imagecropauto
Crop an image automatically using one of the available modes
Description
resource imagecropauto
( resource $image
[, int $mode = -1
[, float $threshold = .5
[, int $color = -1
]]] )
Parameters
-
image
-
An image resource, returned by one of the image creation functions,
such as imagecreatetruecolor.
-
mode
-
One of the following constants:
-
IMG_CROP_DEFAULT
-
Attempts to use
IMG_CROP_TRANSPARENT and if it
fails it falls back to IMG_CROP_SIDES.
-
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.
-
color
-
Either an RGB color value or a palette index.
Used only in IMG_CROP_THRESHOLD mode.
Return Values
Returns a cropped image resource on success or FALSE on failure.
If no cropping would occur, or the complete image would be cropped, that is
treated as failure, i.e. imagecrop returns FALSE.
Examples
Example #1 Proper handling of auto-cropping
As noted in the return value section, imagecropauto
returns FALSE when there is either nothing to crop or the whole image
would be cropped. In this example we have an image resource
$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 ($cropped !== false) { // in case a new image resource was returned
imagedestroy($im); // we destroy the original image
$im = $cropped; // and assign the cropped image to $im
}
?>