# imageopenpolygon

(PHP 7 >= 7.2.0)

imageopenpolygon — Draws an open polygon

### 说明

imageopenpolygon ( resource `$image` , array `$points` , int `$num_points` , int `$color` ) : bool

imageopenpolygon() draws an open polygon on the given `image`. Contrary to imagepolygon(), no line is drawn between the last and the first point.

### 参数

`image`

  由图象创建函数(例如imagecreatetruecolor())返回的图象资源。

`points`

  An array containing the polygon's vertices, e.g.:

  points[0] | = x0
  points[1] | = y0
  points[2] | = x1
  points[3] | = y1

`num_points`

  Total number of points (vertices).

`color`

  A color identifier created with imagecolorallocate().

### 返回值

成功时返回 `TRUE`， 或者在失败时返回 `FALSE`。

### 范例

Example #1 imageopenpolygon() example

    <?php
    // Create a blank image
    $image = imagecreatetruecolor(400, 300);

    // Allocate a color for the polygon
    $col_poly = imagecolorallocate($image, 255, 255, 255);

    // Draw the polygon
    imageopenpolygon($image, array(
            0,   0,
            100, 200,
            300, 200
        ),
        3,
        $col_poly);

    // Output the picture to the browser
    header('Content-type: image/png');

    imagepng($image);
    imagedestroy($image);
    ?>

以上例程的输出类似于：

### 参见

- imagepolygon() - 画一个多边形