PHP Intervention Image Resize image to fit shortest side to aspect ratio

image processingimage resizingPHP

How do I resize an image using Intervention Image maintaining the aspect ratio but making the image's shortest side fit the desired resize ratio.

E.g. a 800×400 image resized to fit 100×100 will be resized to 200×100

I tried this:

$image->resize($width, $height, function ($constraint) {
    $constraint->aspectRatio();
});

But it resizes the longest side to fit (e.g. 100×50).

Best Answer

Set width as null :

$height = 100;
$image = Image::make('800x400.jpg')->resize(null, $height, function ($constraint) {
    $constraint->aspectRatio();
});
$image->save('200X100.jpg', 60);

Programatically speaking, just find which side is larger and set it to null, i.e:

$width = 100;
$height = 100;
$image = Image::make('400x800.png');
$image->width() > $image->height() ? $width=null : $height=null;
$image->resize($width, $height, function ($constraint) {
    $constraint->aspectRatio();
});
$image->save('100x200.jpg', 60);

Related Solutions

C# – Resize Image to fit in bounding box

Find which is smaller: MaxWidth / w or MaxHeight / h Then multiply w and h by that number

Explanation:

You need to find the scaling factor which makes the image fit.

To find the scaling factor, s, for the width, then s must be such that: s * w = MaxWidth. Therefore, the scaling factor is MaxWidth / w.

Similarly for height.

The one that requires the most scaling (smaller s) is the factor by which you must scale the whole image.

Php – Calculating image size ratio for resizing

Here's code from my personal grab bag of image resizing code. First, data you need:

list($originalWidth, $originalHeight) = getimagesize($imageFile);
$ratio = $originalWidth / $originalHeight;

Then, this algorithm fits the image into the target size as best it can, keeping the original aspect ratio, not stretching the image larger than the original:

$targetWidth = $targetHeight = min($size, max($originalWidth, $originalHeight));

if ($ratio < 1) {
    $targetWidth = $targetHeight * $ratio;
} else {
    $targetHeight = $targetWidth / $ratio;
}

$srcWidth = $originalWidth;
$srcHeight = $originalHeight;
$srcX = $srcY = 0;

This crops the image to fill the target size completely, not stretching it:

$targetWidth = $targetHeight = min($originalWidth, $originalHeight, $size);

if ($ratio < 1) {
    $srcX = 0;
    $srcY = ($originalHeight / 2) - ($originalWidth / 2);
    $srcWidth = $srcHeight = $originalWidth;
} else {
    $srcY = 0;
    $srcX = ($originalWidth / 2) - ($originalHeight / 2);
    $srcWidth = $srcHeight = $originalHeight;
}

And this does the actual resizing:

$targetImage = imagecreatetruecolor($targetWidth, $targetHeight);
imagecopyresampled($targetImage, $originalImage, 0, 0, $srcX, $srcY, $targetWidth, $targetHeight, $srcWidth, $srcHeight);

In this case the $size is just one number for both width and height (square target size). I'm sure you can modify it to use non-square targets. It should also give you an inspiration on what other resizing algorithms you can use.

Best Answer

Related Solutions

C# – Resize Image to fit in bounding box

Php – Calculating image size ratio for resizing

Related Topic