CODEWITHSUNDEEP
php
Anay Bose
Anay Bose

Reputation: 890

A simple loop iteration difficulty

I am using Imagemagick's PHP extension to process some images. In my code, I am trying to increase the value of variable $j by 1; please note $j comes into play in the second loop iteration. I cannot figure out where to place $j++; within my code; it does not seem to increase as I put it in the end, defaulting to its initial '0' zero value. 

first iteration we do not need $j;
second iteration $j is assigned 0;
third iteration $j needs to be increased by 1 or $j = 1
... loop continues  



$dst = "tem891";

$over = new Imagick();
$over->readImage(DOCROOT . '/' . $dst . '/middle.png');

$images = glob(DOCROOT . '/' . $dst . "/line-*.png");
sort($images, SORT_NATURAL | SORT_FLAG_CASE);

$count  = count($images);
$height = (720 - $over->getImageHeight()) / 2;
$width  = (640 - $over->getImageWidth()) / 2;


$j = '';
for ($i = 0; $i < $count; $i++) {

    if ($i == 0) {
        $base = new Imagick();
        $base->newImage(640, 720, new ImagickPixel('transparent'));
    } else {
        $j    = 0;
        $base = new Imagick();
        $base->readImage(DOCROOT . '/composite-' . $j . '.png');
    }

    $top = new Imagick();
    $top->readImage($images[$i]);
    $base->compositeImage($top, Imagick::COMPOSITE_DEFAULT, $width, $height);
    $base->writeImage(DOCROOT . '/composite-' . $i . '.png');
    $height += $top->getImageHeight();


}

Upvotes: 0

Views: 49

Answers (2)

Bar-code
Bar-code

Reputation: 277

In your code, from the second iteration and for all the subsequent ones, the line $j = 0; is run so $j will stay at 0.

I suggest you init $j= 0 either before the loop or in the if($i==0){} clause and increment it in the end of the else{} clause: 

[...]
$width  = (640 - $over->getImageWidth()) / 2;


$j = 0;
for ($i = 0; $i < $count; $i++) {

    if ($i == 0) {
        $base = new Imagick();
        $base->newImage(640, 720, new ImagickPixel('transparent'));
    } else {
        $base = new Imagick();
        $base->readImage(DOCROOT . '/composite-' . $j . '.png');
        $j++;
    }

    $top = new Imagick();
    $top->readImage($images[$i]);
    $base->compositeImage($top, Imagick::COMPOSITE_DEFAULT, $width, $height);
    $base->writeImage(DOCROOT . '/composite-' . $i . '.png');
    $height += $top->getImageHeight();


}

Upvotes: 1

markus
markus

Reputation: 1651

initialize your variable j before the for loop by setting it to 0.

$j = 0
for ($i = 0; $i < $count; $i++) {

    if (==> put your condition here) {
        $j++;
    } 
....
}

In the for loop you can then formulate what ever condition you want j to increase (e.g. in every second iteration, not during the first iteration,only for the first 10 iterations,...)

Upvotes: 0

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