无法使用下面的文本创建 QR

Question

我使用此代码制作带有下方自定义文本的二维码。我尝试了几种方法，但总是失败。我需要帮忙。

// Set the content-type
header('Content-Type: image/png');
header("Content-Disposition: filename='sample.png'");
$main = imagecreatetruecolor(150, 180);
$qr = imagecreatefrompng("https://api.qrserver.com/v1/create-qr-code/?size=150x150&format=png&margin=5&data=sample");
// Create the image
$im = imagecreatetruecolor(150, 30);
// Create some colors
$black = imagecolorallocate($im, 255, 255, 255);
imagefilledrectangle($im, 0, 0, 399, 29, $black);
// Font path
$font = 'arial.ttf';
// Add the text
imagettftext($im, 20, 0, 5, 25, $black, $font, 'sample');
imagecopymerge_alpha($main, $qr, 0, 0, 0, 0, 150, 150, 100);
imagecopymerge_alpha($main, $im, 0, 150, 0, 0, 150, 30, 100);
imagepng($main);
imagedestroy($main);

我只看到空白页。

Answer 1

你有一个错误，但你不能在浏览器中查看它，因为你已经设置了 Content-Type: image/png 所以为了调试，只需注释掉该行或检查你的服务器日志。

我首先想到的是this answer using a relative path to your font. This is enough to throw a warning that if output to screen would garble your image, and not to mention you won't have the font you needed. I would fix this line。

$font = realpath(__DIR__.'/arial.ttf');

对我来说，致命错误是：

Call to undefined function imagecopymerge_alpha()

我不确定你从哪里得到该代码，但我找到了，所以我认为它可能是相关的。

function imagecopymerge_alpha($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct){
    // creating a cut resource
    $cut = imagecreatetruecolor($src_w, $src_h);

    // copying relevant section from background to the cut resource
    imagecopy($cut, $dst_im, 0, 0, $dst_x, $dst_y, $src_w, $src_h);

    // copying relevant section from watermark to the cut resource
    imagecopy($cut, $src_im, 0, 0, $src_x, $src_y, $src_w, $src_h);

    // insert cut resource to destination image
    imagecopymerge($dst_im, $cut, $dst_x, $dst_y, 0, 0, $src_w, $src_h, $pct);
}

然后我注意到白色被标记为黑色并设置为背景和文本颜色 - 所以无论它是哪种颜色，它都不会可见。所以我changed these lines。（- 表示删除行，+ 表示添加行。）

 // Create the image
 $im = imagecreatetruecolor(150, 30);
 // Create some colors
-$black = imagecolorallocate($im, 255, 255, 255);
+$white = imagecolorallocate($im, 255, 255, 255);
+$black = imagecolorallocate($im, 0, 0, 0);
 imagefilledrectangle($im, 0, 0, 399, 29, $black);
 // Font path
 $font = realpath(__DIR__.'/arial.ttf');
 // Add the text
-imagettftext($im, 20, 0, 5, 25, $black, $font, 'sample');
+imagettftext($im, 20, 0, 5, 25, $white, $font, 'sample');
 imagecopymerge_alpha($main, $qr, 0, 0, 0, 0, 150, 150, 100);
 imagecopymerge_alpha($main, $im, 0, 150, 0, 0, 150, 30, 100);
 imagepng($main);

最后，为了好玩，我将其设置为查询字符串，而不是对单词 sample 进行硬编码。

+$text = $_GET['qr'] ?? 'sample';
+
 // Set the content-type
 header('Content-Type: image/png');
 header("Content-Disposition: filename='sample.png'");
 $main = imagecreatetruecolor(150, 180);
-$qr = imagecreatefrompng("https://api.qrserver.com/v1/create-qr-code/?size=150x150&format=png&margin=5&data=sample");
+$qr = imagecreatefrompng("https://api.qrserver.com/v1/create-qr-code/?size=150x150&format=png&margin=5&data=$text");
 // Create the image
 $im = imagecreatetruecolor(150, 30);
 // Create some colors
@@ -14,7 +16,7 @@ imagefilledrectangle($im, 0, 0, 399, 29, $black);
 // Font path
 $font = realpath(__DIR__.'/arial.ttf');
 // Add the text
-imagettftext($im, 20, 0, 5, 25, $white, $font, 'sample');
+imagettftext($im, 20, 0, 5, 25, $white, $font, $text);

GET /

GET /?qr=hello

<?php

$text = $_GET['qr'] ?? 'sample';

// Set the content-type
header('Content-Type: image/png');
header("Content-Disposition: filename='sample.png'");
$main = imagecreatetruecolor(150, 180);
$qr = imagecreatefrompng("https://api.qrserver.com/v1/create-qr-code/?size=150x150&format=png&margin=5&data=$text");
// Create the image
$im = imagecreatetruecolor(150, 30);
// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 29, $black);
// Font path
$font = realpath(__DIR__.'/arial.ttf');
// Add the text
imagettftext($im, 20, 0, 5, 25, $white, $font, $text);
imagecopymerge_alpha($main, $qr, 0, 0, 0, 0, 150, 150, 100);
imagecopymerge_alpha($main, $im, 0, 150, 0, 0, 150, 30, 100);
imagepng($main);
imagedestroy($main);

function imagecopymerge_alpha($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct){
    // creating a cut resource
    $cut = imagecreatetruecolor($src_w, $src_h);

    // copying relevant section from background to the cut resource
    imagecopy($cut, $dst_im, 0, 0, $dst_x, $dst_y, $src_w, $src_h);

    // copying relevant section from watermark to the cut resource
    imagecopy($cut, $src_im, 0, 0, $src_x, $src_y, $src_w, $src_h);

    // insert cut resource to destination image
    imagecopymerge($dst_im, $cut, $dst_x, $dst_y, 0, 0, $src_w, $src_h, $pct);
}

无法使用下面的文本创建 QR

Can't Create QR With Text Below

php

api

imagecreatefrompng