Why does a box appear when adding Chinese characters to a picture in PHP? How to solve it?

Solution to display the watermark of Chinese characters as boxes in PHP pictures

When adding Chinese characters to images in PHP, you often encounter the problem of Chinese characters being displayed as boxes. This article analyzes the causes of this problem and provides solutions.

Problem description: The user writes PHP code according to the online tutorial to add Chinese characters to the picture. The other parts of the code run normally, but the Chinese characters are displayed as boxes.

Some code examples:

 <?php header("content-type: text/html; charset=utf-8");
// ... (Code omitted) ...
$font = dirname(__file__) ."/simsunb.ttf"; //font file $content = "php Chinese website hhhhhhhh";
// ... (Code omitted) ...
imagettftext($image, 20, 0, 20, 30, $col, $font, $content);
// ... (Code omitted) ...
?>

Users have tried various character encoding conversion methods ( iconv , mb_convert_encoding ), but the problem still exists.

The root cause of the problem: After troubleshooting, the problem lies in the font file simsunb.ttf itself. This font may not contain all Chinese characters in its entirety, resulting in some Chinese characters not being rendered correctly and displayed as boxes.

Solution: Replace the font file. Use a font file that contains all the required Chinese characters to solve the problem.

After changing the font, the code runs normally and the Chinese character watermark displays correctly.

Summary: When adding Chinese characters watermarks using the imagettftext function in PHP, it is crucial to ensure that the font file used supports all required Chinese characters. Choosing the right font file is the key to solving the problem of Chinese characters displaying as boxes.

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