Question

我在2d字段上有几个对象： https://i.imgsafe.org/4d9f0a2.png

我需要在程序化分组时计算项目的大小： https://i.imgsafe.org/7697e03.png

我有每个物体的弧度大小，位置和旋转。

有人知道这种做法或做法吗？

我需要在PHP中完成。

使用一些代码进行更新：

class Layer {
    /**
     * @var float The X position
     */
    public $x;
    /**
     * @var float The Y position
     */
    public $y;
    /**
     * @var float The width of the rectanlge 
     */
    public $width;
    /**
     *
     * @var float The height of the rectangle
     */
    public $height;
    /**
     *
     * @var float The rotation in radians
     */
    public $rotation;
}

$layers = array();

$layers[0] = new Layer();
$layers[0]->x = 10;
$layers[0]->y = 10;
$layers[0]->width = 100;
$layers[0]->height = 200;
$layers[0]->rotation = 0.3;

$layers[1] = new Layer();
$layers[1]->x = 50;
$layers[1]->y = 60;
$layers[1]->width = 200;
$layers[1]->height = 300;
$layers[1]->rotation = 1;

$layers[2] = new Layer();
$layers[2]->x = 100;
$layers[2]->y = 300;
$layers[2]->width = 200;
$layers[2]->height = 150;
$layers[2]->rotation = 0.3;

我现在需要一种循环遍历$ layers来计算边界框的方法。

Answer 1

我认为这是正确的计算：

    $layers = array();

    $layers[0] = new Layer();
    $layers[0]->x = 10;
    $layers[0]->y = 10;
    $layers[0]->width = 100;
    $layers[0]->height = 200;
    $layers[0]->rotation = 0.3;

    $layers[1] = new Layer();
    $layers[1]->x = 50;
    $layers[1]->y = 60;
    $layers[1]->width = 200;
    $layers[1]->height = 300;
    $layers[1]->rotation = 0.1;

    $layers[2] = new Layer();
    $layers[2]->x = 100;
    $layers[2]->y = 300;
    $layers[2]->width = 200;
    $layers[2]->height = 150;
    $layers[2]->rotation = 0.3;

    print_r($layers);

    $boundingBoxes = array();
    foreach($layers as $layerKey => $layer) {
      $intWidthRotated = $layer->height * abs( sin( $layer->rotation) ) + $layer->width * abs( cos( $layer->rotation ) );
      $intHeightRotated = $layer->height * abs( cos( $layer->rotation ) ) + $layer->width * abs( sin( $layer->rotation ) );
      $boundingBoxes[$layerKey] = array( $intWidthRotated, $intHeightRotated );
    }
    print_r($boundingBoxes);

    $boundingBox = array();
    $minX = null;
    $maxX = null;
    $minY = null;
    $maxY = null;
    foreach($layers as $layerKey => $layer) {
            $minX = $minX == null ? $layer->x : $minX >= $layer->x ? $layer->x : $minX;
            $maxX = $maxX == null ? $layer->x + $boundingBoxes[$layerKey][0] : $maxX <= $layer->x + $boundingBoxes[$layerKey][0] ? $layer->x + $boundingBoxes[$layerKey][0] : $maxX;

            $minY = $minY == null ? $layer->y : $minY >= $layer->y ? $layer->y : $minY;
            $maxY = $maxY == null ? $layer->y + $boundingBoxes[$layerKey][1] : $maxY <= $layer->y + $boundingBoxes[$layerKey][1] ? $layer->y + $boundingBoxes[$layerKey][1] : $maxY;
    }

    $boundingBox = array(
            'x' => $minX,
            'y' => $minY,
            'width' => $maxX,
            'height' => $maxY
    );

    print_r($boundingBox);

PHP计算几个2D对象的边界框

1 个答案: