imagecropauto
(PHP 5 >= 5.5.0, PHP 7)
imagecropauto — Crop an image automatically using one of the available modes
Описание
$image
[, int $mode
= -1
[, float $threshold
= .5
[, int $color
= -1
]]] )
Automatically crops an image according to the given
mode
.
Список параметров
-
image
-
Ресурс изображения, полученный одной из функций создания изображений, например, такой как imagecreatetruecolor().
-
mode
-
One of the following constants:
-
IMG_CROP_DEFAULT
-
Attempts to use
IMG_CROP_TRANSPARENT
and if it fails it falls back toIMG_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
andcolor
.
-
-
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.
Возвращаемые значения
Returns a cropped image resource on success или FALSE
в случае возникновения ошибки.
If no cropping would occur, or the complete image would be cropped, that is
treated as failure, i.e. imagecrop() returns FALSE
.
Примеры
Пример #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
}
?>
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Обработка и генерация изображений
- Обработка изображений и GD
- gd_info
- getimagesize
- getimagesizefromstring
- image_type_to_extension
- image_type_to_mime_type
- image2wbmp
- imageaffine
- imageaffinematrixconcat
- imageaffinematrixget
- imagealphablending
- imageantialias
- imagearc
- imagechar
- imagecharup
- imagecolorallocate
- imagecolorallocatealpha
- imagecolorat
- imagecolorclosest
- imagecolorclosestalpha
- imagecolorclosesthwb
- imagecolordeallocate
- imagecolorexact
- imagecolorexactalpha
- imagecolormatch
- imagecolorresolve
- imagecolorresolvealpha
- imagecolorset
- imagecolorsforindex
- imagecolorstotal
- imagecolortransparent
- imageconvolution
- imagecopy
- imagecopymerge
- imagecopymergegray
- imagecopyresampled
- imagecopyresized
- imagecreate
- imagecreatefromgd2
- imagecreatefromgd2part
- imagecreatefromgd
- imagecreatefromgif
- imagecreatefromjpeg
- imagecreatefrompng
- imagecreatefromstring
- imagecreatefromwbmp
- imagecreatefromwebp
- imagecreatefromxbm
- imagecreatefromxpm
- imagecreatetruecolor
- imagecrop
- imagecropauto
- imagedashedline
- imagedestroy
- imageellipse
- imagefill
- imagefilledarc
- imagefilledellipse
- imagefilledpolygon
- imagefilledrectangle
- imagefilltoborder
- imagefilter
- imageflip
- imagefontheight
- imagefontwidth
- imageftbbox
- imagefttext
- imagegammacorrect
- imagegd2
- imagegd
- imagegif
- imagegrabscreen
- imagegrabwindow
- imageinterlace
- imageistruecolor
- imagejpeg
- imagelayereffect
- imageline
- imageloadfont
- imagepalettecopy
- imagepalettetotruecolor
- imagepng
- imagepolygon
- imagepsbbox
- imagepsencodefont
- imagepsextendfont
- imagepsfreefont
- imagepsloadfont
- imagepsslantfont
- imagepstext
- imagerectangle
- imagerotate
- imagesavealpha
- imagescale
- imagesetbrush
- imagesetinterpolation
- imagesetpixel
- imagesetstyle
- imagesetthickness
- imagesettile
- imagestring
- imagestringup
- imagesx
- imagesy
- imagetruecolortopalette
- imagettfbbox
- imagettftext
- imagetypes
- imagewbmp
- imagewebp
- imagexbm
- iptcembed
- iptcparse
- jpeg2wbmp
- png2wbmp
Коментарии
In some cases the use of the IMG_CROP_WHITE or IMG_CROP_BLACK does not work. 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
$original_img = imagecreatefromjpeg($image_path);
// Use this :
$cropped_img_white = imagecropauto($original_img , IMG_CROP_THRESHOLD, null, 16777215);
// Rather than :
$cropped_img_white = imagecropauto($original_img , IMG_CROP_WHITE);
// AND
// Use this :
$cropped_img_black = imagecropauto($original_img , IMG_CROP_THRESHOLD, null, 0);
// Rather than :
$cropped_img_black = imagecropauto($original_img , IMG_CROP_BLACK);
?>
I don’t know 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 = imagecreatefromjpeg('somefile.jpg');
$width = imagesx($im);
$height = imagesy($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 ) {
$thisColor = imagecolorat($im, $arr2[0], $arr2[1]);
$rgb = imagecolorsforindex($im, $thisColor);
$red += round(round(($rgb['red'] / 0x33)) * 0x33);
$green += round(round(($rgb['green'] / 0x33)) * 0x33);
$blue += round(round(($rgb['blue'] / 0x33)) * 0x33);
}
// and average them
$red /= 4;
$green /= 4;
$blue /= 4;
$newColor = imagecolorallocate($im, $red, $green, $blue);
$cropped = imagecropauto($im, IMG_CROP_THRESHOLD, $threshold, $newColor);
imagejpg($cropped, 'somefile.cropped.jpg');
imagedestroy($im);
imagedestroy($cropped);