To clarify, for lines where the thickness is greater than 1, the total length of the $style array needs to be an exact divisor of the length of the line.
This is because the pattern is repeated lengthways and wraps onto the second row of pixels, causing staggering to occur.
So if you have 5 red and 5 white pixels, and you want a line length of 55 pixels, either change the length to a multiple of 10, or change the dashes to, say, 6 red and 5 white.
imagesetstyle
(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)
imagesetstyle — 设定画线的风格
说明
imagesetstyle
( resource
$image
, array $style
) : bool
imagesetstyle() 设定所有画线的函数（例如
imageline()
和 imagepolygon()）在使用特殊颜色
IMG_COLOR_STYLED 或者用
IMG_COLOR_STYLEDBRUSHED 画一行图像时所使用的风格。
参数
-
image -
由图象创建函数(例如imagecreatetruecolor())返回的图象资源。
-
style -
像素组成的数组。你可以通过常量
IMG_COLOR_TRANSPARENT来添加一个透明像素。
返回值
成功时返回 true， 或者在失败时返回 false。
范例
下面的示例脚本在画布上从左上角到右下角画一行虚线：
Example #1 imagesetstyle() 例子
<?php
header("Content-type: image/jpeg");
$im = imagecreatetruecolor(100, 100);
$w = imagecolorallocate($im, 255, 255, 255);
$red = imagecolorallocate($im, 255, 0, 0);
/* 画一条虚线，5 个红色像素，5 个白色像素 */
$style = array($red, $red, $red, $red, $red, $w, $w, $w, $w, $w);
imagesetstyle($im, $style);
imageline($im, 0, 0, 100, 100, IMG_COLOR_STYLED);
/* 用 imagesetbrush() 和 imagesetstyle 画一行笑脸 */
$style = array($w, $w, $w, $w, $w, $w, $w, $w, $w, $w, $w, $w, $red);
imagesetstyle($im, $style);
$brush = imagecreatefrompng("http://www.libpng.org/pub/png/images/smile.happy.png");
$w2 = imagecolorallocate($brush, 255, 255, 255);
imagecolortransparent($brush, $w2);
imagesetbrush($im, $brush);
imageline($im, 100, 0, 0, 100, IMG_COLOR_STYLEDBRUSHED);
imagejpeg($im);
imagedestroy($im);
?>
以上例程的输出类似于：
User Contributed Notes
dazbert
21-Mar-2017 05:26
Anonymous
22-Oct-2012 04:03
a shortcut for basic dashed lines, making it easy to adjust the lengths:
<?php
$length1 = 20;
$length2 = 10;
$style = array_merge(array_fill(0, $length1, $red), array_fill(0, $length2, $w));
imagesetstyle($im, $style);
?>
php at imperium dot be
06-Aug-2010 07:05
Be aware that styles are applied towards the width of the line instead of linear.
To convert a style to be used for thick lines you can use the function below:
<?php
/*
ImageStyleThicken(<aStyle>,<iThickness>) --> <aThickStyle>
<aStyle> is the style array for a thickness of 1 (see imagesetstyle()).
<iThickness> is the new thickness to apply (see imagesetthickness()).
<aThickStyle> is the style array suitable for the given thickness.
*/
function ImageStyleThicken($_1,$_2) {
$a = array();
foreach ($_1 as $x) {
$i = $_2;
do $a[] = $x; while (--$i>0); }
return $a;
}
?>
Wander
13-Dec-2007 11:12
Function to make a line with random fading:
<?php
function fading_line($img,$sx,$sy,$ex,$ey){
$r=rand(0,5);$g=rand(0,5);$b=rand(0,5);
$l=sqrt((($ex-$sx)*($ex-$sx))+(($ey-$sy)*($ey-$sy)));
for($i=0;$i<$l;$i++){
$a = array(255-((255/$l)*$i), 255,0,(255/$l)*$i/2,(255/$l)*$i,(255-((255/$l)*$i))/2);
$style[]=imagecolorallocate($img,$a[$r],$a[$g],$a[$b]);
}
imagesetstyle($img,$style);
imageline($img,$sx,$sy,$ex,$ey,IMG_COLOR_STYLED);
}
fading_line($img,10,20,490,40); // image, start x, start y, end x, end y
?>
Michael_Todd_335 at yahoo dot com
27-Jun-2007 09:40
Watch out! If you pass imagesetstyle() an empty array as the second argument, it will crash your server!
I was messing with it just earlier and accidentally did so, and the page took a good minute to process, when my Apache server came up with the good ol' Windows 'Send Error Report' window.
Cruz at FtUC dot net
15-Jan-2006 03:45
When lines drawn with imagesetstyle seem to produce a thin white line only, make sure antialiasing is disabled.
<?
imageantialias($im, false);
$style = array($gridxcolor, $gridxcolor, IMG_COLOR_TRANSPARENT, IMG_COLOR_TRANSPARENT);
imagesetstyle($im, $style);
imageline($im, $x, 0, $x, $ymax+5, IMG_COLOR_STYLED);
imageantialias($im, true);
?>
Setstyle and Antialias don't go together.
zackbloom at gmail dot com
06-Dec-2005 02:44
Use this to set the style to any combination of pixels.
You can pass as many modifiers as you wish.
Use the format [num]r[red]g[green]b[blue].
For example:
$im=dashed($im,"4r255g0b0","2r0g255b0","5r0g0b255");
imageline($im, 0, 0, 600, 600, IMG_COLOR_STYLED);
function dashed($im){
$size = func_num_args();
for($i = 0; $i < $size; $i++){
$arg = func_get_arg($i);
if(!is_resource($arg)){
$r=substr($arg,strpos($arg,"r")+1,
strpos($arg,"g")-strpos($arg,"r")-1);
$g=substr($arg,strpos($arg,"g")+1,
strpos($arg,"b")-strpos($arg,"g")-1);
$b=substr($arg,strpos($arg,"b")+1,
strlen($arg)-strpos($arg,"b"));
$color = imagecolorallocate($im,$r,$g,$b);
$x = substr($arg,0,strpos($arg,"r"));
$vals[$i] = array_fill(0,$x,$color);
}
}
for($k=0;$k<count($vals)+1;$k++)
if(array_key_exists($k,$vals)) $prop=array_merge($prop,$vals[$k]);
imagesetstyle($im, $prop);
return $im;
}