标签：php7 size circle ttf === alter i++ exist 变量
画布：一种资源型数据，可以操作的图像资源。
输出到图片文件或直接输出（直接输出到浏览器）
注意：
如果没有第二个参数，表示直接输出。
如果直接输出到浏览器，需要告知浏览器响应数据的类型应该是XXX格式的图片：header(Content-Type: image/XXX)
一个画布可以输出多次，输出为各种格式
imageDestroy();
<?php
function create_captcha($data = ‘‘, $img_path = ‘‘, $img_url = ‘‘, $font_path = ‘‘){
$defaults = array(
‘word‘ => ‘‘,
‘img_path‘ => ‘‘,
‘img_url‘ => ‘‘,
‘img_width‘ => ‘150‘,
‘img_height‘ => ‘30‘,
‘font_path‘ => ‘‘,
‘expiration‘ => 7200,
‘word_length‘ => 4,
‘font_size‘ => 16,
‘img_id‘ => ‘‘,
‘pool‘ => ‘123456789abcdefghijklmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ‘,
‘colors‘ => array(
‘background‘ => array(255,255,255),
‘border‘ => array(153,102,102),
‘text‘ => array(204,153,153),
‘grid‘ => array(255,182,182)
)
);
// -----------------------------------
// 遍历defaults将每个下标创建出变量
// 如果参数$data中有这个下标则使用$date中的值作为该变量的值
// -----------------------------------
foreach ($defaults as $key => $val){
if ( ! is_array($data) && empty($$key))
{
$$key = $val;
}
else
{
$$key = isset($data[$key]) ? $data[$key] : $val;
}
}
// -----------------------------------
// 检测gd扩展是否加载
// -----------------------------------
if (! extension_loaded(‘gd‘)){
return FALSE;
}
// -----------------------------------
// Do we have a "word" yet?
// -----------------------------------
if (empty($word))
{
$word = ‘‘;
$pool_length = strlen($pool);
$rand_max = $pool_length - 1;
// PHP7 or a suitable polyfill
if (function_exists(‘random_int‘))
{
try
{
for ($i = 0; $i < $word_length; $i++)
{
$word .= $pool[random_int(0, $rand_max)];
}
}
catch (Exception $e)
{
// This means fallback to the next possible
// alternative to random_int()
$word = ‘‘;
}
}
}
if (empty($word))
{
for ($i = 0; $i < $word_length; $i++)
{
$word .= $pool[mt_rand(0, $rand_max)];
}
}
elseif ( ! is_string($word))
{
$word = (string) $word;
}
// -----------------------------------
// Determine angle and position（angle画字的时候用，x_axis和y_axis画圆的时候用）
// -----------------------------------
$length = strlen($word);
$angle = ($length >= 6) ? mt_rand(-($length-6), ($length-6)) : 0;
$x_axis = mt_rand(6, (360/$length)-16);
$y_axis = ($angle >= 0) ? mt_rand($img_height, $img_width) : mt_rand(6, $img_height);
// Create image
// PHP.net recommends imagecreatetruecolor(), but it isn‘t always available
$im = function_exists(‘imagecreatetruecolor‘)
? imagecreatetruecolor($img_width, $img_height)
: imagecreate($img_width, $img_height);
// -----------------------------------
// Assign colors
// ----------------------------------
is_array($colors) OR $colors = $defaults[‘colors‘];
foreach (array_keys($defaults[‘colors‘]) as $key)
{
// Check for a possible missing value
is_array($colors[$key]) OR $colors[$key] = $defaults[‘colors‘][$key];
/*
*‘background‘，‘border‘，‘text‘这三个颜色给画布，并放到$colors[$key]数组中。
*处理前$colors为
*array (size=4)
* ‘background‘ =>
* array (size=3)
* 0 => int 255
* 1 => int 255
* 2 => int 255
* ‘border‘ =>
* array (size=3)
* 0 => int 153
* 1 => int 102
* 2 => int 102
* ‘text‘ =>
* array (size=3)
* 0 => int 204
* 1 => int 153
* 2 => int 153
* ‘grid‘ =>
* array (size=3)
* 0 => int 255
* 1 => int 182
* 2 => int 182
*处理后$colors为
*array (size=4)
* ‘background‘ => int 16777215
* ‘border‘ => int 10053222
* ‘text‘ => int 13408665
* ‘grid‘ => int 16758454
*/
$colors[$key] = imagecolorallocate($im, $colors[$key][0], $colors[$key][1], $colors[$key][2]);
}
// Create the rectangle
ImageFilledRectangle($im, 0, 0, $img_width, $img_height, $colors[‘background‘]);
// -----------------------------------
// Create the spiral pattern（创建旋转图样）
// -----------------------------------
//theta：n. 希腊字母的第八字；时间递耗值
$theta = 1;
$thetac = 7;
//radius：半径
$radius = 16;
//circles：圆
$circles = 20;
//points：点
$points = 32;
/*这里没弄懂*/
for ($i = 0, $cp = ($circles * $points) - 1; $i < $cp; $i++)
{
$theta += $thetac;
$rad = $radius * ($i / $points);
$x = ($rad * cos($theta)) + $x_axis;
$y = ($rad * sin($theta)) + $y_axis;
$theta += $thetac;
$rad1 = $radius * (($i + 1) / $points);
$x1 = ($rad1 * cos($theta)) + $x_axis;
$y1 = ($rad1 * sin($theta)) + $y_axis;
imageline($im, $x, $y, $x1, $y1, $colors[‘grid‘]);
$theta -= $thetac;
}
// -----------------------------------
// Write the text（有字体和没字体分两种处理）
// -----------------------------------
$use_font = ($font_path !== ‘‘ && file_exists($font_path) && function_exists(‘imagettftext‘));
if ($use_font === FALSE)
{
($font_size > 5) && $font_size = 5;
$x = mt_rand(0, $img_width / ($length / 3));
$y = 0;
}
else
{
($font_size > 30) && $font_size = 30;
$x = mt_rand(0, $img_width / ($length / 1.5));
$y = $font_size + 2;
}
for ($i = 0; $i < $length; $i++)
{
if ($use_font === FALSE)
{
$y = mt_rand(0 , $img_height / 2);
imagestring($im, $font_size, $x, $y, $word[$i], $colors[‘text‘]);
$x += ($font_size * 2);
}
else
{
$y = mt_rand($img_height / 2, $img_height - 3);
imagettftext($im, $font_size, $angle, $x, $y, $colors[‘text‘], $font_path, $word[$i]);
$x += $font_size;
}
}
// Create the border
imagerectangle($im, 0, 0, $img_width - 1, $img_height - 1, $colors[‘border‘]);
// -----------------------------------
// Generate the image（生成图像）
// -----------------------------------
if (function_exists(‘imagejpeg‘))
{
header(‘Content-Type:image/jpeg‘);
imagejpeg($im);
}
elseif (function_exists(‘imagepng‘))
{
header(‘Content-Type:image/png‘);
imagepng($im);
}
else
{
return FALSE;
}
ImageDestroy($im);
return array(‘word‘ => $word);
}
create_captcha();验证码刷新：
onclick="this.src = ‘url?...&‘+Math.random()"标签：php7 size circle ttf === alter i++ exist 变量
原文地址：https://www.cnblogs.com/jffun-blog/p/10327434.html
