如何在php中绘制半透​​明矩形? [英] how to draw semi-transparent rectangle in php?

问题描述

这是我想做的一个例子:

Here is an example what I would like to do:

这是结果:

function red_rectangle($img_src,$x1,$y1,$x2,$y2,$tr = 50)
{
    // Load image
    $img = imagecreatefromjpeg($img_src);
    // Transparent red
    $red = imagecolorallocatealpha($img, 255, 0, 0, $tr);
    // Draw a white rectangle
    imagefilledrectangle($img, $x1, $y1, $x2, $y2, $red);
    // Save the image (overwrite)
    imagejpeg($img, $img_src);
    imagedestroy($img);
}

推荐答案

您需要使用 http://php.net/manual/zh-CN/function.imagefilledrectangle.php ，传递使用

You need to use http://php.net/manual/en/function.imagefilledrectangle.php, passing a color created with http://www.php.net/manual/en/function.imagecolorallocatealpha.php.

如您所见， http://php.net/manual/zh_cn/function.imagefilledrectangle.php 实际上是您要执行的操作.

As you can see, the example for http://php.net/manual/en/function.imagefilledrectangle.php is pratically what to you want to do.

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