php - Getting imagegrabscreen to work

Question

I'm trying to get imagegrabscreen (a GD function) to work with my Apache/Vista PC.

I'm using the following code:

<?php
$im = imagegrabscreen();

header('Content-type: image/png');
imagepng($im);
imagedestroy($im);
?>

At the moment I get a solid black image, the size of my secondary monitor (1024*768). I'm using Apache 2.2, runing as a service, Vista SP1 with UAC off, PHP 5.2.8 and GD (information below). I've followed the note on the imagegrabscreen page about allowing Apache access to the desktop. I've also restarted the service and the apache server. I get the same results with imagegrabwindow.

Is this a bug (do other people have trouble running this method?) or is there something I'm doing wrong?

Array
(
    [GD Version] => bundled (2.0.34 compatible)
    [FreeType Support] => 1
    [FreeType Linkage] => with freetype
    [T1Lib Support] => 1
    [GIF Read Support] => 1
    [GIF Create Support] => 1
    [JPG Support] => 1
    [PNG Support] => 1
    [WBMP Support] => 1
    [XPM Support] => 
    [XBM Support] => 1
    [JIS-mapped Japanese Font Support] => 
)

Apache Service Log On details:

http://www.kalleload.net/uploads/maogfnfnczfh.png http://www.kalleload.net/uploads/maogfnfnczfh.png

Answer 1

I looked at the source to imagegrabscreen();

at this point, I believe it is failing because we both have multi-monitor set-ups.

The current code calls GetDC(0), which according to http://msdn.microsoft.com/en-us/library/dd144871(VS.85).aspx should return the device context for "the entire screen", but "To get the DC for a specific display monitor, use the EnumDisplayMonitors and CreateDC functions"

I am going to do a bit more testing of this and see if I can come up with multi-monitor-friendly code.