imagecropauto
(PHP 5 >= 5.5.0, PHP 7, PHP 8)
imagecropauto — Crop an image automatically using one of the available modes
說明
GdImage
$image,int
$mode = IMG_CROP_DEFAULT,float
$threshold = 0.5,int
$color = -1): GdImage|false
Automatically crops an image according to the given
mode.
參數
-
image -
由圖像建立函式(例如imagecreatetruecolor())返回的 GdImage 對象。
-
mode -
One of the following constants:
-
IMG_CROP_DEFAULT -
Same as
IMG_CROP_TRANSPARENT. Before PHP 7.4.0, the bundled libgd fell back toIMG_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
thresholdandcolor.
-
-
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_THRESHOLDmode.注意: Before PHP 7.4.0, the bundled libgd used a somewhat different algorithm, so the same
thresholdyielded different results for system and bundled libgd. -
color -
Either an RGB color value or a palette index.
Used only in
IMG_CROP_THRESHOLDmode.
返回值
Returns a cropped image object on success 或者在失敗時返回 false.
If the complete image was cropped, imagecrop() returns false.
更新日誌
| 版本 | 說明 |
|---|---|
| 8.0.0 |
image expects a GdImage
instance now; previously, a resource was expected.
|
| 8.0.0 | On success, this function returns a GDImage instance now; previously, a resource was returned. |
| 7.4.0 |
The behavior of imagecropauto() in the bundled libgd has been synced with
that of system libgd: IMG_CROP_DEFAULT no longer falls
back 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 changed to
IMG_CROP_AUTO. Formerly, the default value has been
-1 which corresponds to IMG_CROP_DEFAULT,
but passing -1 is now deprecated.
|
範例
示例 #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
}
?>
參見
- imagecrop() - Crop an image to the given rectangle