php watermark text garbled

In the process of website development, adding watermarks to images is a common requirement. When using PHP to add watermark text, sometimes you will encounter the problem of garbled watermark text. Let's discuss the solution to this problem.

1. Character encoding issues

In PHP, strings can be encoded in many ways, among which the common ones are Unicode, ASCII, GBK, UTF-8, etc. When adding watermark text, if the encoding method used is incorrect, the watermark text will be garbled.

Generally, we use UTF-8 encoding most commonly because it supports multiple languages, including English, Chinese, Japanese, etc. Therefore, when adding watermark text, we can set the encoding method of the string to UTF-8 to avoid garbled characters.

You can use the following code to set the encoding method to UTF-8:

header('Content-Type: text/html;charset=utf-8');

2. Font file problem

The watermark text garbled problem may also be related to the font file. When using PHP to add watermark text, we need to specify the path and font size of the font file. If the specified font file does not exist or does not support the character set we need, the watermark text will be garbled.

In order to avoid this situation, we should choose a font file suitable for the character set we use and place the font file in an accessible directory. At the same time, we also need to pay attention to the font size setting to prevent the watermark text from being too small or too large, which affects the appearance.

3. Function usage issues

In PHP, there are a variety of functions that can be used to add watermark text, such as imagestring(), imagettftext(), etc. Different functions require different parameters, and improper use may cause garbled text in the watermark.

If this happens, we should check whether the function used is suitable for our needs and confirm whether the parameters are set correctly. When using imagettftext() to add watermark text, we also need to pay attention to specifying the correct font file path, font size, text color and other information.

The following is an example:

<?php header("Content-type:image/png");
$img = imagecreatefrompng("test.png");
$font = 'msyh.ttc';
$size = 20;
$angle = 0;
$text = "测试文字";
$color = imagecolorallocate($img, 255, 0, 0);
imagettftext($img, $size, $angle, 10, 50, $color, $font, $text);
imagepng($img);
imagedestroy($img);
?>

When using the above code to add watermark text, we need to confirm whether the font file msyh.ttc exists and ensure that it supports the added text, otherwise it will Garbled characters appear.

4. Solution

To sum up, if you encounter the problem of garbled watermark text added by PHP, we need to check the following aspects:

(1) characters Whether the encoding method of the string is UTF-8;

(2) Select a font file suitable for the character set we use and place it in an accessible directory;

(3) Confirm that the function used is suitable for our needs and check that the parameters are set correctly.

If there are no problems in the above aspects, but the watermark text is still garbled, then you need to use the PHP extension library to solve this problem.

Common solutions include using extension libraries such as mbstring and iconv to convert character encodings. Here we take the mbstring extension library as an example to introduce how to use it to solve the problem of garbled watermark text:

(1) Install the mbstring extension library:

yum install php-mbstring

(2) In the code Add the following code:

mb_internal_encoding("UTF-8");
$text = "测试文字";
$text = mb_convert_encoding($text, "HTML-ENTITIES", "UTF-8");
imagettftext($im, 14, 0, 10, 20, $text_color, $font, $text);

In this way, after using the mbstring extension library, you can correctly add watermark text to the image.

Summary

The above is the solution to the garbled PHP watermark text. Determine the cause of the problem and confirm whether the encoding method, font file and function usage are correct. If it cannot be solved, use the PHP extension library to handle it, so that you can correctly add watermark text to the image.

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