Recently in one of project I faced a requirement to display image in a developed paint tool of fixed dimensions canvas. It sounds fine as long as two points are not considered:
1. Image size can be anything because it is to be uploaded by user
2. Image should not crop and just fit in canvas without any scroll
There is function to resize image in PHP but available solutions somehow crop image to make best fit for canvas, which was not required. Finally this script helped us in scenario. I forgot ource of script so thought t shared on blog as well give credit to unknown developer : )
[code]
class ScaleImage
{
// ATTRIBUTES
var $image;
var $imageData = array();
var $lastError;
var $debugLevel; // 0 = no user_error, 1 = warning, 2 = error
// METHODS
/*
void ScaleImage([int debug_level])
constructor
*/
function ScaleImage($image, $maxWidth, $maxHeight, $debugLevel = 0)
{
$this->debugLevel = $debugLevel;
if($this->setImageData($image))
{
if($this->calcRatio($maxWidth, $maxHeight))
{
$this->displayImage();
}
}
} // end constructor
/*
bool setImageData(str image)
*/
function setImageData($image)
{
$result = TRUE;
if(is_readable($image))
{
$imageData = @getimagesize($image);
if($imageData == FALSE)
{
$this->error(“ScaleImage::setImageData(): not a valid image file”);
$result = FALSE;
}
else
{
$this->image = $image;
$this->imageData = $imageData;
}
}
else
{
$this->error(“ScaleImage::setImageData() – file not found”);
$result = FALSE;
}
return($result);
} // end setImageData
/*
bool calcRatio(int pixel_width, int pixel_height)
*/
function calcRatio($maxWidth, $maxHeight)
{
$result = TRUE;
if(is_numeric($maxWidth) and is_numeric($maxHeight))
{
$maxWidth = (INT) round($maxWidth);
$maxHeight = (INT) round($maxHeight);
if($maxWidth < 1 or $maxHeight < 1)
{
$this->error(“setMaxWidth(): max width or max height is < 1");
$result = FALSE;
}
else
{
if(!empty($this->imageData[0]) and !empty($this->imageData[1]))
{
$this->ratio = min($maxWidth / $this->imageData[0],
$maxHeight / $this->imageData[1],
1);
}
else
{
$this->error(“ScaleImage::calcRatio() – invalid source image size”);
$result = FALSE;
}
}
}
else
{
$this->error(“setMaxWidth(): max width or height is not numeric”);
$result = FALSE;
}
return($result);
} // end calcRatio()
/*
bool displayImage();
*/
function displayImage()
{
$result = TRUE;
$width = (INT) round($this->ratio * $this->imageData[0]);
$height = (INT) round($this->ratio * $this->imageData[1]);
if($width < 1 or $height < 1)
{
$this->error(“ScaleImage::displayImage() – new width or height < 1");
$result = FALSE;
}
else
{
$newImage = imagecreatetruecolor($width, $height);
switch($this->imageData[‘mime’])
{
case “image/jpeg”:
$oldImage = @imagecreatefromjpeg($this->image);
break;
case “image/png”:
$oldImage = @imagecreatefrompng($this->image);
break;
case “image/gif”:
$oldImage = @imagecreatefromgif($this->image);
break;
default:
$this->error(“ScaleImage::displayImage() – invalid mime type”);
$result = FALSE;
}
if($oldImage != FALSE)
{
if(imagecopyresampled($newImage, $oldImage, 0, 0, 0, 0, $width, $height,
$this->imageData[0], $this->imageData[1]))
{
header(“Content-Type: ” . $this->imageData[‘mime’]);
switch($this->imageData[‘mime’])
{
case “image/jpeg”:
imagejpeg($newImage, NULL, 100);
break;
case “image/png”:
imagejpeg($newImage, NULL, 100);
break;
case “image/gif”:
imagejpeg($newImage, NULL, 100);
break;
default:
$this->error(“ScaleImage::displayImage() – invalid mime type”);
$result = FALSE;
}
}
else
{
$this->error(“ScaleImage::displayImage() – copy failed”);
$result = FALSE;
}
}
else
{
$this->error(“ScaleImage::displayImage() – create new image failed”);
$result = FALSE;
}
}
} // end displayImage()
/*
void error(str error_message)
*/
function error($msg)
{
$this->lastError = $msg;
if($this->debugLevel)
{
$level = ($this->debugLevel == 2) ? E_USER_ERROR : E_USER_WARNING;
user_error($msg, $level);
}
} // end error()
} // end class ScaleImage
// SAMPLE USAGE:
$imageFile = ‘temp_file.jpg’;
$image = new ScaleImage($imageFile, 200, 200, 1);
[/code]
