/imageserver.php

<?php
include 'imageserver.config.php';

if (URI_PROTOCOL == 'REQUEST_URI')
{
	$filename = $_SERVER['REQUEST_URI'];

	if (isset($_SERVER['QUERY_STRING']))
	{
		$filename = str_replace("?$_SERVER[QUERY_STRING]", '', $filename);
	}
}
else
{
	$filename = isset($_SERVER['REDIRECT_URL']) ? $_SERVER['REDIRECT_URL'] : NULL;
}

if ( ! $filename)
{
	exit;
}

$filename = DIR_RELATIVE . str_replace(SCRIPT_RELATIVE .'imgs/', '', $filename);

$filename = urldecode($filename);

if ( ! file_exists($filename))
{
	//The source image can't be found, so use a default, if it is set
	if (defined('REPLACEMENT_IMG') AND file_exists(DIR_RELATIVE.REPLACEMENT_IMG))
	{
		$location = "http://$_SERVER[HTTP_HOST]". SCRIPT_RELATIVE .'imgs/'. REPLACEMENT_IMG;
		
		if ($_SERVER['QUERY_STRING'])
		{
			$location .= "?$_SERVER[QUERY_STRING]";
		}
		
		imgs_log("File $filename not found, 301 redirect to: $location");
		
		header("Location: $location", TRUE, 307);
	}
	else
	{
		imgs_log("File '$filename' not found");
	}
	
	exit;
}

if (CACHE_EXPIRES)
{
	$exp_time = strtotime(CACHE_EXPIRES);
	header('Expires: ' . date(DATE_RFC2822, $exp_time));
	header('Pragma: cache');
	$seconds = $exp_time - time();
	header("Cache-Control: public, max-age=$seconds, pre-check=$seconds");
}

list($orig_width, $orig_height, $type) = getimagesize($filename);
$width = 0;
$height = 0;

/*
 * Fetch user defined parameters
 */
if (isset($_GET['w']) AND is_numeric($_GET['w']))
{
	$width = intval($_GET['w']);
}

if (isset($_GET['h']) AND is_numeric($_GET['h']))
{
	$height = intval($_GET['h']);
}

$should_watermark = FALSE;

// If resizing was not requested, but the image is larger than the minimum for watermarking
if (WATERMARK AND ! $width AND ! $height AND ($orig_width >= WATERMARK_MINW OR $orig_height >= WATERMARK_MINH))
{
	$width = $orig_width;
	$height = $orig_height;
	$should_watermark = TRUE;
}
elseif (WATERMARK AND (($width > WATERMARK_MINW OR $height > WATERMARK_MINH)))
{
	$should_watermark = TRUE;
}

// If the requested file is the original, non-processed image
if ( ! $width AND  ! $height AND ! $should_watermark)
{
	// If the file exists, just serve it and finish execution
	$details = getimagesize($filename);

	if ($details)
	{
		header('Content-Type: '. $details['mime']);

		echo file_get_contents($filename);

		exit();
	}
}

$should_fill = FALSE;
$should_cut = FALSE;

// If we have both width and height requested, we can fill or cut
if ($width AND $height)
{
	if ((isset($_GET['f']) AND $_GET['f'] == 1) OR BG_FILL)
	{
		$should_fill = TRUE;
	}
	else
	{
		// Should we cut the image to fill the requested dimensions?
		// -------------------------------------------------------------------------
		if (isset($_GET['c']))
		{
			if ($_GET['c'] == 1)
			{
				$should_cut = TRUE;
			}
		}
		elseif (CUTTING)
		{
			$should_cut = TRUE;
		}
	}
}

$pi = pathinfo($filename);

$target_dir = CACHE_RELATIVE."/{$pi['dirname']}";

$bg_tag = ($should_fill ? '_bg' : '');

$wm_tag = ($should_watermark ? '_wm' : '');

$ct_tag = ($should_cut ? '_c' : '');

// Target file is a resized image
$target_file = "{$target_dir}/{$pi['filename']}_{$width}_{$height}{$bg_tag}{$wm_tag}{$ct_tag}.{$pi['extension']}";

// Has this request already been cached once upon a time?
if (CACHE AND file_exists($target_file) AND (filectime($target_file) > filectime($filename)))
{
	imgs_log("Serving from cache");

	$details = getimagesize($target_file);

	if ($details)
	{
		header('Content-Type: '. $details['mime']);

		echo file_get_contents($target_file);

		exit();
	}
}
else
{
	// Original file exists and resize/resample action is needed

	// Does the target directory exist?
	if (CACHE AND ! is_dir($target_dir) AND ! mkdir($target_dir, 0775, TRUE))
	{
		// Directory not found and we were unable to create one...
		// TODO: handle target directory creation error
		exit();
	}

	$ratio = $orig_width/$orig_height;

	// If one of the dimensions was not specified, use the original scaled by the difference ratio
	// If cutting, this will have no effect (cutting requires both dimensions, so neither of these eval as TRUE)
	if ($width == 0)
	{
		$width = round($orig_width * ($height/$orig_height));
	}
	elseif ($height == 0)
	{
		$height = round($orig_height * ($width/$orig_width));
	}

	$resample_width = $width;
	$resample_height = $height;

	// Preserve aspect ratio
	if ($resample_width / $resample_height > $ratio)
	{
		$resample_width = round($resample_height * $ratio);
	}
	else
	{
		$resample_height = round($resample_width / $ratio);
	}

	$dst_x = 0;
	$dst_y = 0;
	$src_x = 0;
	$src_y = 0;

	if ($should_fill AND strlen(BG_RGB) == 7)
	{
		// If background filling is enabled, create an image with the requested dimension
		$new_image = imagecreatetruecolor($width, $height);

		// Fill the image with the specified colour
		$bg = sscanf(BG_RGB, '#%2x%2x%2x');
		$new_image_bg = imagecolorallocate($new_image, $bg[0], $bg[1], $bg[2]);
		imagefill($new_image, 0, 0, $new_image_bg);

		if ($width == $resample_width)
		{
			$dst_x = 0;
		}
		elseif ($width > $resample_width)
		{
			$dst_x = round(($width - $resample_width) / 2);
		}
		else
		{
			$dst_x = round(($resample_width - $width) / 2);
		}

		if ($height == $resample_height)
		{
			$dst_y = 0;
		}
		elseif ($height > $resample_height)
		{
			$dst_y = round(($height - $resample_height) / 2);
		}
		else
		{
			$dst_y = round(($resample_height - $height) / 2);
		}
	}
	elseif ($should_cut)
	{
		// Will cut, so the requested dimension will be respected
		$new_image = imagecreatetruecolor($width, $height);
		$target_ar = round($width/$height, 2);
		$ratio = round($ratio, 2);

		if ($orig_width == $orig_height) // ------------------------------------ Source is square
		{
			if ($width < $height)
			{
				// Target is portrait
				$resample_height = $height;
				$resample_width = round($resample_height * $ratio);

				$dst_x = - ceil(($resample_width - $width) / 2);
			}
			elseif ($width > $height)
			{
				// Target is landscape
				$resample_width = $width;
				$resample_height = round($resample_width / $ratio);

				$dst_y = - ceil(($resample_height - $height) / 2);
			}
		}
		elseif ($orig_width < $orig_height)	// --------------------------------- Source is portrait
		{
			if ($width >= $height OR $target_ar > $ratio)
			{
				// Target is square or landscape or less narrow than the original
				$resample_width = $width;
				$resample_height = round($resample_width / $ratio);

				$dst_y = - ceil(($resample_height - $height) / 2);
			}
			elseif ($width < $height AND $target_ar < $ratio)
			{
				// Target is portrait or more narrow than the original
				$resample_height = $height;
				$resample_width = round($resample_height * $ratio);

				$dst_x = - ceil(($resample_width - $width) / 2);
			}
		}
		else // ---------------------------------------------------------------- Source is landscape
		{
			if ($width <= $height OR $target_ar < $ratio)
			{
				// Target is square or portrait or more narrow than the original
				$resample_height = $height;
				$resample_width = round($resample_height * $ratio);

				$dst_x = - ceil(($resample_width - $width) / 2);
			}
			elseif ($target_ar > $ratio)
			{
				// Target is landscape or less narrow than the original
				$resample_width = $width;
				$resample_height = round($resample_width / $ratio);

				$dst_y = - ceil(($resample_height - $height) / 2);
			}
		}
	}
	else
	{
		// No background filling or cutting, create an image with same ratio
		$new_image = imagecreatetruecolor($resample_width, $resample_height);
	}

	// Retain transparency, if any
	if ( ! $should_fill)
	{
		$trans_colour = imagecolorallocatealpha($new_image, 0, 0, 0, 127);
		imagefill($new_image, 0, 0, $trans_colour);
		imagesavealpha($new_image, TRUE);
	}

	// TODO: set padding if required

	imgs_log("imagecopyresampled($target_file, $filename, $dst_x, $dst_y, $src_x, $src_y, $resample_width, $resample_height, $orig_width, $orig_height)");

	switch ($type)
	{
		// ----
		case 1: // GIF
		// ----

			$image = imagecreatefromgif($filename);

			if ($image)
			{
				if (imagecopyresampled($new_image, $image, $dst_x, $dst_y, $src_x, $src_y, $resample_width, $resample_height, $orig_width, $orig_height))
				{
					if ($should_watermark)
					{
						imgs_apply_watermark($new_image);
					}
					
					// Save to cache
					if (CACHE)
					{
						imagegif($new_image, $target_file);
						//@chmod($target_file,PERMISSION);
					}

					// Output
					header('Content-type: image/gif');
					imagegif($new_image);
				}
			}
			
			break;

		// ----
		case 2: //JPEG
		// ----

			$image = imagecreatefromjpeg($filename);

			if ($image)
			{
				if (imagecopyresampled($new_image, $image, $dst_x, $dst_y, $src_x, $src_y, $resample_width, $resample_height, $orig_width, $orig_height))
				{
					if ($should_watermark)
					{
						imgs_apply_watermark($new_image);
					}

					// Save to cache
					if (CACHE)
					{
						imagejpeg($new_image, $target_file, JPEG_QUALITY);
						//@chmod($target_file,PERMISSION);
					}					

					// Output
					header('Content-type: image/jpeg');
					imagejpeg($new_image, NULL, JPEG_QUALITY);
				}
			}
			
			break;

		// ----
		case 3: // PNG
		// ----
			
			$line = "Creating PNG: ";
			$image = imagecreatefrompng($filename);
			
			if ($image)
			{
				$line .= "OK";
				imgs_log($line);

				$line = "Resampling: ";

				if (imagecopyresampled($new_image, $image, $dst_x, $dst_y, $src_x, $src_y, $resample_width, $resample_height, $orig_width, $orig_height))
				{
					$line .= "OK";
					
					if ($should_watermark)
					{
						imgs_apply_watermark($new_image);
					}
					
					// Save to cache
					if (CACHE)
					{
						imagepng($new_image, $target_file, PNG_QUALITY);
						//@chmod($target_file,PERMISSION);
					}
					
					// Output
					header('Content-type: image/png');
					imagepng($new_image, NULL, PNG_QUALITY);
				}
				else
				{
					$line .= "FAILED";
				}
			}
			else
			{
				$line .= "FAILED";
			}

			imgs_log($line);

	} // -- end type switch
}

function imgs_log($line)
{
	if ( ! DEBUG)
	{
		return;
	}

    if ( ! file_exists(LOG_PATH) OR ! is_writeable(LOG_PATH))
	{
        return;
    }

	$line = date("Y-m-d H:i:s") .": $line\n";

	file_put_contents(LOG_PATH, $line, FILE_APPEND | LOCK_EX);
}

/**
 * Apply the watermark to the image
 * @param resource $image
 * @param int $width
 * @param int $height
 * @return bool
 */
function imgs_apply_watermark(&$image)
{
	if (file_exists(WATERMARK))
	{
		$wm = imagecreatefrompng(WATERMARK);

		list($wm_width, $wm_height) = getimagesize(WATERMARK);

		$width = imagesx($image);
		$height = imagesy($image);

		// If we want resizing or the watermark is too big for this image
		if (WATERMARK_RESIZE OR $wm_width > $width OR $wm_height > $height)
		{
			$ratio = $wm_width/$wm_height;

			$new_wm_height = $height;
			$new_wm_width = $width;

			// Preserve aspect ratio of the watermark
			if ($new_wm_width/$new_wm_height > $ratio)
			{
				$new_wm_width = round($new_wm_height*$ratio);
			}
			else
			{
				$new_wm_height = round($new_wm_width/$ratio);
			}
		}
		else
		{
			$new_wm_height = $wm_height;
			$new_wm_width = $wm_width;
		}

		switch (WATERMARK_HALIGN)
		{
			case 'left':	$dst_x = 0; break;
			case 'right':	$dst_x = $width - $new_wm_width; break;
			default:
			case 'center':	$dst_x = intval(($width - $new_wm_width) / 2);
		}

		switch (WATERMARK_VALIGN)
		{
			case 'top':		$dst_y = 0; break;
			case 'bottom':	$dst_y = $height - $new_wm_height; break;
			default:
			case 'center':	$dst_y = intval(($height - $new_wm_height) / 2);
		}

		// Copy resampled watermark
		imagecopyresampled($image, $wm, $dst_x, $dst_y, 0, 0, $new_wm_width, $new_wm_height, $wm_width, $wm_height);

		return TRUE;
	}

	return FALSE;
}