使用CSS3或JS覆盖可见区域的透明黑色剪影PNG与模式

问题描述

我在寻找一种方式来覆盖一个透明的黑色剪影PNG文件与某种模式的可见区域。

是否有CSS，JavaScript混合解决方案？

示例：

演示：在Photoshop中，选择图层蒙版>叠加时，同样的结果是givin。 p>

Ps：我的问题类似于这个线程：剪切PNG图片。这使用canvas与globalCompositeOperation设置为destination-in。例如

  var canvas = document.createElement（'canvas'）; 
 canvas.width = 250; 
 canvas.height = 250; 
 
 var canvas_context = canvas.getContext（2d）; 
 
 var img = new Image（）; 
 img.onload = function（）{
 var msk = new Image（）; 
 msk.onload = function（）{
 canvas_context.drawImage（img，0，0）; 
 canvas_context.globalCompositeOperation =destination-in; 
 canvas_context.drawImage（msk，0，0）; 
 canvas_context.globalCompositeOperation =source-over; 
}; 
 
 msk.src ='silhouette.png'; 
} 
 img.src ='pattern.jpg'; 
 
 document.body.appendChild（canvas）; 
  

I'm looking for a way to overlay the visible areas of a transparent black silhouette PNG file with a certain pattern.

Is there a CSS, JavaScript, mixed solution for this?

Example: I have one image of a weapon silhoutte and a set of camo patterns which I want to lay over the weapon.

Demo: In Photoshop the same result is givin when selecting layer mask > overlay.

Ps: my question is similar to this thread: Silhouette a PNG image using CSS except I am looking for the exact opposite.

解决方案

You can do this using canvas with globalCompositeOperation set to destination-in. For example

var canvas = document.createElement('canvas');
canvas.width = 250;
canvas.height = 250;

var canvas_context = canvas.getContext("2d");

var img = new Image();
img.onload = function(){
    var msk = new Image();
    msk.onload = function(){
        canvas_context.drawImage(img, 0, 0);
        canvas_context.globalCompositeOperation = "destination-in";
        canvas_context.drawImage(msk, 0, 0);
        canvas_context.globalCompositeOperation = "source-over";
    };

    msk.src = 'silhouette.png';
}
img.src = 'pattern.jpg';

document.body.appendChild(canvas);

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