imagecropauto
Crop an image automatically using one of the available modes
Description
GdImagefalse imagecropauto(
GdImage $image,
int $mode = IMG_CROP_DEFAULT,
float $threshold = 0.5,
int $color = -1
)
Parameters
-
image
-
A GdImage object, returned by one of the image creation functions,
such as imagecreatetruecolor.
-
mode
-
One of the following constants:
-
IMG_CROP_DEFAULT
-
Same as
IMG_CROP_TRANSPARENT.
Before PHP 7.4.0, the bundled libgd fell back to IMG_CROP_SIDES,
if the image had no transparent color.
-
IMG_CROP_TRANSPARENT
-
Crops out a transparent background.
-
IMG_CROP_BLACK
-
Crops out a black background.
-
IMG_CROP_WHITE
-
Crops out a white background.
-
IMG_CROP_SIDES
-
Uses the 4 corners of the image to attempt to detect the background to
crop.
-
IMG_CROP_THRESHOLD
-
Crops an image using the given
threshold and
color.
-
threshold
-
Specifies the tolerance in percent to be used while comparing the image
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 results
for system and bundled libgd.
-
color
-
Either an RGB color value or a palette index.
Used only in IMG_CROP_THRESHOLD mode.
Return Values
Returns a cropped image object on success or false on failure.
false is also returned if the whole image was cropped.
Examples
Example #1 Proper handling of auto-cropping
As noted in the return value section, imagecropauto
returns false if the whole image
was cropped. In this example we have an image object
$im which should be automatically cropped only if there
is something to crop; otherwise we want to proceed with the original image.
<?php
$cropped = imagecropauto($im, IMG_CROP_DEFAULT);
if ($cropped !== false) { // in case a new image object was returned
imagedestroy($im); // we destroy the original image
$im = $cropped; // and assign the cropped image to $im
}
?>