Create fixed thumbnail dimensions for images with different sizes - php

Question

I just want to know if it is possible to get different images' sizes, and create fixed thumbnail dimension measurements for these pictures without losing their accurate aspect ratios.
So far, I have made these:
Resize different images
Maintain their aspect ratios
NOT supplying the same size (for example: 100px- height and 100px- width)
Here's the code that I am working with:
<?php
require("dbinfo.php");
$allPhotosQuery = mysql_query (" SELECT * FROM `placesImages` ");
while ($allPhotosArray = mysql_fetch_assoc ($allPhotosQuery))
{
$filename= $allPhotosArray['fileName'];
$placeId = $allPhotosArray['placeId'];
$imagePath = "placesImages/" . $placeId . "/" . $filename;
$imageSize = getimagesize($imagePath);
$imageWidth = $imageSize[0];
$imageHeight = $imageSize[1];
$newSize = ($imageWidth + $imageHeight)/($imageWidth*($imageHeight/45));
$newHeight = $imageHeight * $newSize;
$newWidth = $imageWidth * $newSize;
echo "<img src='".$imagePath."' width='".$newWidth."' height='".$newHeight."' />";
}
?>

Answer 1

Short of cropping, the simplest way to maintain aspect ratio while making a thumbnail is to do something similar to what you have, but set one fixed:
For example, if you want all your tumbs to be 100px wide:
$imageWidth = $imageSize[0];
$imageHeight = $imageSize[1];
$ratio=ImageWidth/$imageHeight;
$newHeight=(int)$ratio*100;
$newWidth=100;
The caveat with this is that you might end up with some funny sizes if the image has a funny ratio - as in it will happily go ahead and just do it. It might be a good idea to put some sort of check on the ratio in your code - if it it too low or too high, do something else, otherwise use this standard process.

Answer 2

feed this function your original image width and heights followed by the maximum constraints of your thumbnail limits and it will spit out an array with x/y of what you should set your thumbnail at to maintain aspect ratio. (anything smaller than the thumbnail will be enlarged)
function imageResizeDimensions($source_width,$source_height,$thumb_width,$thumb_height)
{
$source_ratio = $source_width / $source_height;
$thumb_ratio = $thumb_width / $thumb_height;
if($thumb_ratio > $source_ratio)
{
return array('x'=>$thumb_height * $source_ratio,'y'=>$thumb_height);
}
elseif($thumb_ratio < $source_ratio)
{
return array('x'=>$thumb_width,'y'=>$thumb_width/$source_ratio);
}
else
{
return array('x'=>$thumb_width,'y'=>$thumb_width);
}
}

Answer 3

Let’s begin with two constants, thumb_width and thumb_height, which are the desired width and height of your thumbnail images. They can be equal, but don’t have to be.
If you have an image that’s wider than it is tall (landscape) we can set the width to the desired width of the thumbnail, thumb_width, and adjust the height to maintain the aspect ratio.
new_width = thumb_width
new_height = thumb_height * old_height / old_width
See imagecreatetruecolor.
Then you can move the image to center it vertically within the limits of the thumbnail, producing a letterbox effect. See imagecopyresampled.
new_y = (thumb_height - new_height) / 2
For images that are taller than they are wide (portrait) the procedure is the same, but the math is a little different.
new_height = thumb_height
new_width = thumb_width * old_width / old_height
Then you can center it horizontally within the limits of the thumbnail.
new_x = (thumb_width - new_width) / 2
For more information on the basics of creating thumbnail images see Resizing images in PHP with GD and Imagick