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Hello All,Ineed a help in uploading image in which i want that the image which is of 150 dpi(dots per inch ) ,is only upload and smaller den that show messge .My issuue is that how i apply tht :( please give me some direction in tht

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Last Post by neha05
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If you use Imagick, it has a method to determine resolution. Not sure if GD provides one. Otherwise there's still an option to read it directly from the file (saw an implementation on SO).

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thanks for quick reply but i am trying to use formula which dpi=(pixeles of lenght)/inches of lenght

pixles=width *height
and i am confusing in the inches of length is ?? or i am going in ryt direction ?

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Hi,

I think the OP wants to check if a given image matches the minimum print sizes at a defined DPI:

<?php

    $image = 'img1.jpg';

    list($w, $h) = getimagesize($image);

    $dpi = 150;

    # current sizes in inches
    $inW = round($w / $dpi, 2);
    $inH = round($h / $dpi, 2);

    # min print sizes in inches
    $printW = 5;
    $printH = 5;

    echo PHP_EOL;

    if($inW >= $printW && $inH >= $printH)
    {
        echo "Correct, the print sizes at {$dpi}DPI are: {$inW} x {$inH} inches";
    }
    else
    {
        echo "This image is too small";
    }

    echo PHP_EOL;

With an image at 1920x1080 the result will be 12.8x7.2 inches. You can get the same result with ImageMagick, as suggested by Pritaeas, for example from the command line:

identify -format "%[fx:w/150] by %[fx:h/150] inches" img1.jpg

Docs: http://www.imagemagick.org/script/identify.php

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thanks cereal ,but i am checking this code it echo same size 12.8x7.2 for any image "Correct, the print sizes at {$dpi}DPI are: {$inW} x {$inH} inches";

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