ImagickDraw::setGravity()

(PECL imagick 2.0.0)

Sets the text placement gravity

说明

ImagickDraw::setGravity(int $gravity): bool

Warning

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.

参数

$gravity

GRAVITY_ constant

返回值

没有返回值。

范例

Example #1 ImagickDraw::setGravity()

<?php
function setGravity($fillColor, $strokeColor, $backgroundColor) {
    $draw = new \ImagickDraw();
    $draw->setStrokeColor($strokeColor);
    $draw->setFillColor($fillColor);
    $draw->setStrokeWidth(1);
    $draw->setFontSize(24);
    $gravitySettings = array(
        \Imagick::GRAVITY_NORTHWEST => 'NorthWest',
        \Imagick::GRAVITY_NORTH => 'North',
        \Imagick::GRAVITY_NORTHEAST => 'NorthEast',
        \Imagick::GRAVITY_WEST => 'West',
        \Imagick::GRAVITY_CENTER => 'Centre',
        \Imagick::GRAVITY_SOUTHWEST => 'SouthWest',
        \Imagick::GRAVITY_SOUTH => 'South',
        \Imagick::GRAVITY_SOUTHEAST => 'SouthEast',
        \Imagick::GRAVITY_EAST => 'East'
    );
    $draw->setFont("../fonts/Arial.ttf");
    foreach ($gravitySettings as $type => $description) {
        $draw->setGravity($type);
        $draw->annotation(50, 50, '"' . $description . '"');
    }
    $imagick = new \Imagick();
    $imagick->newImage(500, 500, $backgroundColor);
    $imagick->setImageFormat("png");
    $imagick->drawImage($draw);
    header("Content-Type: image/png");
    echo $imagick->getImageBlob();
}
?>

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

It appears that the GRAVITY constants have an integer equivalent:
NORTHWEST = 1
NORTH = 2
NORTHEAST = 3
WEST = 4 
CENTER = 5
EAST = 6
SOUTHWEST = 7
SOUTH = 8
SOUTHEAST = 9