note 42239 added to function.imagecopy

Although the following function doesn't use imagecopy(), I thought it might help in related tasks. Please see the code comments for details of it's operation. I made this function to assist in creating images using multiple "layers". For example if you wanted to dynamically create a logo image with seperate colors for say the logo itself and a glow around the logo, these steps would be followed: -Using an image editor (like Photoshop), create a png-24 image with just the logo on a transparent background. The logo can be any color or multiple colors, but the final image created by this function will be of a single color. -Create a similar image with just the glow (no logo) -Create a background image -Apply this colorize() function to the logo image and the glow image with your desired color for each. -You can now use imagecopy() to merge all three into a single image ready for a browser. Here's the code <?php /*======Colorize===== (requires GD 2.0.1 or greater) This function requires the following arguments: $src_path = A string representing the relative path to the src image. Ex: "images/myimage.png". This image must be a png-24 with an alpha channel. $dest_path = A string representing the relative path to the image to be created. $hex_color = A string representing a color in html format, including the # sign. Ex: "#D2E5FF" This function examines the transparency of the source image, pixel by pixel, and creates a new one-color image with this same "transparency map". ====================*/ function colorize($src_path, $dest_path, $hex_color) { //get the png-24 image - it must have an alpha channel for this funciton to be effective $src = imagecreatefrompng($src_path); //get width $w = imagesx($src); //get height $h = imagesy($src); //create same size destination image $dest = imagecreatetruecolor($w, $h); //this must be set to false in order to be able to overwright the defualt black pixels of the background with our new //transparent pixels. Otherwise our new pixel would just be applied on top of the black. imagealphablending($dest, false); //get decimal components of the passed hex color $red = hexdec(substr($hex_color, 1, 2)); $green = hexdec(substr($hex_color, 3, 2)); $blue = hexdec(substr($hex_color, 5, 2)); for ($i = 0; $i < $h; $i++) { //this loop traverses each row in the image for ($j = 0; $j < $w; $j++) { //this loop traverses each pixel of each row //get the color & alpha info of the current pixel $retrieved_color = imagecolorat($src, $j, $i); //put this info into an array $rgba_array = imagecolorsforindex($src, $retrieved_color); //get the transparency of the pixel as a number from 0 (opaque) to 127 (transparent) $alpha = $rgba_array['alpha']; //allocate the color to paint. Note that we may continue to overwright this color since our image is not palleted $color_to_paint = imagecolorallocatealpha($dest, $red, $green, $blue, $alpha); //paint the pixel imagesetpixel($dest, $j, $i, $color_to_paint); } } //this allows the new transparency info to be saved with the image imagesavealpha($dest, true); //write the image to the destination file imagepng($dest, $dest_path); } ?> ---- Manual Page -- http://www.php.net/manual/en/function.imagecopy.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+42239 Delete -- http://master.php.net/manage/user-notes.php?action=delete+42239&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+42239&report=yes Search -- http://master.php.net/manage/user-notes.php