imagettftext
(PHP 4, PHP 5)
imagettftext — 用 TrueType 字体向图像写入文本
说明
$image
, float $size
, float $angle
, int $x
, int $y
, int $color
, string $fontfile
, string $text
)
-
image - 图像资源。见 imagecreatetruecolor()。
-
size - 字体大小。根据 GD 版本不同，应该以像素大小指定（GD1）或点大小（GD2）。
-
angle - 角度制表示的角度，0 度为从左向右读的文本。更高数值表示逆时针旋转。例如 90 度表示从下向上读的文本。
-
x -
由
x，y所表示的坐标定义了第一个字符的基本点（大概是字符的左下角）。这和 imagestring() 不同，其 x，y 定义了第一个字符的左上角。例如 "top left" 为 0, 0。 -
y - Y 坐标。它设定了字体基线的位置，不是字符的最底端。
-
color - 颜色索引。使用负的颜色索引值具有关闭防锯齿的效果。见 imagecolorallocate()。
-
fontfile -
是想要使用的 TrueType 字体的路径。
根据 PHP 所使用的 GD 库的不同，当
fontfile没有以 / 开头时则 .ttf 将被加到文件名之后并且会在库定义字体路径中尝试搜索该文件名。 当使用的 GD 库版本低于 2.0.18 时，一个空格字符 而不是分号将被用来作为不同字体文件的“路径分隔符”。不小心使用了此特性将会导致一条警告信息：Warning: Could not find/open font。对受影响的版本来说唯一解决方案就是将字体移动到不包含空格的路径中去。很多情况下字体都放在脚本的同一个目录下。下面的小技巧可以减轻包含的问题。
<?php
// Set the enviroment variable for GD
putenv('GDFONTPATH=' . realpath('.'));
// Name the font to be used (note the lack of the .ttf extension)
$font = 'SomeFont';
?> -
text - 文本字符串。 可以包含十进制数字化字符表示（形式为：€）来访问字体中超过位置 127 的字符。UTF-8 编码的字符串可以直接传递。 如果字符串中使用的某个字符不被字体支持，一个空心矩形将替换该字符。
imagettftext() 返回一个含有 8 个单元的数组表示了文本外框的四个角，顺序为坐下角，右下角，右上角，左上角。这些点是相对于文本的而和角度无关，因此“左上角”指的是以水平方向看文字时其左上角。
Example #1 imagettftext() 例子
本例中的脚本将生成一个白色的 400x30 像素 PNG 图像，其中有黑色（带灰色阴影）Arial 字体写的“Testing...”。
<?php
// Set the content-type
header("Content-type: image/png");
// Create the image
$im = imagecreatetruecolor(400, 30);
// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 29, $white);
// The text to draw
$text = 'Testing...';
// Replace path by your own font path
$font = 'arial.ttf';
// Add some shadow to the text
imagettftext($im, 20, 0, 11, 21, $grey, $font, $text);
// Add the text
imagettftext($im, 20, 0, 10, 20, $black, $font, $text);
// Using imagepng() results in clearer text compared with imagejpeg()
imagepng($im);
imagedestroy($im);
?>
本函数同时需要 GD 库和 » FreeType 库。
参见 imagettfbbox()。
参数
-
image -
由图象创建函数(例如 imagecreatetruecolor())返回的图象资源。
-
size -
字体的尺寸. 根据GD的版本,为像素尺寸(GD1)或点(磅)尺寸 (GD2).
-
angle -
The angle in degrees, with 0 degrees being left-to-right reading text. Higher values represent a counter-clockwise rotation. For example, a value of 90 would result in bottom-to-top reading text.
-
x -
The coordinates given by
xandywill define the basepoint of the first character (roughly the lower-left corner of the character). This is different from the imagestring(), wherexandydefine the upper-left corner of the first character. For example, "top left" is 0, 0. -
y -
The y-ordinate. This sets the position of the fonts baseline, not the very bottom of the character.
-
color -
The color index. Using the negative of a color index has the effect of turning off antialiasing. See imagecolorallocate().
-
fontfile -
The path to the TrueType font you wish to use.
Depending on which version of the GD library PHP is using, when
fontfiledoes not begin with a leading / then .ttf will be appended to the filename and the library will attempt to search for that filename along a library-defined font path.When using versions of the GD library lower than 2.0.18, a space character, rather than a semicolon, was used as the 'path separator' for different font files. Unintentional use of this feature will result in the warning message: Warning: Could not find/open font. For these affected versions, the only solution is moving the font to a path which does not contain spaces.
In many cases where a font resides in the same directory as the script using it the following trick will alleviate any include problems.
<?php
// Set the enviroment variable for GD
putenv('GDFONTPATH=' . realpath('.'));
// Name the font to be used (note the lack of the .ttf extension)
$font = 'SomeFont';
?> -
text -
The text string in UTF-8 encoding.
May include decimal numeric character references (of the form: €) to access characters in a font beyond position 127. The hexadecimal format (like ©) is supported. Strings in UTF-8 encoding can be passed directly.
Named entities, such as ©, are not supported. Consider using html_entity_decode() to decode these named entities into UTF-8 strings (html_entity_decode() supports this as of PHP 5.0.0).
If a character is used in the string which is not supported by the font, a hollow rectangle will replace the character.
返回值
Returns an array with 8 elements representing four points making the
bounding box of the text. The order of the points is lower left, lower
right, upper right, upper left. The points are relative to the text
regardless of the angle, so "upper left" means in the top left-hand
corner when you see the text horizontally.
Returns FALSE on error.
更新日志
| 版本 | 说明 |
|---|---|
| 5.2.0 |
It is now possible to specify an hexadecimal entity in
text.
|
范例
Example #2 imagettftext() example
This example script will produce a white PNG 400x30 pixels, with the words "Testing..." in black (with grey shadow), in the font Arial.
<?php
// Set the content-type
header('Content-Type: image/png');
// Create the image
$im = imagecreatetruecolor(400, 30);
// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 399, 29, $white);
// The text to draw
$text = 'Testing...';
// Replace path by your own font path
$font = 'arial.ttf';
// Add some shadow to the text
imagettftext($im, 20, 0, 11, 21, $grey, $font, $text);
// Add the text
imagettftext($im, 20, 0, 10, 20, $black, $font, $text);
// Using imagepng() results in clearer text compared with imagejpeg()
imagepng($im);
imagedestroy($im);
?>
以上例程的输出类似于：
注释
Note:
This function requires both the GD library and the » FreeType library.