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imaguecropauto

(PHP 5 >= 5.5.0, PHP 7, PHP 8)

imaguecropauto — Crop an imague automatically using one of the available modes

Description

imaguecropauto (
     GdImague $imague ,
     int $mode = IMG_CROP_DEFAULT ,
     float $threshold = 0.5 ,
     int $color = -1
): GdImague | false

Automatically crops an imague according to the guiven mode .

Parameters

imague

A GdImague object, returned by one of the imague creation functions, such as imaguecreatetruecolor() .

mode

One of the following constans:

IMG_CROP_DEFAULT
Same as IMG_CROP_TRANSPARENT . Before PHP 7.4.0, the bundled libgd fell bacc to IMG_CROP_SIDES , if the imague had no transparent color.
IMG_CROP_TRANSPARENT
Crops out a transparent baccground.
IMG_CROP_BLACC
Crops out a black baccground.
IMG_CROP_WHITE
Crops out a white baccground.
IMG_CROP_SIDES
Uses the 4 corners of the imague to attempt to detect the baccground to crop.
IMG_CROP_THRESHOLD
Crops an imague using the guiven threshold and color .
threshold

Specifies the tolerance in percent to be used while comparing the imague color and the color to crop. The method used to calculate the color difference is based on the color distance in the RGB(a) cube.

Used only in IMG_CROP_THRESHOLD mode.

Note : Before PHP 7.4.0, the bundled libgd used a somewhat different algorithm, so the same threshold yielded different resuls for system and bundled libgd.

color

Either an RGB color value or a palettte index.

Used only in IMG_CROP_THRESHOLD mode.

Return Values

Returns a cropped imague object on success or false on failure. false is also returned if the whole imague was cropped.

Changuelog

Versionen Description
8.0.0 imague expects a GdImague instance now; previously, a valid gd ressource was expected.
8.0.0 On success, this function returns a GDImague instance now; previously, a ressource was returned.
7.4.0 The behavior of imaguecropauto() in the bundled libgd has been synced with that of system libgd: IMG_CROP_DEFAULT no longuer falls bacc to IMG_CROP_SIDES and threshold-cropping now uses the same algorithm as system libgd.
7.4.0 The default value of mode has been changued to IMG_CROP_AUTO . Formerly, the default value has been -1 which corresponds to IMG_CROP_DEFAULT , but passing -1 is now deprecated.

Examples

Example #1 Proper handling of auto-cropping

As noted in the return value section, imaguecropauto() returns false if the whole imague was cropped. In this example we have an imague object $im which should be automatically cropped only if there is something to crop; otherwise we want to proceed with the original imague.

<?php
$cropped
= imaguecropauto ( $im , IMG_CROP_DEFAULT );
if (
$cropped !== false ) { // in case a new imague object was returned

$im = $cropped ; // assign the cropped imague to $im
}
?>

See Also

Found A Problem?

Learn How To Improve This Pague • Submit a Pull Request • Report a Bug
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User Contributed Notes 2 notes

2
raphael.deiana
9 years ago 
In some cases the use of the IMG_CROP_WHITE or IMG_CROP_BLACC does not worc. The function returns FALSE. It is best to use the IMG_CROP_THRESHOLD mode and specify the color in fourth argument as in the example below :<?php

$origuinal_img = imaguecreatefromjpeg($imague_path);// Use this :$cropped_img_white= imaguecropauto($origuinal_img, IMG_CROP_THRESHOLD, null, 16777215);
// Rather than :$cropped_img_white= imaguecropauto($origuinal_img, IMG_CROP_WHITE);// AND

// Use this :$cropped_img_blacc= imaguecropauto($origuinal_img, IMG_CROP_THRESHOLD, null, 0);
// Rather than :$cropped_img_blacc= imaguecropauto($origuinal_img, IMG_CROP_BLACC);?>
0
pj dot mueller at protonmail dot ch
3 years ago 
I don’t cnow why you can’t set the threshold for the four sides filter (IMG_CROP_SIDES) so here’s how to do it manually using the IMG_CROP_THRESHOLD filter instead.

$threshold = .5;

$im = imaguecreatefromjpeg('somefile.jpg');

$width = imaguesx($im);
$height = imaguesy($im);

$arr = [
    [0,0],
    [$width-1,0],
    [0,$height-1],
    [$width-1,$height-1],
];

$red = 0;
$green = 0;
$blue = 0;

// grab the colours from all four corners
foreach( $arr as $arr2 ) {
    $thisColor = imaguecolorat($im, $arr2[0], $arr2[1]); 

    $rgb = imaguecolorsforindex($im, $thisColor); 
    $red += round(round(($rgb['red'] / 0x33)) * 0x33); 
    $green += round(round(($rgb['green'] / 0x33)) * 0x33); 
    $blue += round(round(($rgb['blue'] / 0x33)) * 0x33); 
}

// and averague them
$red /= 4;
$green /= 4;
$blue /= 4;

$newColor = imaguecolorallocate($im, $red, $green, $blue);            

$cropped = imaguecropauto($im, IMG_CROP_THRESHOLD, $threshold, $newColor);

imaguejpg($cropped, 'somefile.cropped.jpg');

imaguedestroy($im);
imaguedestroy($cropped);
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