imagecolorallocatealpha
(PHP 4 >= 4.3.2, PHP 5, PHP 7)
imagecolorallocatealpha — 为一锟斤拷图锟斤拷锟斤拷锟斤拷锟缴� + alpha
说锟斤拷
$image
, int $red
, int $green
, int $blue
, int $alpha
) : int
imagecolorallocatealpha() 锟斤拷锟斤拷为锟斤拷
imagecolorallocate() 锟斤拷同锟斤拷锟斤拷锟斤拷锟斤拷一锟斤拷锟斤拷锟斤拷锟酵革拷锟斤拷炔锟斤拷锟�
alpha锟斤拷锟斤拷值锟斤拷
0 锟斤拷 127锟斤拷0
锟斤拷示锟斤拷全锟斤拷透锟斤拷锟斤拷127 锟斤拷示锟斤拷全透锟斤拷锟斤拷
锟斤拷锟斤拷锟斤拷锟绞э拷锟斤拷蚍祷锟� FALSE锟斤拷
Example #1 使锟斤拷 imagecolorallocatealpha() 锟斤拷锟斤拷锟斤拷
<?php
$size = 300;
$image=imagecreatetruecolor($size, $size);
// 锟矫帮拷色锟斤拷锟斤拷锟接猴拷色锟竭框画革拷锟斤拷锟斤拷
$back = imagecolorallocate($image, 255, 255, 255);
$border = imagecolorallocate($image, 0, 0, 0);
imagefilledrectangle($image, 0, 0, $size - 1, $size - 1, $back);
imagerectangle($image, 0, 0, $size - 1, $size - 1, $border);
$yellow_x = 100;
$yellow_y = 75;
$red_x = 120;
$red_y = 165;
$blue_x = 187;
$blue_y = 125;
$radius = 150;
// 锟斤拷 alpha 值锟斤拷锟斤拷一些锟斤拷色
$yellow = imagecolorallocatealpha($image, 255, 255, 0, 75);
$red = imagecolorallocatealpha($image, 255, 0, 0, 75);
$blue = imagecolorallocatealpha($image, 0, 0, 255, 75);
// 锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷圆
imagefilledellipse($image, $yellow_x, $yellow_y, $radius, $radius, $yellow);
imagefilledellipse($image, $red_x, $red_y, $radius, $radius, $red);
imagefilledellipse($image, $blue_x, $blue_y, $radius, $radius, $blue);
// 锟斤拷要锟斤拷锟斤拷锟斤拷锟斤拷锟饺凤拷锟� header锟斤拷
header('Content-type: image/png');
// 锟斤拷锟斤拷锟斤拷锟斤拷锟�
imagepng($image);
imagedestroy($image);
?>
Note: 锟剿猴拷锟斤拷锟斤拷要 GD 2.0.1 锟斤拷锟斤拷甙姹�(锟狡硷拷 2.0.28 锟斤拷锟斤拷锟竭版本)锟斤拷
锟轿硷拷 imagecolorallocate() 锟斤拷 imagecolordeallocate()锟斤拷
锟斤拷锟斤拷
-
image -
锟斤拷图锟襟创斤拷锟斤拷锟斤拷(锟斤拷锟斤拷imagecreatetruecolor())锟斤拷锟截碉拷图锟斤拷锟斤拷源锟斤拷
-
red -
锟斤拷色锟缴分碉拷值锟斤拷
-
green -
锟斤拷色锟缴分碉拷值锟斤拷
-
blue -
锟斤拷色锟缴分碉拷值锟斤拷
-
alpha -
A value between 0 and 127. 0 indicates completely opaque while 127 indicates completely transparent.
锟斤拷锟斤拷值
A color identifier or FALSE if the allocation failed.
锟剿猴拷锟斤拷锟斤拷锟杰凤拷锟截诧拷锟斤拷值
FALSE锟斤拷锟斤拷也锟斤拷锟杰凤拷锟截碉拷同锟斤拷 FALSE 锟侥非诧拷锟斤拷值锟斤拷锟斤拷锟侥讹拷 锟斤拷锟斤拷锟斤拷锟斤拷锟铰斤拷锟皆伙拷取锟斤拷锟斤拷锟斤拷息锟斤拷应使锟斤拷
===
锟斤拷锟斤拷锟�锟斤拷锟斤拷锟皆此猴拷锟斤拷锟侥凤拷锟斤拷值锟斤拷
锟斤拷锟斤拷锟斤拷志
| 锟芥本 | 说锟斤拷 |
|---|---|
| Prior to 5.1.3 | Returns -1 if the allocation failed. |
锟斤拷锟斤拷
Example #2 Example of using imagecolorallocatealpha()
<?php
$size = 300;
$image=imagecreatetruecolor($size, $size);
// something to get a white background with black border
$back = imagecolorallocate($image, 255, 255, 255);
$border = imagecolorallocate($image, 0, 0, 0);
imagefilledrectangle($image, 0, 0, $size - 1, $size - 1, $back);
imagerectangle($image, 0, 0, $size - 1, $size - 1, $border);
$yellow_x = 100;
$yellow_y = 75;
$red_x = 120;
$red_y = 165;
$blue_x = 187;
$blue_y = 125;
$radius = 150;
// allocate colors with alpha values
$yellow = imagecolorallocatealpha($image, 255, 255, 0, 75);
$red = imagecolorallocatealpha($image, 255, 0, 0, 75);
$blue = imagecolorallocatealpha($image, 0, 0, 255, 75);
// drawing 3 overlapped circle
imagefilledellipse($image, $yellow_x, $yellow_y, $radius, $radius, $yellow);
imagefilledellipse($image, $red_x, $red_y, $radius, $radius, $red);
imagefilledellipse($image, $blue_x, $blue_y, $radius, $radius, $blue);
// don't forget to output a correct header!
header('Content-Type: image/png');
// and finally, output the result
imagepng($image);
imagedestroy($image);
?>
锟斤拷锟斤拷锟斤拷锟教碉拷锟斤拷锟斤拷锟斤拷锟斤拷冢锟�
注锟斤拷
Note: 锟剿猴拷锟斤拷锟斤拷要 GD 2.0.1 锟斤拷锟斤拷甙姹�(锟狡硷拷 2.0.28 锟斤拷锟斤拷锟竭版本)锟斤拷