GD 和图像处理 函数
PHP Manual

imagecropauto

(PHP 5 >= 5.5.0, PHP 7)

imagecropautoCrop an image automatically using one of the available modes

说明

resource imagecropauto ( resource $image [, int $mode = -1 [, float $threshold = .5 [, int $color = -1 ]]] )

Automatically crops an image according to the given mode.

参数

image

由图象创建函数(例如imagecreatetruecolor())返回的图象资源。

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.

返回值

Returns a cropped image resource on success 或者在失败时返回 FALSE. If no cropping would occur, or the complete image would be cropped, that is treated as failure, i.e. imagecrop() returns FALSE.

范例

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
$cropped 
imagecropauto($imIMG_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
}
?>

参见


GD 和图像处理 函数
PHP Manual