使用PHP将2-3个透明的PNG图像相互叠加

Question

我正在为一个项目开发一个自定义的头像系统,但我从来没有真正做过PHP的图像方面.我想我需要以某种方式使用GD,但我不知道从哪里开始.

基本上,有一堆预先制作的透明PNG图像.用户可以选择其中的2-3个来自定义他们的头像,我希望能够拍摄这些图像并从中制作单个图像以存储在文件夹中.

Answer 1

$image_1 = imagecreatefrompng('image_1.png');
$image_2 = imagecreatefrompng('image_2.png');
imagealphablending($image_1, true);
imagesavealpha($image_1, true);
imagecopy($image_1, $image_2, 0, 0, 0, 0, 100, 100);
imagepng($image_1, 'image_3.png');

Answer 2

这有助于我从其他3个PNG文件创建PNG图像,以创建带背景的水印图像.希望它可以帮助别人.

$bgFile = __DIR__ . "/background-layer-1.png"; // 93 x 93

$imageFile = __DIR__ . "/icon-layer-2.png"; // 76 x 76

$watermarkFile = __DIR__ . "/stars-layer-3.png"; // 133 x 133 (是白星)

<?php
// Download the image files if we don't have them
function get_file($file, $from) {
    if (!file_exists(__DIR__ . "/" . $file)) { file_put_contents(__DIR__ . "/" . $file, file_get_contents($from)); }
}
get_file("background-layer-1.png", "http://i.imgur.com/6pgf3WK.png");
get_file("icon-layer-2.png", "http://i.imgur.com/0sJt52z.png");
get_file("stars-layer-3.png", "http://i.imgur.com/1Tvlokk.png");

$bgFile = __DIR__ . "/background-layer-1.png"; // 93 x 93
$imageFile = __DIR__ . "/icon-layer-2.png"; // 76 x 76
$watermarkFile = __DIR__ . "/stars-layer-3.png"; // 133 x 133

// We want our final image to be 76x76 size
$x = $y = 76;

// dimensions of the final image
$final_img = imagecreatetruecolor($x, $y);

// Create our image resources from the files
$image_1 = imagecreatefrompng($bgFile);
$image_2 = imagecreatefrompng($imageFile);
$image_3 = imagecreatefrompng($watermarkFile);

// Enable blend mode and save full alpha channel
imagealphablending($final_img, true);
imagesavealpha($final_img, true);

// Copy our image onto our $final_img
imagecopy($final_img, $image_1, 0, 0, 0, 0, $x, $y);
imagecopy($final_img, $image_2, 0, 0, 0, 0, $x, $y);
imagecopy($final_img, $image_3, 0, 0, 0, 0, $x, $y);

ob_start();
imagepng($final_img);
$watermarkedImg = ob_get_contents(); // Capture the output
ob_end_clean(); // Clear the output buffer

header('Content-Type: image/png');
echo $watermarkedImg; // outputs: `http://i.imgur.com/f7UWKA8.png`

输出:

Answer 3

也可以按照这样的方式进行。希望这对未来的访客有用。

$base = imagecreatefrompng('your base image path');
//logo is transparent: in this case stackoverflow logo
$logo = imagecreatefrompng("path for image with transparent background");

//Adjust paramerters according to your image
imagecopymerge_alpha($base, $logo, 60, 60, 0, 0, 300, 200, 100);

header('Content-Type: image/png');
imagepng($base);

//@see: http://php.net/manual/en/function.imagecopymerge.php for below function in first comment
function imagecopymerge_alpha($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h, $pct){ 
        // creating a cut resource 
        $cut = imagecreatetruecolor($src_w, $src_h); 

        // copying relevant section from background to the cut resource 
        imagecopy($cut, $dst_im, 0, 0, $dst_x, $dst_y, $src_w, $src_h); 

        // copying relevant section from watermark to the cut resource 
        imagecopy($cut, $src_im, 0, 0, $src_x, $src_y, $src_w, $src_h); 

        // insert cut resource to destination image 
        imagecopymerge($dst_im, $cut, $dst_x, $dst_y, 0, 0, $src_w, $src_h, $pct); 
    } 

工作示例：这是背景图片
这是 stackoverflow 徽标。

这是合并结果。