php - 当我尝试在 PHP + GD 库中添加图像时，文本消失了

Question

我正在尝试创建一个带有一些文本和缩放图片的 PNG。这是文本的代码，它工作正常：

<?php
session_start();
error_reporting(E_ALL);

$label = imagecreate(500, 500);
imagecolorallocate($label, 0, 0, 0);

// up text
$color = imagecolorallocate($label, 255, 255, 255);
imagettftext($label, 50, 0, 0, 150, $color, "arial.ttf", "UP UP UP");

// down text
$color = imagecolorallocate($label, 255, 255, 255);
imagettftext($label, 50, 0, 0, 350, $color, "assets/fonts/arial.ttf", "DOWN DOWN DOWN");

header('Content-type: image/png');
imagepng($label);
imagedestroy($label);
die();
?>

使用上面的代码，您会得到以下图片，这是正确的：

现在我想在里面放一张小图片，所以我从 JPEG 文件 (adidas.jpg) 加载图片。这是代码

<?php
session_start();
error_reporting(E_ALL);


$label = imagecreate(500, 500);
imagecolorallocate($label, 0, 0, 0);


// up text
$color = imagecolorallocate($label, 255, 255, 255);
imagettftext($label, 50, 0, 0, 150, $color, "arial.ttf", "UP UP UP");

// image
$src = imagecreatefromjpeg("adidas.jpg");
$pic = imagecreatetruecolor(500, 500);
imagecopyresampled($label, $src, 0, 0, 0, 0, 150, 150, imagesx($src), imagesy($src));
$white = imagecolorallocate($pic, 255, 255, 255);
imagefill($label,0,0,$white);
imagedestroy($pic);


// down text
$color = imagecolorallocate($label, 255, 255, 255);
imagettftext($label, 50, 0, 0, 350, $color, "arial.ttf", "DOWN DOWN DOWN");

header('Content-type: image/png');
imagepng($label);
imagedestroy($label);
die();
?>

这就是我得到的：

令我惊讶的是，“向下”文本消失了。这是为什么？图片前加的文字没问题，后加的文字不知为何变黑了

Answer 1

您的代码有点乱，如果您删除第二个，则会出现“DOWN..”文本：

$color = imagecolorallocate($label, 255, 255, 255);

您不填充原始图像，稍后尝试但颜色错误（$white 来自 $pic，而不是 $label）。我清理了它：

<?php
session_start();
error_reporting(E_ALL);

$label = imagecreate(500, 500);
$black = imagecolorallocate($label, 0, 0, 0);
$white = imagecolorallocate($label, 255, 255, 255);
imagefill($label, 0, 0, $black);

imagettftext($label, 50, 0, 0, 150, $white, "arial.ttf", "UP UP UP");

$src = imagecreatefromjpeg("adidas.jpg");
$pic = imagecreatetruecolor(500, 500);
imagecopyresampled($label, $src, 0, 0, 0, 0, 150, 150, imagesx($src), imagesy($src));
$white2 = imagecolorallocate($pic, 255, 255, 255);

imagettftext($label, 50, 0, 0, 350, $white, "arial.ttf", "DOWN DOWN DOWN");

ob_end_clean();
header('Content-type: image/png');
imagepng($label);

imagedestroy($src);
imagedestroy($pic);
imagedestroy($label);
die();
?>