(PHP 4, PHP 5)
imagestringup — 垂直地画一行字符串
$image
, int $font
, int $x
, int $y
, string $s
, int $col
)
imagestring() 用 col
颜色将字符串 s 垂直地画到 image
所代表的图像的 x, y
座标处（图像的左上角为 0, 0）。如果 font
是 1，2，3，4 或 5，则使用内置字体。
参见 imageloadfont()。
(2002-12-13 05:19:22)
function imagestringdown(&$image, $font, $x, $y, $s, $col)
{
$width = imagesx($image);
$height = imagesy($image);
$text_image = imagecreate($width, $height);
$white = imagecolorallocate ($text_image, 255, 255, 255);
$black = imagecolorallocate ($text_image, 0, 0, 0);
$transparent_colour = $white;
if ($col == $white)
$transparent_color = $black;
imagefill($text_image, $width, $height, $transparent_colour);
imagecolortransparent($text_image, $transparent_colour);
imagestringup($text_image, $font, ($width - $x), ($height - $y), $s, $col);
imagerotate($text_image, 180.0, $transparent_colour);
imagecopy($image, $text_image, 0, 0, 0, 0, $width, $height);
}