patrick89 Posted November 12, 2009 Share Posted November 12, 2009 Hi everyone, I'm playing around with PHP at the moment to make a graph (first time really using the image drawing functions in PHP, so it's a bit of an experiment at the moment). All was going well until I tried to use a function within the code. If I try to call a function which isn't one of the PHP image functions, the image doesn't display? For example, including drawTimeLine() stops the image from displaying (simplified version of the code i've been working on but has the same problem...): <?php header("Content-type: image/png"); $timelineGraph = ImageCreate(300,300) or die("Cannot Initialize new GD image stream"); // Formatting $black = ImageColorAllocate($timelineGraph, 0, 0, 0); $red = ImageColorAllocate($timelineGraph, 255, 0, 0); function drawTimeline($startWeek, $startDay, $endWeek, $endDay) { ImageLine($timelineGraph, 0, 0, 299, 299, $red); } drawTimeline(1,1,1,1); ImagePng($timelineGraph); ImageDestroy($timelineGraph); ?> While if you comment drawTimeline() out, the image will still appear (just as a black background, but still appears on screen). I'm inserting it using the following code which I believe is right? <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html> <head> <title>Timeline Graph</title> </head> <body> <p><img src="test.php" alt="Graph" /></p> </body> </html> Can't work out what the problem is? Does PHP not allow for custom functions within image creation? Any help is much appreciated... I can't work out why this isn't working! I was going well up until now! Link to comment https://forums.phpfreaks.com/topic/181229-strange-issue-with-custom-function-and-image-drawing/ Share on other sites More sharing options...
Alex Posted November 12, 2009 Share Posted November 12, 2009 When working with images if you can't figure out the problem it's usually a good idea to comment out the Content-type header so that you can see the error you're getting. In your case you have a scope problem. Neither $timelineGraph nor $red is set within the scope of that function. You can either make them globals (which is a bad practice), or preferably pass those variable as parameters. Ex: <?php header("Content-type: image/png"); $timelineGraph = ImageCreate(300,300) or die("Cannot Initialize new GD image stream"); // Formatting $black = ImageColorAllocate($timelineGraph, 0, 0, 0); $red = ImageColorAllocate($timelineGraph, 255, 0, 0); function drawTimeline($im, $color, $startWeek, $startDay, $endWeek, $endDay) { ImageLine($im, 0, 0, 299, 299, $color); } drawTimeline($timelineGraph, $red, 1,1,1,1); ImagePng($timelineGraph); ImageDestroy($timelineGraph); ?> Link to comment https://forums.phpfreaks.com/topic/181229-strange-issue-with-custom-function-and-image-drawing/#findComment-956067 Share on other sites More sharing options...
patrick89 Posted November 12, 2009 Author Share Posted November 12, 2009 Thanks Alex, that's seemed to work! Though, even when I comment out the content-type header, I don't receive any errors? Whereabouts would I see the error? I'd assume it would be on the page in place of the image right? Link to comment https://forums.phpfreaks.com/topic/181229-strange-issue-with-custom-function-and-image-drawing/#findComment-956094 Share on other sites More sharing options...
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