Fix for RGBa PNG generator

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Fix

March 17, 2009 - 10:22am — bangpound

<?php
// $Id$ 
 
/**
 * @file rgbapng.module
 * @desc This module provides callbacks that generate transparent PNG for CSS backgrounds.
 *
 * DEPENDENCIES imageapi, imageapi_gd
 * USAGE in your theme stylesheets, use rules like this and in this order:
 * selector {
 *   background: url(rgbapng/FF000040);
 *   background: rgba(255,0,0,0.5);
 * }
 * You still need some PNG hack for <IE7 to display PNGs with alpha transparency
 * @link http://leaverou.me/2009/02/bulletproof-cross-browser-rgba-backgrounds/
 */
 
/**
 * Implementation of hook_menu()
 */
function rgbapng_menu() {
  $items = array();
//  If you use system_theme_data() to list themes, you can't ever enable
//  new themes at admin/build/themes. It's one of the ways Drupal is weird.
  $result = db_query("SELECT filename FROM {system} WHERE status = 1 AND type = 'theme'");
  while ($filename = db_result($result)) {
    $dir = dirname($filename);
    $items[$dir .'/rgbapng/%'] = array(
      'title' => 'RGBa PNG',
      'page callback' => 'rgbapng_image',
      'page arguments' => array(count(split('/', $dir)) + 1),
      'access callback' => TRUE,
      'type' => MENU_CALLBACK,
    );
  }
  return $items;
}
 
/*
 * feature taken from
 * http://leaverou.me/2009/02/bulletproof-cross-browser-rgba-backgrounds/
 */
function rgbapng_image($hex) {
  $file = file_create_path() .'/rgbapng/'. $hex .'.png';
  $dir = dirname($file);
  if (!file_check_directory($dir, FILE_CREATE_DIRECTORY) && !mkdir($dir, 0775, true)) {
    watchdog('rgbapng', 'Failed to create rgbapng directory: %dir', array('%dir' => $dir), WATCHDOG_ERROR);
    return false;
  }
  if (is_file($file)) {
    rgbapng_transfer($file);
  }
  $lockfile = file_directory_temp() .'/rgbapng' . basename($file);
  if (file_exists($lockfile)) {
    watchdog('rgbapng', 'RGBa PNG already generating: %dst, Lock file: %tmp.', array('%dst' => $file, '%tmp' => $lockfile), WATCHDOG_NOTICE);
    // 307 Temporary Redirect, to myself. Lets hope the image is done next time around.
    header('Location: '. request_uri(), TRUE, 307);
    exit;
  }
  touch($lockfile);
  // register the shtdown function to clean up lock files. by the time shutdown
  // functions are being called the cwd has changed from document root, to
  // server root so absolute paths must be used for files in shutdown functions.
  register_shutdown_function('file_delete', realpath($lockfile));
 
  list($r, $g, $b, $a) = imageapi_hex2rgba($hex);
 
  $image = new stdClass();
  $image->toolkit = 'imageapi_gd';
  $image->info = array(
    'width' => 1,
    'height' => 1,
    'extension' => 'png',
    'mime_type' => 'image/png',
  );
  $image->resource = @imagecreatetruecolor(1,1)
    or die('Cannot Initialize new GD image stream');
        imagealphablending($image->resource, FALSE);
        imagesavealpha($image->resource, TRUE);
 
        // Allocate our requested color
        $color = imagecolorallocatealpha($image->resource, $r, $g, $b, $a);
 
        // Fill the image with it
        imagefill($image->resource, 0, 0, $color);
  imageapi_image_close($image, $file);
  if (file_exists($file)) {
    rgbapng_transfer($file);
  }
  // Generate an error if image could not generate.
  watchdog('rgbapng', 'Failed generating an image from %hex using RGBa PNG.', array('%hex' => $hex), WATCHDOG_ERROR);
  header("HTTP/1.0 500 Internal Server Error");
  exit;
}
 
/**
 * STOLEN from imagecache_transfer
 * helper function to transfer files from rgbapng. Determines mime type and sets a last modified header.
 * @param $path path to file to be transferred.
 * @return <exit>
 */
 
function rgbapng_transfer($path) {
  $size = getimagesize($path);
  $headers = array('Content-Type: '. mime_header_encode($size['mime']));
 
  if ($fileinfo = stat($path)) {
    $headers[] = 'Content-Length: '. $fileinfo[7];
    _rgbapng_cache_set_cache_headers($fileinfo, $headers);
  }
  file_transfer($path, $headers);
  exit;
}
 
/**
 * STOLEN from _imagecache_cache_set_cache_headers
 * Set file headers that handle "If-Modified-Since" correctly for the
 * given fileinfo. Most code has been taken from drupal_page_cache_header().
 */
function _rgbapng_cache_set_cache_headers($fileinfo, &$headers) {
  // Set default values:
  $last_modified = gmdate('D, d M Y H:i:s', $fileinfo[9]) .' GMT';
  $etag = '"'. md5($last_modified) .'"';
 
  // See if the client has provided the required HTTP headers:
  $if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])
                        ? stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE'])
                        : false;
  $if_none_match = isset($_SERVER['HTTP_IF_NONE_MATCH'])
                    ? stripslashes($_SERVER['HTTP_IF_NONE_MATCH'])
                    : false;
 
  if ($if_modified_since && $if_none_match
      && $if_none_match == $etag // etag must match
      && $if_modified_since == $last_modified) { // if-modified-since must match
    header('HTTP/1.1 304 Not Modified');
    // All 304 responses must send an etag if the 200 response
    // for the same object contained an etag
    header('Etag: '. $etag);
    // We must also set Last-Modified again, so that we overwrite Drupal's
    // default Last-Modified header with the right one
    header('Last-Modified: '. $last_modified);
    exit;
  }
 
  // Send appropriate response:
  $headers[] = 'Last-Modified: '. $last_modified;
  $headers[] = 'ETag: '. $etag;
}

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<?php
// $Id$

/**
 * @file rgbapng.module
 * @desc This module provides callbacks that generate transparent PNG for CSS backgrounds.
 *
 * DEPENDENCIES imageapi, imageapi_gd
 * USAGE in your theme stylesheets, use rules like this and in this order:
 * selector {
 *   background: url(rgbapng/FF000040);
 *   background: rgba(255,0,0,0.5);
 * }
 * You still need some PNG hack for <IE7 to display PNGs with alpha transparency
 * @link http://leaverou.me/2009/02/bulletproof-cross-browser-rgba-backgrounds/
 */

/**
 * Implementation of hook_menu()
 */
function rgbapng_menu() {
  $items = array();
//  If you use system_theme_data() to list themes, you can't ever enable
//  new themes at admin/build/themes. It's one of the ways Drupal is weird.
  $result = db_query("SELECT filename FROM {system} WHERE status = 1 AND type = 'theme'");
  while ($filename = db_result($result)) {
    $dir = dirname($filename);
    $items[$dir .'/rgbapng/%'] = array(
      'title' => 'RGBa PNG',
      'page callback' => 'rgbapng_image',
      'page arguments' => array(count(split('/', $dir)) + 1),
      'access callback' => TRUE,
      'type' => MENU_CALLBACK,
    );
  }
  return $items;
}

/*
 * feature taken from
 * http://leaverou.me/2009/02/bulletproof-cross-browser-rgba-backgrounds/
 */
function rgbapng_image($hex) {
  $file = file_create_path() .'/rgbapng/'. $hex .'.png';
  $dir = dirname($file);
  if (!file_check_directory($dir, FILE_CREATE_DIRECTORY) && !mkdir($dir, 0775, true)) {
    watchdog('rgbapng', 'Failed to create rgbapng directory: %dir', array('%dir' => $dir), WATCHDOG_ERROR);
    return false;
  }
  if (is_file($file)) {
    rgbapng_transfer($file);
  }
  $lockfile = file_directory_temp() .'/rgbapng' . basename($file);
  if (file_exists($lockfile)) {
    watchdog('rgbapng', 'RGBa PNG already generating: %dst, Lock file: %tmp.', array('%dst' => $file, '%tmp' => $lockfile), WATCHDOG_NOTICE);
    // 307 Temporary Redirect, to myself. Lets hope the image is done next time around.
    header('Location: '. request_uri(), TRUE, 307);
    exit;
  }
  touch($lockfile);
  // register the shtdown function to clean up lock files. by the time shutdown
  // functions are being called the cwd has changed from document root, to
  // server root so absolute paths must be used for files in shutdown functions.
  register_shutdown_function('file_delete', realpath($lockfile));

list($r, $g, $b, $a) = imageapi_hex2rgba($hex);

$image = new stdClass();
  $image->toolkit = 'imageapi_gd';
  $image->info = array(
    'width' => 1,
    'height' => 1,
    'extension' => 'png',
    'mime_type' => 'image/png',
  );
  $image->resource = @imagecreatetruecolor(1,1)
    or die('Cannot Initialize new GD image stream');
	imagealphablending($image->resource, FALSE);
	imagesavealpha($image->resource, TRUE);

// Allocate our requested color
	$color = imagecolorallocatealpha($image->resource, $r, $g, $b, $a);

// Fill the image with it
	imagefill($image->resource, 0, 0, $color);
  imageapi_image_close($image, $file);
  if (file_exists($file)) {
    rgbapng_transfer($file);
  }
  // Generate an error if image could not generate.
  watchdog('rgbapng', 'Failed generating an image from %hex using RGBa PNG.', array('%hex' => $hex), WATCHDOG_ERROR);
  header("HTTP/1.0 500 Internal Server Error");
  exit;
}

/**
 * STOLEN from imagecache_transfer
 * helper function to transfer files from rgbapng. Determines mime type and sets a last modified header.
 * @param $path path to file to be transferred.
 * @return <exit>
 */

function rgbapng_transfer($path) {
  $size = getimagesize($path);
  $headers = array('Content-Type: '. mime_header_encode($size['mime']));

if ($fileinfo = stat($path)) {
    $headers[] = 'Content-Length: '. $fileinfo[7];
    _rgbapng_cache_set_cache_headers($fileinfo, $headers);
  }
  file_transfer($path, $headers);
  exit;
}

/**
 * STOLEN from _imagecache_cache_set_cache_headers
 * Set file headers that handle "If-Modified-Since" correctly for the
 * given fileinfo. Most code has been taken from drupal_page_cache_header().
 */
function _rgbapng_cache_set_cache_headers($fileinfo, &$headers) {
  // Set default values:
  $last_modified = gmdate('D, d M Y H:i:s', $fileinfo[9]) .' GMT';
  $etag = '"'. md5($last_modified) .'"';

// See if the client has provided the required HTTP headers:
  $if_modified_since = isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])
                        ? stripslashes($_SERVER['HTTP_IF_MODIFIED_SINCE'])
                        : false;
  $if_none_match = isset($_SERVER['HTTP_IF_NONE_MATCH'])
                    ? stripslashes($_SERVER['HTTP_IF_NONE_MATCH'])
                    : false;

if ($if_modified_since && $if_none_match
      && $if_none_match == $etag // etag must match
      && $if_modified_since == $last_modified) { // if-modified-since must match
    header('HTTP/1.1 304 Not Modified');
    // All 304 responses must send an etag if the 200 response
    // for the same object contained an etag
    header('Etag: '. $etag);
    // We must also set Last-Modified again, so that we overwrite Drupal's
    // default Last-Modified header with the right one
    header('Last-Modified: '. $last_modified);
    exit;
  }

// Send appropriate response:
  $headers[] = 'Last-Modified: '. $last_modified;
  $headers[] = 'ETag: '. $etag;
}

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Fix for RGBa PNG generator

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