class CaptchaImageResponse in CAPTCHA 8
Response which is returned as the captcha for image_captcha.
@package Drupal\image_captcha\Response
Hierarchy
- class \Drupal\image_captcha\Response\CaptchaImageResponse extends \Symfony\Component\HttpFoundation\Response
Expanded class hierarchy of CaptchaImageResponse
1 file declares its use of CaptchaImageResponse
- CaptchaImageGeneratorController.php in image_captcha/
src/ Controller/ CaptchaImageGeneratorController.php
File
- image_captcha/
src/ Response/ CaptchaImageResponse.php, line 17
Namespace
Drupal\image_captcha\ResponseView source
class CaptchaImageResponse extends Response {
const LOG_LEVEL = 'ERROR';
/**
* Database connection configuration container.
*
* @var \Drupal\Core\Database\Connection
*/
protected $connection;
/**
* Image Captcha config storage.
*
* @var \Drupal\Core\Config\Config
*/
protected $config;
/**
* File System container.
*
* @var \Drupal\Core\File\FileSystemInterface
*/
protected $fileSystem;
/**
* Watchdog logger channel for captcha.
*
* @var \Psr\Log\LoggerInterface
*/
protected $logger;
/**
* Recourse with generated image.
*
* @var resource
*/
protected $image;
/**
* {@inheritdoc}
*/
public function __construct(Config $config, LoggerInterface $logger, Connection $connection, FileSystemInterface $fileSystem, $callback = NULL, $status = 200, $headers = []) {
parent::__construct(NULL, $status, $headers);
$this->config = $config;
$this->logger = $logger;
$this->connection = $connection;
$this->fileSystem = $fileSystem;
}
/**
* {@inheritdoc}
*/
public function prepare(Request $request) {
$session_id = $request
->get('session_id');
$code = $this->connection
->select('captcha_sessions', 'cs')
->fields('cs', [
'solution',
])
->condition('csid', $session_id)
->execute()
->fetchField();
if ($code !== FALSE) {
$this->image = @$this
->generateImage($code);
if (!$this->image) {
$this->logger
->log(self::LOG_LEVEL, 'Generation of image CAPTCHA failed. Check your image CAPTCHA configuration and especially the used font.', []);
}
}
return parent::prepare($request);
}
/**
* {@inheritdoc}
*/
public function sendHeaders() {
if ($this->config
->get('image_captcha_file_format') == IMAGE_CAPTCHA_FILE_FORMAT_JPG) {
$this->headers
->set('content-type', 'image/jpeg');
}
else {
$this->headers
->set('content-type', 'image/png');
}
return parent::sendHeaders();
}
/**
* {@inheritdoc}
*/
public function sendContent() {
if (!$this->image) {
return;
}
// Begin capturing the byte stream.
ob_start();
$file_format = $this->config
->get('image_captcha_file_format');
if ($file_format == IMAGE_CAPTCHA_FILE_FORMAT_JPG) {
imagejpeg($this->image);
}
else {
imagepng($this->image);
}
// Clean up the image resource.
imagedestroy($this->image);
}
/**
* Small helper function for parsing a hexadecimal color to a RGB tuple.
*
* @param string $hex
* String representation of HEX color value.
*
* @return array
* Array representation of RGB color value.
*/
protected function hexToRgb($hex) {
if (strlen($hex) == 4) {
$hex = $hex[1] . $hex[1] . $hex[2] . $hex[2] . $hex[3] . $hex[3];
}
$c = hexdec($hex);
$rgb = [];
for ($i = 16; $i >= 0; $i -= 8) {
$rgb[] = $c >> $i & 0xff;
}
return $rgb;
}
/**
* Base function for generating a image CAPTCHA.
*
* @param string $code
* String code to be presented on image.
*
* @return resource
* Image to be outputted contained $code string.
*/
protected function generateImage($code) {
$fonts = _image_captcha_get_enabled_fonts();
$font_size = $this->config
->get('image_captcha_font_size');
list($width, $height) = _image_captcha_image_size($code);
$image = imagecreatetruecolor($width, $height);
if (!$image) {
return FALSE;
}
// Get the background color and paint the background.
$background_rgb = $this
->hexToRGB($this->config
->get('image_captcha_background_color'));
$background_color = imagecolorallocate($image, $background_rgb[0], $background_rgb[1], $background_rgb[2]);
// Set transparency if needed.
$file_format = $this->config
->get('image_captcha_file_format');
if ($file_format == IMAGE_CAPTCHA_FILE_FORMAT_TRANSPARENT_PNG) {
imagecolortransparent($image, $background_color);
}
imagefilledrectangle($image, 0, 0, $width, $height, $background_color);
$result = $this
->printString($image, $width, $height, $fonts, $font_size, $code);
if (!$result) {
return FALSE;
}
$noise_colors = [];
for ($i = 0; $i < 20; $i++) {
$noise_colors[] = imagecolorallocate($image, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
}
// Add additional noise.
if ($this->config
->get('image_captcha_dot_noise')) {
$this
->addDots($image, $width, $height, $noise_colors);
}
if ($this->config
->get('image_captcha_line_noise')) {
$this
->addLines($image, $width, $height, $noise_colors);
}
$distortion_amplitude = 0.25 * $font_size * $this->config
->get('image_captcha_distortion_amplitude') / 10.0;
if ($distortion_amplitude > 1) {
$wavelength_xr = (2 + 3 * lcg_value()) * $font_size;
$wavelength_yr = (2 + 3 * lcg_value()) * $font_size;
$freq_xr = 2 * 3.141592 / $wavelength_xr;
$freq_yr = 2 * 3.141592 / $wavelength_yr;
$wavelength_xt = (2 + 3 * lcg_value()) * $font_size;
$wavelength_yt = (2 + 3 * lcg_value()) * $font_size;
$freq_xt = 2 * 3.141592 / $wavelength_xt;
$freq_yt = 2 * 3.141592 / $wavelength_yt;
$distorted_image = imagecreatetruecolor($width, $height);
if ($file_format == IMAGE_CAPTCHA_FILE_FORMAT_TRANSPARENT_PNG) {
imagecolortransparent($distorted_image, $background_color);
}
if (!$distorted_image) {
return FALSE;
}
if ($this->config
->get('image_captcha_bilinear_interpolation')) {
// Distortion with bilinear interpolation.
for ($x = 0; $x < $width; $x++) {
for ($y = 0; $y < $height; $y++) {
// Get distorted sample point in source image.
$r = $distortion_amplitude * sin($x * $freq_xr + $y * $freq_yr);
$theta = $x * $freq_xt + $y * $freq_yt;
$sx = $x + $r * cos($theta);
$sy = $y + $r * sin($theta);
$sxf = (int) floor($sx);
$syf = (int) floor($sy);
if ($sxf < 0 || $syf < 0 || $sxf >= $width - 1 || $syf >= $height - 1) {
$color = $background_color;
}
else {
// Bilinear interpolation: sample at four corners.
$color_00 = imagecolorat($image, $sxf, $syf);
$color_00_r = $color_00 >> 16 & 0xff;
$color_00_g = $color_00 >> 8 & 0xff;
$color_00_b = $color_00 & 0xff;
$color_10 = imagecolorat($image, $sxf + 1, $syf);
$color_10_r = $color_10 >> 16 & 0xff;
$color_10_g = $color_10 >> 8 & 0xff;
$color_10_b = $color_10 & 0xff;
$color_01 = imagecolorat($image, $sxf, $syf + 1);
$color_01_r = $color_01 >> 16 & 0xff;
$color_01_g = $color_01 >> 8 & 0xff;
$color_01_b = $color_01 & 0xff;
$color_11 = imagecolorat($image, $sxf + 1, $syf + 1);
$color_11_r = $color_11 >> 16 & 0xff;
$color_11_g = $color_11 >> 8 & 0xff;
$color_11_b = $color_11 & 0xff;
// Interpolation factors.
$u = $sx - $sxf;
$v = $sy - $syf;
$r = (int) ((1 - $v) * ((1 - $u) * $color_00_r + $u * $color_10_r) + $v * ((1 - $u) * $color_01_r + $u * $color_11_r));
$g = (int) ((1 - $v) * ((1 - $u) * $color_00_g + $u * $color_10_g) + $v * ((1 - $u) * $color_01_g + $u * $color_11_g));
$b = (int) ((1 - $v) * ((1 - $u) * $color_00_b + $u * $color_10_b) + $v * ((1 - $u) * $color_01_b + $u * $color_11_b));
$color = ($r << 16) + ($g << 8) + $b;
}
imagesetpixel($distorted_image, $x, $y, $color);
}
}
}
else {
// Distortion with nearest neighbor interpolation.
for ($x = 0; $x < $width; $x++) {
for ($y = 0; $y < $height; $y++) {
// Get distorted sample point in source image.
$r = $distortion_amplitude * sin($x * $freq_xr + $y * $freq_yr);
$theta = $x * $freq_xt + $y * $freq_yt;
$sx = $x + $r * cos($theta);
$sy = $y + $r * sin($theta);
$sxf = (int) floor($sx);
$syf = (int) floor($sy);
if ($sxf < 0 || $syf < 0 || $sxf >= $width - 1 || $syf >= $height - 1) {
$color = $background_color;
}
else {
$color = imagecolorat($image, $sxf, $syf);
}
imagesetpixel($distorted_image, $x, $y, $color);
}
}
}
imagedestroy($image);
return $distorted_image;
}
else {
return $image;
}
}
/**
* Add random noise lines to image with given color.
*
* @param resource $image
* Link to image stream resource.
* @param int $width
* Suggested output image width.
* @param int $height
* Suggested input image width.
* @param array $colors
* Font color.
*/
protected function addLines(&$image, $width, $height, array $colors) {
$line_quantity = $width * $height / 200.0 * (int) $this->config
->get('image_captcha_noise_level') / 10.0;
for ($i = 0; $i < $line_quantity; $i++) {
imageline($image, mt_rand(0, $width), mt_rand(0, $height), mt_rand(0, $width), mt_rand(0, $height), $colors[array_rand($colors)]);
}
}
/**
* Add random noise dots to image with given color.
*
* @param resource $image
* Link to image stream resource.
* @param int $width
* Suggested output image width.
* @param int $height
* Suggested input image width.
* @param array $colors
* Font color.
*/
protected function addDots(&$image, $width, $height, array $colors) {
$noise_quantity = $width * $height * (int) $this->config
->get('image_captcha_noise_level') / 10.0;
for ($i = 0; $i < $noise_quantity; $i++) {
imagesetpixel($image, mt_rand(0, $width), mt_rand(0, $height), $colors[array_rand($colors)]);
}
}
/**
* Helper function for drawing text on the image.
*
* @param resource $image
* Link to image stream resource.
* @param int $width
* Suggested output image width.
* @param int $height
* Suggested input image width.
* @param array $fonts
* Array of fonts names and paths.
* @param int $font_size
* Suggested font size.
* @param string $text
* Text to be written on the image.
* @param bool $rtl
* RTL.
*
* @return bool
* TRUE if image generation was successful, FALSE otherwise.
*/
protected function printString(&$image, $width, $height, array $fonts, $font_size, $text, $rtl = FALSE) {
$characters = _image_captcha_utf8_split($text);
$character_quantity = count($characters);
$foreground_rgb = $this
->hexToRgb($this->config
->get('image_captcha_foreground_color'));
$foreground_color = imagecolorallocate($image, $foreground_rgb[0], $foreground_rgb[1], $foreground_rgb[2]);
// Precalculate the value ranges for color randomness.
$foreground_randomness = $this->config
->get('image_captcha_foreground_color_randomness');
$foreground_color_range = [];
if ($foreground_randomness) {
for ($i = 0; $i < 3; $i++) {
$foreground_color_range[$i] = [
max(0, $foreground_rgb[$i] - $foreground_randomness),
min(255, $foreground_rgb[$i] + $foreground_randomness),
];
}
}
// Set default text color.
$color = $foreground_color;
// The image is separated in different character cages, one for
// each character that will be somewhere inside that cage.
$ccage_width = $width / $character_quantity;
$ccage_height = $height;
foreach ($characters as $c => $character) {
// Initial position of character: in the center of its cage.
$center_x = ($c + 0.5) * $ccage_width;
if ($rtl) {
$center_x = $width - $center_x;
}
$center_y = 0.5 * $height;
// Pick a random font from the list.
$font = $fonts[array_rand($fonts)];
$font = _image_captcha_get_font_uri($font);
// Get character dimensions for TrueType fonts.
if ($font != 'BUILTIN') {
putenv('GDFONTPATH=' . realpath('.'));
$bbox = imagettfbbox($font_size, 0, $this->fileSystem
->realpath($font), $character);
// In very rare cases with some versions of the GD library, the x-value
// of the left side of the bounding box as returned by the first call of
// imagettfbbox is corrupt (value -2147483648 = 0x80000000).
// The weird thing is that calling the function a second time
// can be used as workaround.
// This issue is discussed at http://drupal.org/node/349218.
if ($bbox[2] < 0) {
$bbox = imagettfbbox($font_size, 0, $this->fileSystem
->realpath($font), $character);
}
}
else {
$character_width = imagefontwidth(5);
$character_height = imagefontheight(5);
$bbox = [
0,
$character_height,
$character_width,
$character_height,
$character_width,
0,
0,
0,
];
}
// Random (but small) rotation of the character.
// @todo add a setting for this?
$angle = mt_rand(-10, 10);
// Determine print position: at what coordinate should the character be
// printed so that the bounding box would be nicely centered in the cage?
$bb_center_x = 0.5 * ($bbox[0] + $bbox[2]);
$bb_center_y = 0.5 * ($bbox[1] + $bbox[7]);
$angle_cos = cos($angle * 3.1415 / 180);
$angle_sin = sin($angle * 3.1415 / 180);
$pos_x = $center_x - ($angle_cos * $bb_center_x + $angle_sin * $bb_center_y);
$pos_y = $center_y - (-$angle_sin * $bb_center_x + $angle_cos * $bb_center_y);
// Calculate available room to jitter: how much
// can the character be moved. So that it stays inside its cage?
$bb_width = $bbox[2] - $bbox[0];
$bb_height = $bbox[1] - $bbox[7];
$dev_x = 0.5 * max(0, $ccage_width - abs($angle_cos) * $bb_width - abs($angle_sin) * $bb_height);
$dev_y = 0.5 * max(0, $ccage_height - abs($angle_cos) * $bb_height - abs($angle_sin) * $bb_width);
// Add jitter to position.
$pos_x = $pos_x + mt_rand(-$dev_x, $dev_x);
$pos_y = $pos_y + mt_rand(-$dev_y, $dev_y);
// Calculate text color in case of randomness.
if ($foreground_randomness) {
$color = imagecolorallocate($image, mt_rand($foreground_color_range[0][0], $foreground_color_range[0][1]), mt_rand($foreground_color_range[1][0], $foreground_color_range[1][1]), mt_rand($foreground_color_range[2][0], $foreground_color_range[2][1]));
}
// Draw character.
if ($font == 'BUILTIN') {
imagestring($image, 5, $pos_x, $pos_y, $character, $color);
}
else {
imagettftext($image, $font_size, $angle, $pos_x, $pos_y, $color, $this->fileSystem
->realpath($font), $character);
}
}
return TRUE;
}
}Members
Name |
Modifiers | Type | Description | Overrides |
|---|---|---|---|---|
|
CaptchaImageResponse:: |
protected | property | Image Captcha config storage. | |
|
CaptchaImageResponse:: |
protected | property | Database connection configuration container. | |
|
CaptchaImageResponse:: |
protected | property | File System container. | |
|
CaptchaImageResponse:: |
protected | property | Recourse with generated image. | |
|
CaptchaImageResponse:: |
protected | property | Watchdog logger channel for captcha. | |
|
CaptchaImageResponse:: |
protected | function | Add random noise dots to image with given color. | |
|
CaptchaImageResponse:: |
protected | function | Add random noise lines to image with given color. | |
|
CaptchaImageResponse:: |
protected | function | Base function for generating a image CAPTCHA. | |
|
CaptchaImageResponse:: |
protected | function | Small helper function for parsing a hexadecimal color to a RGB tuple. | |
|
CaptchaImageResponse:: |
constant | |||
|
CaptchaImageResponse:: |
public | function | Prepares the Response before it is sent to the client. | |
|
CaptchaImageResponse:: |
protected | function | Helper function for drawing text on the image. | |
|
CaptchaImageResponse:: |
public | function | Sends content for the current web response. | |
|
CaptchaImageResponse:: |
public | function | Sends HTTP headers. | |
|
CaptchaImageResponse:: |
public | function | Constructor. |