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Web Technologies-I

Notes 12.4.1 Images
PDF supports many different embedded image formats: PNG, JPEG, GIF, TIFF, CCITT, and a
raw image format that consists of a stream of the exact byte sequence of pixels. Not every feature
of every format is supported, however.
For PNG images, the alpha channel is lost (however, the later versions of pdflib and Acrobat
do support transparency, which means that you can indicate a color index to be the transparent
color, but you cannot have partial transparency). For JPEG, you only need to watch out for
progressive JPEGs; they are not supported prior to Acrobat 4, so it is a good idea to stick to non
progressive JPEGs. For GIF images, avoid interlacing.
Adding an image to a PDF document is relatively simple. The first step is to call the appropriate
open function for the type of image you are using. These functions all take the form pdf_open_
format( ). For instance:
$image = pdf_open_jpeg (pdf, filename);
Once you have opened the image, use pdf_place_image( ) to indicate where in your document
the image should be located. While you have an image open, you can place it multiple times
throughout your document; your generated file will contain only one copy of the actual image
data. When you are done placing your image, call the pdf_close_image( ) function:
pdf_place_image(pdf, image, x, y, scale); pdf_close_image(pdf, image);

You can get the dimensions of an image via pdf_get_value( ) calls on the imagewidth and
imageheight keywords.

Placing and scaling images

<?php

$p = pdf_new( );
pdf_open_file($p);
pdf_set_info($p,”Creator”,”images.php”);

pdf_set_info($p,”Author”,”ABC”);

pdf_set_info($p,”Title”,”Images”);
pdf_begin_page($p,612,792);
$im = pdf_open_jpeg($p, “php-big.jpg”);

pdf_place_image($p, $im, 200, 700, 1.0);

pdf_place_image($p, $im, 200, 600, 0.75);
pdf_place_image($p, $im, 200, 535, 0.50);
pdf_place_image($p, $im, 200, 501, 0.25);

pdf_place_image($p, $im, 200, 486, 0.10);

$x = pdf_get_value($p, “imagewidth”, $im);
$y = pdf_get_value($p, “imageheight”, $im);
pdf_close_image ($p,$im);

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