position有9个点：lt,mt,rt,lm,mm,rm,lb,mb,rb，其实对应的是几个英文：lt(left top),mt(middle top),rt(right top)，以此类推
上官方原图：
OK，然后我们看一下他的代码是怎么写的，如果有人涉及到也可以借鉴：
PHP代码
- <?php
- /**
- * Calculate the left top positions of a layer inside a parent layer container
- * $position: http://phpimageworkshop.com/doc/22/corners-positions-schema-of-an-image.html
- *
- * @param integer $containerWidth
- * @param integer $containerHeight
- * @param integer $layerWidth
- * @param integer $layerHeight
- * @param integer $layerPositionX
- * @param integer $layerPositionY
- * @param string $position
- *
- * @return array
- */
- public static function calculatePositions($containerWidth, $containerHeight, $layerWidth, $layerHeight, $layerPositionX, $layerPositionY, $position = 'LT')
- {
- $position = strtolower($position);
- if ($position == 'rt') {
- $layerPositionX = $containerWidth - $layerWidth - $layerPositionX;
- } elseif ($position == 'lb') {
- $layerPositionY = $containerHeight - $layerHeight - $layerPositionY;
- } elseif ($position == 'rb') {
- $layerPositionX = $containerWidth - $layerWidth - $layerPositionX;
- $layerPositionY = $containerHeight - $layerHeight - $layerPositionY;
- } elseif ($position == 'mm') {
- $layerPositionX = (($containerWidth - $layerWidth) / 2) + $layerPositionX;
- $layerPositionY = (($containerHeight - $layerHeight) / 2) + $layerPositionY;
- } elseif ($position == 'mt') {
- $layerPositionX = (($containerWidth - $layerWidth) / 2) + $layerPositionX;
- } elseif ($position == 'mb') {
- $layerPositionX = (($containerWidth - $layerWidth) / 2) + $layerPositionX;
- $layerPositionY = $containerHeight - $layerHeight - $layerPositionY;
- } elseif ($position == 'lm') {
- $layerPositionY = (($containerHeight - $layerHeight) / 2) + $layerPositionY;
- } elseif ($position == 'rm') {
- $layerPositionX = $containerWidth - $layerWidth - $layerPositionX;
- $layerPositionY = (($containerHeight - $layerHeight) / 2) + $layerPositionY;
- }
- return array(
- 'x' => $layerPositionX,
- 'y' => $layerPositionY,
- );
- }
END;
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