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siushin2025-08-15
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3.5m

额外补充 ​

图片转ASCII码图 ​

php
function tochars($r, $g, $b, $px = 256, $char = "#ABCDEFGHIJKLMNOPQRSTUVWXYZ@$%??__ff--++~~''  ::..  ``  ")
{
    if ($px == 0)
        return '';
    $len = mb_strlen($char);
    //灰度值
    $gray = floor(($r + $g + $b) / 3);
    //将256个像素平均分配给字符
    $unit = ceil($px / $len);
    //获取当前像素对应的字符
    $index = floor($gray / $unit);
    if ($index >= $len) {
        $index = $len - 1;
    }
    return $char[(int)$index];
}

function tosmallim($const = 100, $width, $height, $image)
{
    if ($width > $const) {
        $times = floor($width / $const);
        $smwidth = $const;
        $smheight = floor($height / $times);
        $im = imagecreatetruecolor($smwidth, $smheight);
        imagecopyresampled($im, $image, 0, 0, 0, 0, $smwidth, $smheight, $width, $height);
        return [$im, $smwidth, $smheight];
    }
    return [$image, $width, $height];
}

$imname = 'http://s.siushin.com/siushin/upload/php/1901077809.png';

//返回一图像标识符，代表了从给定的文件名取得的图像
$image = ImageCreateFromPng($imname);
//$im = ImageCreateFromJpeg($imname);

$size = getimagesize($imname);
$width = $size[0];
$height = $size[1];

list($image, $width, $height) = tosmallim(100, $width, $height, $image);

$arr = [];
for ($i = 0; $i < $height; $i++) {
    for ($j = 0; $j < $width; $j++) {
        $rgb = ImageColorat($image, $j, $i);
        $r = ($rgb >> 16) & 0xFF;
        $g = ($rgb >> 8) & 0xFF;
        $b = $rgb & 0xFF;
        $arr[] = floor(($r + $g + $b) / 3);
    }
}
$num = count(array_unique($arr));
$str = '<span style="font-size: 8pt;
    letter-spacing: 4px;
    line-height: 8pt;
    font-weight: bold;display: block;
    font-family: monospace;
    white-space: pre;
    margin: 1em 0;">';
for ($i = 0; $i < $height; $i++) {
    for ($j = 0; $j < $width; $j++) {
        $rgb = ImageColorat($image, $j, $i);
        $r = ($rgb >> 16) & 0xFF;
        $g = ($rgb >> 8) & 0xFF;
        $b = $rgb & 0xFF;
        $str .= tochars($r, $g, $b, $num);
    }
    $str .= '<br>';
}
echo $str . '</span>';

生成指定数量的数字、字符串 ​

php
// 生成随机数
function randNumber($length = 4): string
{
    return join('', array_rand(range(0, 9), $length));
}

// 生成随机字符串
function randString($length = 4): string
{
    $stringList = array_flip(array_merge(range('a', 'z'), range('A', 'Z')));
    return join('', array_rand($stringList, $length));
}

// 生成随机数字+字符串
function randNumberAndString($length = 4): string
{
    $stringList = array_flip(array_merge(range(0, 9), range('a', 'z'), range('A', 'Z')));
    return join('', array_rand($stringList, $length));
}

单引号、双引号的区别 ​

双引号：解析所有转义符
单引号：只解析\\，\'这两个转义符

定界符(heredoc)、nowdoc ​

  • 定界符
php
$name = 'Hello World';
$eof = <<<EOF
$name
I'm a "true" \$man
EOF;

echo $eof;
// Hello World I'm a "true" $man
  • heredoc - 相当于双引号
php
$name = 'Hello World';
$heredoc = <<<"EOF"
$name
I'm a "true" \$man
EOF;

echo $heredoc;
// Hello World I'm a "true" $man
  • nowdoc - 不会解析任何转义符
php
$name = 'Hello World';
$nowdoc = <<<'EOF'
$name
I'm a "true" \$man
a\\b\\'c
EOF;

echo $nowdoc;
// $name I'm a "true" \$man a\\b\\'c

数值与字符串运算 ​

php
// 取合法数字，如果不是以合法数字开始，转换成0
echo 1 + '3abc';    // 3
// 8.1版本警告：Warning: A non-numeric value encountered in XXX on line 4

echo 1.2 + '4abc';  // 5.2
// 8.1版本警告：Warning: A non-numeric value encountered in XXX on line 6

echo 3 + '2e2';     // 203

echo 2 + 'true';    // 0（8.1版本报错，没有输出）
// 8.1版本报错：Fatal error: Uncaught TypeError: Unsupported operand types: int + string in XXX:12 Stack trace: #0 {main} thrown in
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