(PECL imagick 2.0.0)
ImagickDraw::setGravity — Sets the text placement gravity
$gravity
)本函数还未编写文档，仅有参数列表。
Sets the text placement gravity to use when annotating with text.
gravity
GRAVITY_ constant
没有返回值。
alan at ridersite dot org (2007-08-28 07:51:21)
Gravity constants are very useful as they can save having to calculate the placement of variable text strings and font sizes.
For example:
$draw->setGravity (Imagick::GRAVITY_CENTER);
$image->annotateImage($draw, 0, 0, 0, 'The quick brown fox jumps over the lazy dog');
Will horizontally and vertically center the text string.
Note, there are several gravity constants available. See, Constants — Imagick class constants