GD img refresh issues

binaryisdeath

here is the dealio

my setup
html contained in a .inc file that is called by an index.php (through switch statements)

in that file in html is displayed a form with text field input for a UPC 12 digit string

next to this is an img tag calling barcodetest.png

my form sends the string back to index.php which calls barcode.php functions to create a png file and save it as barcodetest.png

all this is working, the png file is being redrawn each time the generate button is clicked

after that

through include("index.inc");
i am dumping the user back at the page they began at bu expect the img file to update

it is not due to img caching garbage

i am using meta tags to force no-cache, etc but this just ain't doing it

i even tried adding a unix timestamp to the end of the img src tag
as in <img src="barcodetest.png?<?php echo getdate($timestamp) ?>"

no success

how do i force a reload

can i do this in php after i update the image

here is what i have in my switch statement in index.php

require("_barcode_upc.inc");
$im2 = barcode_generate_upca("$GenerateID", false, 100, 20, 1);
Header("Content-type: image/png");
ImagePNG($im2,'images/barcodetest.png');
include("index.inc");
exit();

please help

nathanAThactivistDOTcom

you can see what i mean at www.hactivist.com/recode

just a silly art project
never for profit

Mordecai

Try putting this in the image file itself:
header("Pragma: no-cache");
header("Cache-Control: no-store, no-cache, must-revalidate");

binaryisdeath

hmmm

i may be a dumb arse right now
but how do i do that specifically
do i need to put the image i am creating in a seperate folder?
since the image gets regenerated how do i add that header info to the image

binaryisdeath

require("_barcode_upc.inc");
$im2 = barcode_generate_upca("$GenerateID", false, 100, 20, 1);
Header("Content-type: image/png");
Header("Pragma: no-cache");
Header("Cache-Control: no-store, no-cache, must-revalidate");
ImagePNG($im2,'images/barcodetest.png');
include("index.inc");
exit();

still isn't working

Mordecai

Isn't the image being generated by GD? Just put it in with imagecreate().

binaryisdeath

i thought that was what i was doing as i ccp'd in the previous reply, setting the headers on the png file right?

i am new to using GD really, and as far as I know, i didn't think i could set up headers when just calling the imagecreate function

is that an incorrect assumption

again here is where i was calling the my function

	require("_barcode_upc.inc");
	$im2 = barcode_generate_upca("$GenerateID", false, 100, 20, 1);
	Header("Content-type: image/png");
	Header("Pragma: no-cache"); 
	Header("Cache-Control: no-store, no-cache, must-revalidate");
	ImagePNG($im2,'images/barcodetest.png');
	include("index.inc");
	exit();

and here is a little snippit from what i am doing in barcode_generate_upca ()

function barcode_generate_upca($barcode_text, $show_text = true, $bar_height = 150, $text_size = 20, $element_width = 2)
{
$data = barcode_encode_upca($barcode_text);
$text_font = "verdana.ttf";

    if($show_text) {
            list($pos_blx, $pos_bly, $pos_brx, $pos_bry, $pos_trx, $pos_try, $pos_tlx, $pos_tly) = ImageTTFBBox($text_size, 0, $text_font, substr($barcode_text, 0, 1));
            $digit_width = $pos_trx-$pos_tlx;
            $margin_width = ($element_width*4)+$digit_width;
    } else {
            $margin_width = ($element_width*2);
    }

    $width = strlen($data);
    $image_width = ($margin_width*2)+($element_width*$width);
    $im = ImageCreate($image_width, $bar_height+($show_text?$text_size * 2:0));

    $white = ImageColorAllocate($im, 255, 255, 255);
    $black = ImageColorAllocate($im, 0, 0, 0);

    $y = 10;
    $x = $margin_width;

    for($a = 0; $a<strlen($data); $a++) {

            $color = substr($data, $a, 1)=="1"?$black:$white;

            ImageFilledRectangle($im, $x, $y, $x+$element_width, $y+$bar_height, $color);

            $x += $element_width;
    }

then blah blah blah i return ($im)