What to do if php imagestring Chinese garbled characters

php imagestring Chinese garbled characters are caused by the fact that the GD2 library itself does not have Chinese fonts. The solution is to specify a font to display the output string.

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imagestring function displays Chinese garbled characters

1. Problem description

When I learned to watermark images, I used PHP’s built-in GD extension function library and the imagestring used in the video tutorial ( resource $image , int $font , int $x , int $y, string $s, int $col) function. In practical applications, it was found that this function cannot display Chinese watermarks normally and displays Chinese garbled characters.

2. Solution process

By querying the official website PHP manual, imagestring: draw a line of string horizontally, imagestring() uses col color to draw the string s to the x of the image represented by image , at the y coordinate (this is the coordinate of the upper left corner of the string, and the upper left corner of the entire image is 0, 0). If font is 1, 2, 3, 4 or 5, the built-in font is used.

The second parameter $font of this function is the font parameter, but the official only states that if the value is set to 1-5, the built-in font will be used. However, through testing, it was found that the so-called built-in fonts 1-5 are not normal. Display Chinese. Moreover, the official document does not explain whether other values ​​​​and other font files other than 1-5 can be used. The test found that when this parameter is set to other font files, it cannot be used normally.

After searching for relevant content online, I found that in most cases, the failure to display Chinese is caused by the fact that the GD2 library itself does not have Chinese fonts, so a font must be specified to display the output string. If you want to output Chinese on the picture, you should use the imagettftext (resource $image, float $size, float $angle, int $x, int $y, int $color, string $fontfile, string $text) function. The official description of this function is: Use TrueType font to write text to the image

The second parameter of this function is also a font file, which should point to a font file in ttf format. Through testing, it was found that Chinese can be displayed normally. $font is the path of the font file. When the font file is placed in the same directory as the php file, it is the name of the font file.

In addition, I found in the PHP manual that there is another imagefttext (resource$image, float$size, float$angle, int$x, int$y, int$color, string$fontfile, string$text [, array$extrainfo ] )t function,

The official description of this function is: Use FreeType 2 font to write text into the image, very similar to the imagettftext function above. Only the referenced font file types are different, so maybe you can also display Chinese using this function. But I'm too lazy to try it. . . If you are interested, you can try it.

I accidentally discovered that under the Ubuntu system, the font file used is placed in the directory of the same level as the php. When $font is the name of the file, I find that the function cannot take effect normally. I found imagettftext() by querying the error log. : Could not find/open font, I learned through Baidu query that in the Linux system, it is not possible to just set $font as the file name. You must also specify the path, such as './xxx.ttf' (relative path) or ' /usr/share/fonts/xxx.ttf' (absolute path). The test found that it can be displayed normally.

3. Summary:

Imagestring can hardly display Chinese normally. Maybe there are other methods. However, it is recommended to use imagettftext, which is simple and convenient. You only need to import a font file.

The $font parameter of the imagettftext function only needs to be set to the file name in the window system and the font file will be searched for in the current directory. However, in the Linux system, the path must be specified, which is ./.

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