用php旋转png图像后如何获得透明背景? [英] How do i get a transparent background after rotaing a png image with php?

问题描述

所以我有png图像，但我旋转了它，但是我得到了黑色背景..或者如果我将颜色代码设为白色，我得到了白色..我尝试这样做..

So I have png image and I rotate it but i get a black background.. or if i do the color code ofr white i get white.. I tried doing this..

$trans = imagecolorallocatealpha(image, 0, 0, 0, 127);
imagerotate($image, $degree, $trans)

我也尝试过..

$trans = imagecolorallocatealpha($image, 255, 255, 255, 127);

有人可以帮我吗?

这是我的代码..如果我将allocatealpha更改为0、0、255、0，那么它将变为蓝色.但0、0、0、127仍为黑色.

here is my code.. if i change allocatealpha to 0, 0, 255, 0 then it goes blue. but with 0, 0, 0, 127 its still black.

function rotate($degrees) {
$image = $this->image;
imagealphablending($image, false);
$color = imagecolorallocatealpha($image, 0, 0, 0, 127);
imagefill($this->image, 0, 0, $color);
$rotate = imagerotate($image, $degrees, $color);
imagesavealpha($image, TRUE);
$this->image = $rotate;

function rotate($degrees) {
$image = $this->image;
imagealphablending($image, false);
$color = imagecolorallocatealpha($image, 0, 0, 0, 127);
imagefill($this->image, 0, 0, $color);
$rotate = imagerotate($image, $degrees, $color);
imagesavealpha($image, TRUE);
$this->image = $rotate;

推荐答案

$destimg = imagecreatefromjpeg("image.png");
$transColor = imagecolorallocatealpha($destimg, 255, 255, 255, 127);
$rotatedImage = imagerotate($destimg, 200, $transColor);
imagesavealpha($rotatedImage, true);
imagepng($rotatedImage,"rotated.png");

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