php GD创建一个透明的png图像

I'm trying to create a transparent png image and layer various other pngs and jpgs to create a final png with transparency. I'm having trouble creating my initial empty transparent png. It currently has a white background.

我正在尝试创建一个透明的png图像，并将各种其他png和jpgs分层，以创建一个具有透明度的最终png。我在创建我的初始空透明png时遇到了麻烦。它目前有白色背景。

Can anyone point me in the right direction. This is my code so far...

任何人都可以指出我正确的方向。到目前为止这是我的代码......

$image = imagecreatetruecolor(485, 500);
imagealphablending($image, false);
imagesavealpha($image, true);
$col=imagecolorallocatealpha($image,255,255,255,127);
imagefill($image, 0, 0, $col);
//imagefilledrectangle($image,0,0,485, 500,$col);


/* add door glass */
$img_doorGlass = imagecreatefrompng("glass/$doorStyle/$doorGlass.png");     
imagecopyresampled($image, $img_doorGlass, 106, 15, 0, 0, 185, 450, 185, 450);              


/* add door */
$img_doorStyle = imagecreatefrompng("door/$doorStyle/$doorStyle"."_"."$doorColor.png");     
imagecopyresampled($image, $img_doorStyle, 106, 15, 0, 0, 185, 450, 185, 450);


$fn = md5(microtime()."door_builder").".png";

if(imagepng($image, "user_doors/$fn", 1)){
  echo "user_doors/$fn";
}       
imagedestroy($image);

3 个解决方案

#1

Set imagealphablending($image,true); on each new layer.

设置imagealphablending（$ image，true）;在每个新图层上。

Try this:

尝试这个：

<?php
$image = imagecreatetruecolor(485, 500);
imagealphablending($image, false);
$col=imagecolorallocatealpha($image,255,255,255,127);
imagefilledrectangle($image,0,0,485, 500,$col);
imagealphablending($image,true);

/* add door glass */
$img_doorGlass = imagecreatefrompng("glass/$doorStyle/$doorGlass.png");
imagecopyresampled($image, $img_doorGlass, 106, 15, 0, 0, 185, 450, 185, 450);
imagealphablending($image,true);

/* add door */
$img_doorStyle = imagecreatefrompng("door/$doorStyle/$doorStyle"."_"."$doorColor.png");
imagecopyresampled($image, $img_doorStyle, 106, 15, 0, 0, 185, 450, 185, 450);
imagealphablending($image,true);

$fn = md5(microtime()."door_builder").".png";

imagealphablending($image,false);
imagesavealpha($image,true);
if(imagepng($image, "user_doors/$fn", 1)){
    echo "user_doors/$fn";
}
imagedestroy($image);

?>

#2

This code worked for me:

这段代码对我有用：

$img=imagecreatetruecolor(180,20);
imagealphablending($img,false);

$col=imagecolorallocatealpha($img,255,255,255,127);
imagefilledrectangle($img,0,0,180,20,$col);
imagealphablending($img,true);

$font=$_SERVER["DOCUMENT_ROOT"].'/fonts/Arial.ttf';
$color = imagecolorallocate($img, 140, 173, 209);
imagettftext($img,11,0,5,14,$color,$font,'Text goes here'); 

header('Content-Type: image/png');
imagealphablending($img,false);
imagesavealpha($img,true);
imagepng($img);

#3

Try to replace
$col=imagecolorallocatealpha($image,255,255,255,127);
with
$col=imagecolorallocate($image,255,255,255);

尝试替换$ col = imagecolorallocatealpha（$ image，255,255,255,127）; with $ col = imagecolorallocate（$ image，255,255,255）;

and try to uncomment imagefilledrectangle line.
I can test this code - give me the pictures :)

并尝试取消注释imagefilledrectangle行。我可以测试这段代码 - 给我照片:)

#1