Posts Tagged ‘image manipulation’

Posted on June 28, 2004 - by snipe

Cropped Thumbnails using PHP and the GD Library

This code will allow you to create a thumbnail from a segment of the image. In some situations, you want to thumbnail an entire image - but other times, you may want only a piece - for example if you wish to generate square thumbnail images regardless of whether or not the original image is landscape or portrait style.

The basics are as follows:

1. Resize the image, using the $newthumb size value as the SMALLEST measurement (height in the case of landscape images, width in the case or portrait images). So if you had an original image that is 400 pixels wide and 200 pixels tall, it would set the height to 60 (since 60 is the $newthumb height we’ve used in the example below) and then resize the width down according to whatever ratio is that will contrain the proportions.
2. Trim off the extra so that the end thumb is 60×60.

<?php

$orig_path = ‘/path/to/original/file/’;
$micro_path = ‘/path/to/cropped/file/’;
$imagefilename = ‘myimage.jpg’;

$size = getimagesize($orig_path.$imagefilename);

/**
* new cropped thumbnail sizes
*/
$newthumb_width = 60;
$newthumb_height = 60;

/**
* assign friendlier values to getimagesize data
*/
$orig_width = $size[0];
$orig_height= $size[1];

$width_ratio = ($newthumb_width / $orig_width );
$height_ratio = ($newthumb_height / $orig_height);

if ($orig_width > $orig_height ) {
// this is a landscape image
$crop_width = round($orig_width * $height_ratio);
$crop_height = $newthumb_height;

} elseif ($orig_width < $orig_height ) {
// this is a portrait image
$crop_height = round($orig_height * $width_ratio);
$crop_width = $newthumb_width;

} else {
// this is a square image
$crop_width = $newthumb_width;
$crop_height = $newthumb_height;
}

$source_img = imagecreatefromjpeg($orig_path.$imagefilename);
$dest_img = imagecreatetruecolor($newthumb_width,$newthumb_height);

/**
* if you want to crop from a specific area, for example, if you
* want to crop the image from the middle instead of the top left,
* you’ll need to do some more math to replace the 0,0,0,0 bits here.
*/
imagecopyresampled($dest_img, $source_img, 0 , 0 , 0, 0, $crop_width, $crop_height, $orig_width, $orig_height);
imagejpeg($dest_img, $micro_path.$imagefilename);
imagedestroy($dest_img);
?>

Posted on June 27, 2004 - by snipe

Dynamic Watermarks/Text Overlay on Images in PHP

This code can be useful for a number of things, such as making dynamic banners or for adding a copyright type of watermark to photographs or artwork (as we do in snipe gallery). As usual, this will not work for gifs unless you have a version of gd that lets you do that (cuz the folks at Unisys are a bunch of mo-mos).

The example here is taken from the Godsmack sig generator, so it’s designed to create white text with a black drop shadow on a preformatted blank banner.
Note: Remember that PHP must be compiled with jpeg/png/gd support, AND that the font file must be uploaded to the server for this to work. For our purposes, we’ll assume you’re going to take this snippet and make it into its own file, which we’ll call “mkwatermark.php”.

<?php
/* ———————————————- */
/* ———— BEGIN PHP SNIPPET —————-*/
/* ———————————————- */
// specify the file name - you can use a full path, or “../../” type stuff here
// if the image is not in the same directory as this code file
$image = imagecreatefrompng(“gs-banner-sm.png”);

// specify the font size
$font_size = 14;

// in this case, the color is white, but you can replace the numbers with the RGB values
// of any color you want
$color = imagecolorallocate($image, 255,255,255);

// make our drop shadow color
$black = imagecolorallocate($image, 0,0,0);

// and now we do the overlay - the layers of text start top to bottom, so
// the drop shadow comes first

// $image - the base image file we specified above
// $font_size - Well duh. Its the size of the font
// 0 - the angle of the text - we don’t want an angle, so we leave it at 0
// 55 - pixels to the right from the leftmost part of the image
// 35 - pixels down from the top of the image
// $black - the color we defined above
// “../fonts/ARIALBD.TTF” - the location on the server that the font can be found
// “Test Text” - the text we’re overlaying - you can also use a variable here
ImageTTFText ($image, $font_size, 0, 56, 36, $black, “../fonts/ARIALBD.TTF”,“Test Text”);

// Now add the actual white text “on top”
ImageTTFText ($image, $font_size, 0, 55, 35, $color, “../fonts/ARIALBD.TTF”,“Test Text”);
header(“Content-type: image/png”);
imagepng($image);
imagedestroy($image);
}

?>

To print out the image, we would just have to wite the html as:

<img src="mkwatermark.php">

Note about Variables - If you are using any variables outside the file to determine what the code does (for example, making the text a variable as we do with the Godsmack sig generator), be sure to secure your code and check to be sure the user can’t do any damage to your system by entering harmful values.

Posted on June 27, 2004 - by snipe

Dynamic thumbnailing with PHP and the GD library

Although there are loads of ways you can do this, for this example, we’re assuming that the fullsize image is located in a directory called “images”, and the thumbnails will have the same name as the fullsize, but will be copied into a directory called “thumbs”.

<?php
// find out the current size info
$photo_filename = “myimage.jpg”
$path = “/home/snipe/www/images/”;
$image_stats = GetImageSize($path.$photo_filename);
$imagewidth = $image_stats[0];
$imageheight = $image_stats[1];
$img_type = $image_stats[2];
$new_w = 100; $ratio = ($imagewidth / $new_w);
$new_h = round($imageheight / $ratio);

// Find out if we need to resize it by checking to
// see if the original image is larger than the
// defined new width, and making sure the
// resized version does not exist yet

if (($imagewidth > $new_w)&& (!file_exists($path.$photo_filename))) {

// if this is a jpeg, resize as a jpeg
if ($img_type==2) {

$src_img = imagecreatefromjpeg($path.$photo_filename);
$dst_img = imagecreate($new_w,$new_h);
imagecopyresized($dst_img,$src_img,0,0,0,0,$new_w,$new_h,imagesx($src_img),imagesy($src_img));
imagejpeg($dst_img, $path.$photo_filename);

} elseif ($img_type==3) {
// if image is a png, copy it

$dst_img=ImageCreate($new_w,$new_h);
$src_img=ImageCreateFrompng($path.$photo_filename);
ImageCopyResized($dst_img,$src_img,0,0,0,0,$new_w,$new_h,ImageSX($src_img),ImageSY($src_img));
Imagepng($dst_img, $path.$photo_filename);

// Normally if image is neither png nor jpeg
// (ie, invalid image or a gif file), I use
// the fullsize as the thumbnail and just
// resize it through the html size tags. For this
// example tho, we’ll pretend we have a version of
// Gdlib that can handle gif resizing

} elseif ($img_type==1) {

$dst_img=ImageCreate($new_w,$new_h);
$src_img=ImageCreateFromGif($path.$photo_filename);
ImageCopyResized($dst_img,$src_img,0,0,0,0,$new_w,$new_h,ImageSX($src_img),ImageSY($src_img));
ImageGif($dst_img, $path.$photo_filename);

} else {
// if it doesn’t show up as any of the valid formats, give an error
echo ‘error’;

} // endif img_type sequence

}

?>

Posted on June 27, 2004 - by snipe

Dynamic thumbnailing with PHP and Imagemagick

This code formatting is a little off, since the WYSIWG editor seems to have eaten part of it. Sorry.

<?php

/* ———————————————- */
/* ———— BEGIN PHP SNIPPET —————-*/
/* ———————————————- */
// specify your file details
$current_file = “image.jpg”;
$max_width = “150″;

// get the current info on the file
$current_size = getimagesize($current_file);
$current_img_width = $current_size[0];
$current_img_height = $current_size[1];
$image_base = explode(“.”, $current_file);

// this part gets the new thumbnail name
$image_basename = $image_base[0];
$image_ext = $image_base[1];
$thumb_name = $image_basename.“-th.”.$image_ext;

// determine if the image actually needs to be resized
// and if it does, get the new height for it
if ($current_img_width > $max_width) {
$too_big_diff_ratio = $current_img_width/$max_width;
$new_img_width = $max_width;
$new_img_height = round($current_img_height/$too_big_diff_ratio);

// presto chango alacazam
$make_magick = system(“convert -geometry $new_img_width x $new_img_height $current_file $thumb_name”, $retval);

// let us know if it worked or not
if (!($retval)) {
echo “Thumbnail created  -”.$thumb_name;
} else {
echo “Oops - no dice! Script failed cuz your momma doesn’t love you.”;
}
} else {
echo “No need to resize! You’re perfect just the way you are.”;
}

?>