[RESOLVED] ImageMagick Help

Shawazi

I've finally installed imageMagick.

//function declaration and some variables defined
//......
$resource = NewMagickWand(); //create wand
MagickReadImage( $resource, $from ); //read source image
echo var_dump($resource)."<br />";
$resource = MagickTransformImage( $resource, '0x0', $dest_x.'x'.$dest_y ); //resize image
MagickWriteImage($resource, $to);  //save resized image
DestroyMagickWand($resource); //destroy wand

$resource = NewMagickWand(); //create wand
MagickReadImage( $resource, $to ); //read source image
echo var_dump($resource)."<br />";
exit;
return $resource;

It prints out this:

resource(22) of type (MagickWand resource)
resource(24) of type (MagickWand resource)

Why doesn't it go back to 22? What I'm really trying to accomplish is to modify an image and then return the resource to use in another function. This way I can use my resize function, get the $resource, and use my crop function on the resized image later.

bpat1434

Because each new instantiation of an object creates a new object. Basically, you're creating two MagickWand objects, and even though they're related in your mind, they're not in PHP's.

If you want to return the objects of the original and the transformed, you'd be better off using something like:

$original = NewMagickWand();
MagickReadImage($original, $from);

$transformed = MagickTransformImage($original, '0x0', $dest_x.'x'.$dest_y);
MagickWriteImage($transformed, $to);
DestroyMagickWand($transformed);

return $original;

No need to create three objects when you can use two.

Shawazi

This helps me understand imageMagick some more, but does not tackle exactly what I wanted. I want to now be able to transform the resized image. I am going to assume and try doing return $transformed so my crop function can now crop it.

Shawazi

This function works perfect.

/*******
Make thumbnail based on width
twidth: the width
from_dir: where to pull original from
to_dir: where to save resized image to
name: name of file
prefix: (optional) add a prefix to file name so 'temp_image.jpg' instead of 'image.jpg'
resource: (optional) the resource of a previously modified image to use instead of from_dir
*******/
function make_thumb ($twidth, $from_dir, $to_dir, $name, $prefix='', $source='')
{
	$from = $from_dir.$name; //path of source image
	$to = $to_dir.$prefix.$name; //path of destination

$size = GetImageSize($from); //size of source
$dest = getHorizontalProp($size, $twidth);  //returns array of new dimensions
$dest_x = $dest['x'];
$dest_y = $dest['y'];

if ($resource != 0) {
	$original = $resource;
} else {
	$original = NewMagickWand() or die("Unable to create wand (MT)"); //create wand
	MagickReadImage( $original, $from ) or die("Unable to ead source image (MT)"); //read source image
}
$transSize = MagickTransformImage( $original, '0x0', $dest_x.'x'.$dest_y ) or die("Unable to resize image (MT)"); //resize image
MagickWriteImage($transSize, $to) or die("Unable to save resized image (MT)");  //save resized image
DestroyMagickWand($transSize) or die("Unable to destroy wand (MT)"); //destroy wand

return $transSize;
}

I don't know how I am returning $transSize after destroying the wand, but I can use the returned value to resize an image over and over again.

//source_id_original is defined above
make_thumb (200, $directory, $directory, $main, 'test_', $source_id_original); // this works

MagickCropImage( $source_id_original, $box_width, $box_height, $width_in, $height_in ); //this does not work (dimensions of crop also defined elsewhere)

Shawazi

I got rid of the destroy line and it works. Why would it work resizing repeatedly? That is the part that still makes no sense.

Weedpacket

Shawazi wrote:
I don't know how I am returning $transSize after destroying the wand, but I can use the returned value to resize an image over and over again.

But you're not using the returned value. You're not even keeping it
after it has been returned. Where in your second piece of code are you using the return value from make_thumb()? You're not, you're just calling make_thumb(). If you had written

$size = make_thumb(....);
do_something_with($size);

then you'd be using the returned value. But you're not.

I got rid of the destroy line and it works. Why would it work resizing repeatedly? That is the part that still makes no sense.

The bit that doesn't make sense to me is why in the first place you wanted to destroy something you wanted to reuse.

Shawazi

It was a mistake as I was trying to learn this. I had trouble finding good tutorials online for PHP. I just bought two books and should be imageMagicked up soon 🙂