<?php
/**
* Class: ThumbnailFile
* Creates and serves compressed image thumbnails.
*/
class ThumbnailFile {
# Integer: $orig_w
# Width of the original image.
private $orig_w = 0;
# Integer: $orig_h
# Height of the original image.
private $orig_h = 0;
# Integer: $thumb_w
# Width calculated for the thumbnail.
private $thumb_w = 1;
# Integer: $thumb_h
# Height calculated for the thumbnail.
private $thumb_h = 1;
# Integer: $crop_x
# Horizontal offset in pixels for cropping.
private $crop_x = 0;
# Integer: $crop_y
# Vertical offset in pixels for cropping.
private $crop_y = 0;
# Integer: $quality
# Quality factor for the thumbnail file.
private $quality = 80;
# Integer: $orientation
# EXIF orientation tag value.
private $orientation = 1;
# Variable: $type
# The original image type detected by GD library.
private $type = 0;
# Boolean: $square
# Square thumbnail image requested?
private $square = false;
# String: $source
# The source filepath supplied to the constructor.
private $source = null;
# String: $name
# The unique destination name generated from parameters.
private $name = null;
# String: $destination
# The destination filepath.
private $destination = null;
# Boolean: $creatable
# Can a thumbnail be created?
private $creatable = null;
/**
* Function: __construct
* Receives the source filename and requested thumbnail parameters.
*
* Parameters:
* $filename - Filename relative to the uploads directory.
* $thumb_w - Requested thumbnail width (0 = auto).
* $thumb_h - Requested thumbnail height (0 = auto).
* $quality - Quality factor for the thumbnail file.
* $square - Create a square crop of the original image?
*/
public function __construct(
$filename,
$thumb_w,
$thumb_h,
$quality,
$square
) {
$this->thumb_w = (int) $thumb_w;
$this->thumb_h = (int) $thumb_h;
$this->quality = (int) $quality;
$this->square = (bool) $square;
$filepath = uploaded($filename, false);
$image_info = @getimagesize($filepath);
if ($image_info === false)
return;
$this->source = $filepath;
$this->type = $image_info[2];
if ($image_info[0] != 0)
$this->orig_w = $image_info[0];
if ($image_info[1] != 0)
$this->orig_h = $image_info[1];
if ($this->thumb_w == 0 and $this->thumb_h == 0) {
$this->thumb_w = 1;
$this->thumb_h = 1;
}
if ($this->quality > 100 or $this->quality < 0)
$this->quality = 80;
if (function_exists("exif_read_data")) {
$exif = @exif_read_data($filepath);
if ($exif !== false) {
if (isset($exif["Orientation"]))
$this->orientation = (int) $exif["Orientation"];
if ($this->orientation >= 5) {
$orig_w = $this->orig_w;
$orig_h = $this->orig_h;
$this->orig_w = $orig_h;
$this->orig_h = $orig_w;
}
}
}
$this->resize();
$this->destination = CACHES_DIR.DIR."thumbs".DIR.$this->name();
}
/**
* Function: upscaling
* Will the thumbnail be larger than the original?
*/
public function upscaling(
): bool {
return (
($this->thumb_w == 0 or $this->orig_w <= $this->thumb_w) and
($this->thumb_h == 0 or $this->orig_h <= $this->thumb_h) and
(!$this->square or $this->orig_w == $this->orig_h)
);
}
/**
* Function: creatable
* Can the thumbnail file be created?
*/
public function creatable(
): bool {
if (isset($this->creatable))
return $this->creatable;
if (!isset($this->source))
return $this->creatable = false;
if (!function_exists("gd_info"))
return $this->creatable = false;
$imagetypes = imagetypes();
if ($this->type == IMAGETYPE_GIF and ($imagetypes & IMG_GIF)) {
# If a square crop is requested, animation is irrelevant.
if ($this->square)
return $this->creatable = true;
# Probe the file and return false if GIF89a with animation
# because GD will only operate on the first frame of the file.
$data = @fopen(filename:$this->source, mode:"rb");
if ($data === false)
return $this->creatable = false;
$count = 0;
$contents = "";
# Count the number of graphic control extension blocks
# followed by an image descriptor or another extension:
# > Graphic Control Extension
# > Extension Introducer (0x21)
# > Graphic Control Label (0xf9)
# > Block Size (0x04)
# > <Packed Fields> (1 byte)
# > Delay Time (2 bytes)
# > Transparent Color Index (1 byte)
# > Block Terminator (0x00)
# > Image Descriptor / Graphic Control Extension
# > Extension Introducer (0x2c / 0x21)
#
# See also:
# https://www.w3.org/Graphics/GIF/spec-gif89a.txt
#
while (!feof($data) and $count < 2) {
$contents.= fread($data, 102400);
$count = (int) preg_match_all(
"/\\x21\\xf9\\x04.{4}\\x00(\\x2c|\\x21)/s",
$contents
);
}
return $this->creatable = ($count < 2) ?
true :
false ;
}
if ($this->type == IMAGETYPE_JPEG and ($imagetypes & IMG_JPEG))
return $this->creatable = true;
if ($this->type == IMAGETYPE_PNG and ($imagetypes & IMG_PNG))
return $this->creatable = true;
if ($this->type == IMAGETYPE_WEBP and ($imagetypes & IMG_WEBP)) {
# Probe the file and return false if WEBP VP8X with animation
# because GD will throw a PHP Fatal error on imagecreatefromwebp().
$data = @file_get_contents(filename:$this->source, length:21);
if ($data === false or strlen($data) < 21)
return $this->creatable = false;
# Unpack the following data from the first 21 bytes of the WEBP file:
# > File header (12 bytes)
# > First chunk:
# > Chunk header (4 bytes)
# > Chunk size (4 bytes)
# > Chunk payload (1 byte only)
#
# See also:
# https://developers.google.com/speed/webp/docs/riff_container
#
$header = unpack(
"A4riff/Vfilesize/A4webp/A4header/Vsize/Cpayload",
$data
);
# Discover if VP8X header is present and animation bit is set.
if ($header['header'] == "VP8X" and $header['payload'] & 0x02)
return $this->creatable = false;
return $this->creatable = true;
}
if (!defined('IMAGETYPE_AVIF'))
return $this->creatable = false;
if (!defined('IMG_AVIF'))
return $this->creatable = false;
if ($this->type == IMAGETYPE_AVIF and ($imagetypes & IMG_AVIF))
return $this->creatable = true;
return $this->creatable = false;
}
/**
* Function: extension
* Returns the correct extension for the image.
*/
public function extension(
): string|false {
return image_type_to_extension($this->type);
}
/**
* Function: mime_type
* Returns the correct MIME type for the image.
*/
public function mime_type(
): string|false {
return image_type_to_mime_type($this->type);
}
/**
* Function: name
* Generates and returns a unique name for the thumbnail file.
*/
public function name(
): string|false {
if (isset($this->name))
return $this->name;
if (!isset($this->source))
return false;
$hash = md5(
basename($this->source).
$this->thumb_w.
$this->thumb_h.
$this->quality
);
return $this->name = $hash.$this->extension();
}
/**
* Function: create
* Creates a thumbnail file using the supplied parameters.
*
* Parameters:
* $overwrite - Overwrite an existing thumbnail file?
*/
public function create(
$overwrite = false
): bool {
if (!$this->creatable())
return false;
# Check if a fresh image thumbnail already exists.
if (
!$overwrite and
file_exists($this->destination) and
filemtime($this->destination) >= filemtime($this->source)
) {
if (DEBUG)
error_log("IMAGE fresh ".$this->destination);
return true;
}
$thumb = imagecreatetruecolor($this->thumb_w, $this->thumb_h);
if ($thumb === false)
error(
__("Error"),
__("Failed to create image thumbnail.")
);
switch ($this->type) {
case IMAGETYPE_GIF:
$original = @imagecreatefromgif($this->source);
break;
case IMAGETYPE_JPEG:
$original = @imagecreatefromjpeg($this->source);
imageinterlace($thumb, true);
break;
case IMAGETYPE_PNG:
$original = @imagecreatefrompng($this->source);
imagealphablending($thumb, false);
imagesavealpha($thumb, true);
break;
case IMAGETYPE_WEBP:
$original = @imagecreatefromwebp($this->source);
imagealphablending($thumb, false);
imagesavealpha($thumb, true);
break;
case IMAGETYPE_AVIF:
$original = @imagecreatefromavif($this->source);
imagealphablending($thumb, false);
imagesavealpha($thumb, true);
break;
}
if ($original === false)
error(
__("Error"),
__("Failed to create image thumbnail.")
);
if ($this->orientation > 1) {
# Transform the original image to correct orientation:
#####################################################
# 1 # 2 # 3 # 4 #
# # # # #
# XXXXXXX # XXXXXXX # XX # XX #
# XX # XX # XX # XX #
# XXXXX # XXXXX # XXXXX # XXXXX #
# XX # XX # XX # XX #
# XX # XX # XXXXXXX # XXXXXXX #
# # # # #
#####################################################
# 5 # 6 # 7 # 8 #
# # # # #
# XXXXXXXXXX # # # XXXXXXXXXX #
# XX XX # XX # XX # XX XX #
# XX XX # XX XX # XX XX # XX XX #
# XX # XX XX # XX XX # XX #
# # XXXXXXXXXX # XXXXXXXXXX # #
# # # # #
#####################################################
switch ($this->orientation) {
case 2:
imageflip($original, IMG_FLIP_HORIZONTAL);
break;
case 3:
$original = imagerotate($original, 180, 0);
break;
case 4:
imageflip($original, IMG_FLIP_VERTICAL);
break;
case 5:
imageflip($original, IMG_FLIP_VERTICAL);
$original = imagerotate($original, 270, 0);
break;
case 6:
$original = imagerotate($original, 270, 0);
break;
case 7:
imageflip($original, IMG_FLIP_VERTICAL);
$original = imagerotate($original, 90, 0);
break;
case 8:
$original = imagerotate($original, 90, 0);
break;
}
if ($original === false)
error(
__("Error"),
__("Failed to create image thumbnail.")
);
}
# Do the crop and resize.
imagecopyresampled(
$thumb,
$original,
0,
0,
$this->crop_x,
$this->crop_y,
$this->thumb_w,
$this->thumb_h,
$this->orig_w,
$this->orig_h
);
# Create the thumbnail file.
switch ($this->type) {
case IMAGETYPE_GIF:
$result = imagegif(
$thumb,
$this->destination
);
break;
case IMAGETYPE_JPEG:
$result = imagejpeg(
$thumb,
$this->destination,
$this->quality
);
break;
case IMAGETYPE_PNG:
$result = imagepng(
$thumb,
$this->destination
);
break;
case IMAGETYPE_WEBP:
$result = imagewebp(
$thumb,
$this->destination,
$this->quality
);
break;
case IMAGETYPE_AVIF:
$result = imageavif(
$thumb,
$this->destination,
$this->quality
);
break;
}
imagedestroy($thumb);
imagedestroy($original);
if ($result === false)
error(
__("Error"),
__("Failed to create image thumbnail.")
);
if (DEBUG)
error_log("IMAGE created ".$this->destination);
return true;
}
/**
* Function: serve
* Serves a thumbnail file with correct Content-Type header.
*/
public function serve(
): bool {
if (!file_exists($this->destination))
return false;
header("Content-Type: ".$this->mime_type());
readfile($this->destination);
if (DEBUG)
error_log("IMAGE served ".$this->destination);
return true;
}
/**
* Function: resize
* Computes the final dimensions based on supplied parameters.
*/
private function resize(
): void {
$scale_x = ($this->thumb_w > 0) ?
$this->thumb_w / $this->orig_w :
0 ;
$scale_y = ($this->thumb_h > 0) ?
$this->thumb_h / $this->orig_h :
0 ;
if ($this->square) {
if ($this->thumb_w > $this->thumb_h)
$this->thumb_h = $this->thumb_w;
if ($this->thumb_h > $this->thumb_w)
$this->thumb_w = $this->thumb_h;
# Portrait orientation.
if ($this->orig_w > $this->orig_h) {
$this->crop_x = round(
($this->orig_w - $this->orig_h) / 2
);
$this->orig_w = $this->orig_h;
}
# Landscape orientation.
if ($this->orig_h > $this->orig_w) {
$this->crop_y = round(
($this->orig_h - $this->orig_w) / 2
);
$this->orig_h = $this->orig_w;
}
return;
}
if ($this->thumb_h == 0) {
$this->thumb_h = round(
($this->thumb_w / $this->orig_w) * $this->orig_h
);
return;
}
if ($this->thumb_w == 0) {
$this->thumb_w = round(
($this->thumb_h / $this->orig_h) * $this->orig_w
);
return;
}
# Recompute to retain aspect ratio and stay within bounds.
if ($scale_x != $scale_y) {
if ($this->orig_w * $scale_y <= $this->thumb_w) {
$this->thumb_w = round($this->orig_w * $scale_y);
return;
}
if ($this->orig_h * $scale_x <= $this->thumb_h) {
$this->thumb_h = round($this->orig_h * $scale_x);
return;
}
}
}
}