $func = "imagecreatefrom$ext";

    if (!@function_exists($func))
    {
    $this->_debug('loadImage', "That file cannot be loaded with the function '$func'.");
    return false;
    }

    $this->_imgOrig = @$func($filename);

    if ($this->_imgOrig == null)
    {
    $this->_debug('loadImage', 'The image could not be loaded.');
    return false;
    }

    return true;
    }


    /**
    * @return bool
    * @param string $string
    * @desc Load an image from a string (eg. from a database table)
    */
    function loadImageFromString($string)
    {
    $this->_imgOrig = @ImageCreateFromString($string);
    if (!$this->_imgOrig)
    {
    $this->_debug('loadImageFromString', 'The image could not be loaded.');
    return false;
    }
    return true;
    }


    /**
    * @return bool
    * @param string $filename
    * @param int $quality
    * @desc Save the cropped image
    */
    function saveImage($filename, $quality = 100)
    {
    if ($this->_imgFinal == null)
    {
    $this->_debug('saveImage', 'There is no processed image to save.');
    return false;
    }

    $ext = strtolower($this->_getExtension($filename));
    $func = "image$ext";

    if (!@function_exists($func))
    {
    $this->_debug('saveImage', "That file cannot be saved with the function '$func'.");
    return false;
    }

    $saved = false;
    if ($ext == 'png') $saved = $func($this->_imgFinal, $filename);
    if ($ext == 'jpeg') $saved = $func($this->_imgFinal, $filename, $quality);
    if ($saved == false)
    {
    $this->_debug('saveImage', "Could not save the output file '$filename' as a $ext.");
    return false;
    }

    return true;
    }


    /**
    * @return bool
    * @param string $type
    * @param int $quality
    * @desc Shows the cropped image without any saving
    */
    function showImage($type = 'png', $quality = 100)
    {
    if ($this->_imgFinal == null)
    {
    $this->_debug('showImage', 'There is no processed image to show.');
    return false;
    }
    if ($type == 'png')
    {
    echo @ImagePNG($this->_imgFinal);
    return true;
    }
    else if ($type == 'jpg' || $type == 'jpeg')
    {
    echo @ImageJPEG($this->_imgFinal, '', $quality);
    return true;
    }
    else
    {
    $this->_debug('showImage', "Could not show the output file as a $type.");
    return false;
    }
    }


    /**
    * @return int
    * @param int $x
    * @param int $y
    * @param int $position
    * @desc Determines the dimensions to crop to if using the 'crop by size' method
    */
    function cropBySize($x, $y, $position = ccCENTRE)
    {
    if ($x == 0)
    {
    $nx = @ImageSX($this->_imgOrig);
    }
    else
    {
    $nx = @ImageSX($this->_imgOrig) - $x;
    }
    if ($y == 0)
    {
    $ny = @ImageSY($this->_imgOrig);
    }
    else
    {
    $ny = @ImageSY($this->_imgOrig) - $y;
    }
    return ($this->_cropSize(-1, -1, $nx, $ny, $position, 'cropBySize'));
    }


    /**
    * @return int
    * @param int $x
    * @param int $y
    * @param int $position
    * @desc Determines the dimensions to crop to if using the 'crop to size' method
    */
    function cropToSize($x, $y, $position = ccCENTRE)
    {
    if ($x == 0) $x = 1;
    if ($y == 0) $y = 1;
    return ($this->_cropSize(-1, -1, $x, $y, $position, 'cropToSize'));
    }


    /**
    * @return int
    * @param int $sx
    * @param int $sy
    * @param int $ex
    * @param int $ey
    * @desc Determines the dimensions to crop to if using the 'crop to dimensions' method
    */
    function cropToDimensions($sx, $sy, $ex, $ey)
    {
    $nx = abs($ex - $sx);
    $ny = abs($ey - $sy);
    return ($this->_cropSize($sx, $sy, $nx, $ny, $position, 'cropToDimensions'));
    }


    /**
    * @return int
    * @param int $percentx
    * @param int $percenty
    * @param int $position
    * @desc Determines the dimensions to crop to if using the 'crop by percentage' method
    */
    function cropByPercent($percentx, $percenty, $position = ccCENTRE)
    {
    if ($percentx == 0)
    {
    $nx = @ImageSX($this->_imgOrig);
    }
    else
    {
    $nx = @ImageSX($this->_imgOrig) - (($percentx / 100) * @ImageSX($this->_imgOrig));
    }
    if ($percenty == 0)
    {
    $ny = @ImageSY($this->_imgOrig);
    }
    else
    {
    $ny = @ImageSY($this->_imgOrig) - (($percenty / 100) * @ImageSY($this->_imgOrig));
    }
    return ($this->_cropSize(-1, -1, $nx, $ny, $position, 'cropByPercent'));
    }


    /**
    * @return int
    * @param int $percentx
    * @param int $percenty
    * @param int $position
    * @desc Determines the dimensions to crop to if using the 'crop to percentage' method
    */
    function cropToPercent($percentx, $percenty, $position = ccCENTRE)
    {
    if ($percentx == 0)
    {
    $nx = @ImageSX($this->_imgOrig);
    }
    else
    {
    $nx = ($percentx / 100) * @ImageSX($this->_imgOrig);
    }
    if ($percenty == 0)
    {
    $ny = @ImageSY($this->_imgOrig);
    }
    else
    {
    $ny = ($percenty / 100) * @ImageSY($this->_imgOrig);
    }
    return ($this->_cropSize(-1, -1, $nx, $ny, $position, 'cropByPercent'));
    }


    /**
    * @return bool
    * @param int $threshold
    * @desc Determines the dimensions to crop to if using the 'automatic crop by threshold' method
    */
    function cropByAuto($threshold = 254)
    {
    if ($threshold < 0) $threshold = 0;
    if ($threshold > 255) $threshold = 255;

    $sizex = @ImageSX($this->_imgOrig);
    $sizey = @ImageSY($this->_imgOrig);

    $sx = $sy = $ex = $ey = -1;
    for ($y = 0; $y < $sizey; $y++)
    {
    for ($x = 0; $x < $sizex; $x++)
    {
    if ($threshold >= $this->_getThresholdValue($this->_imgOrig, $x, $y))
    {
    if ($sy == -1) $sy = $y;
    else $ey = $y;

    if ($sx == -1) $sx = $x;
    else
    {
    if ($x < $sx) $sx = $x;
    else if ($x > $ex) $ex = $x;
    }
    }
    }
    }
    $nx = abs($ex - $sx);
    $ny = abs($ey - $sy);
    return ($this->_cropSize($sx, $sy, $nx, $ny, ccTOPLEFT, 'cropByAuto'));
    }


    /**
    * @return void
    * @desc Destroy the resources used by the images
    */
    function flushImages()
    {
    @ImageDestroy($this->_imgOrig);
    @ImageDestroy($this->_imgFinal);
    $this->_imgOrig = $this->_imgFinal = null;
    }


    /**
    * @return bool
    * @param int $ox Original image width
    * @param int $oy Original image height
    * @param int $nx New width
    * @param int $ny New height
    * @param int $position Where to place the crop
    * @param string $function Name of the calling function
    * @desc Creates the cropped image based on passed parameters
    */
    function _cropSize($ox, $oy, $nx, $ny, $position, $function)
    {
    if ($this->_imgOrig == null)
    {
    $this->_debug($function, 'The original image has not been loaded.');
    return false;
    }
    if (($nx <= 0) || ($ny <= 0))
    {
    $this->_debug($function, 'The image could not be cropped because the size given is not valid.');
    return false;
    }
    if (($nx > @ImageSX($this->_imgOrig)) || ($ny > @ImageSY($this->_imgOrig)))
    {
    $this->_debug($function, 'The image could not be cropped because the size given is larger than the original image.');
    return false;
    }
    if ($ox == -1 || $oy == -1)
    {
    list($ox, $oy) = $this->_getCopyPosition($nx, $ny, $position);
    }
    if ($this->_gdVersion == 2)
    {
    $this->_imgFinal = @ImageCreateTrueColor($nx, $ny);
    @ImageCopyResampled($this->_imgFinal, $this->_imgOrig, 0, 0, $ox, $oy, $nx, $ny, $nx, $ny);
    }
    else
    {
    $this->_imgFinal = @ImageCreate($nx, $ny);
    @ImageCopyResized($this->_imgFinal, $this->_imgOrig, 0, 0, $ox, $oy, $nx, $ny, $nx, $ny);
    }
    return true;
    }


    /**
    * @return array
    * @param int $nx
    * @param int $ny
    * @param int $position
    * @desc Determines dimensions of the crop
    */
    function _getCopyPosition($nx, $ny, $position)
    {
    $ox = @ImageSX($this->_imgOrig);
    $oy = @ImageSY($this->_imgOrig);

    switch($position)
    {
    case ccTOPLEFT:
    return array(0, 0);
    case ccTOP:
    return array(ceil(($ox - $nx) / 2), 0);
    case ccTOPRIGHT:
    return array(($ox - $nx), 0);
    case ccLEFT:
    return array(0, ceil(($oy - $ny) / 2));
    case ccCENTRE:
    return array(ceil(($ox - $nx) / 2), ceil(($oy - $ny) / 2));
    case ccRIGHT:
    return array(($ox - $nx), ceil(($oy - $ny) / 2));
    case ccBOTTOMLEFT:
    return array(0, ($oy - $ny));
    case ccBOTTOM:
    return array(ceil(($ox - $nx) / 2), ($oy - $ny));
    case ccBOTTOMRIGHT:
    return array(($ox - $nx), ($oy - $ny));
    }
    }


    /**
    * @return float
    * @param resource $im
    * @param int $x
    * @param int $y
    * @desc Determines the intensity value of a pixel at the passed co-ordinates
    */
    function _getThresholdValue($im, $x, $y)
    {
    $rgb = ImageColorAt($im, $x, $y);
    $r = ($rgb >> 16) & 0xFF;
    $g = ($rgb >> 8) & 0xFF;
    $b = $rgb & 0xFF;
    $intensity = ($r + $g + $b) / 3;
    return $intensity;
    }


    /**
    * @return string
    * @param string $filename
    * @desc Get the extension of a file name
    */
    function _getExtension($filename)
    {
    $ext = @strtolower(@substr($filename, (@strrpos($filename, ".") ? @strrpos($filename, ".") + 1 : @strlen($filename)), @strlen($filename)));
    return ($ext == 'jpg') ? 'jpeg' : $ext;
    }


    /**
    * @return void
    * @param string $function
    * @param string $string
    * @desc Shows debugging information
    */
    function _debug($function, $string)
    {
    if ($this->_showDebug)
    {
    echo "<p><strong style=\"color:#FF0000\">Error in function $function:</strong> $string</p>\n";
    }
    }


    /**
    * @return array
    * @desc Try to ascertain what the version of GD being used is, based on phpinfo output
    */
    function _getGDVersion()
    {
    static $version = array();

    if (empty($version))
    {
    ob_start();
    phpinfo();
    $buffer = ob_get_contents();
    ob_end_clean();
    if (preg_match("|<B>GD Version</B></td><TD ALIGN=\"left\">([^<]*)</td>|i", $buffer, $matches))
    {
    $version = explode('.', $matches[1]);
    }
    else if (preg_match("|GD Version </td><td class=\"v\">bundled \(([^ ]*)|i", $buffer, $matches))
    {
    $version = explode('.', $matches[1]);
    }
    else if (preg_match("|GD Version </td><td class=\"v\">([^ ]*)|i", $buffer, $matches))
    {
    $version = explode('.', $matches[1]);
    }
    }
    return $version;
    }

    }

    ?>
    DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware.

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