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我有一张这样的图片像这样的图像,我想用这样的图案填充这样像这样的结果像这样

我可以使用以下代码填充图案,但我不知道如何沿着衣领形状正确弯曲图案,因为它应该看起来像真实的,但我的结果变成了这样。像这样.

这是我的示例脚本

$(function(){
drawCanvas("body","collar","images/collar.png", 180);

function drawCanvas(overlayType, canvasID, imageSource, degreeRotate){
    var canvas=document.getElementById(canvasID);
    var ctx=canvas.getContext("2d");

    var imgBody=new Image();
    var imgPattern=new Image();
    imgPattern.onload=function(){

        imgBody.onload=function(){
            start();
        }

        imgBody.src=imageSource;
    }
    imgPattern.src="images/pattern.png";

    function start(){
        ctx.drawImage(imgBody,0,0);
        if(overlayType=="body"){
            ctx.globalCompositeOperation="source-atop";
            ctx.globalAlpha=.85;

            var pattern = ctx.createPattern(imgPattern, 'repeat');
            ctx.fillStyle = pattern;
            ctx.rect(0, 0, canvas.width, canvas.height);
            ctx.rotate(degreeRotate * Math.PI/180);

            ctx.fill();
            ctx.translate(150,0);

            ctx.globalAlpha=.1;     
            ctx.drawImage(imgBody,150,0);   
        }
    }
}});

有人可以指导我如何管理图案以沿着侧领形状弯曲以看起来像真的吗?

4

2 回答 2

1

您可以通过简单地垂直切割和偏移您的图案来实现这一点

原“领”图:

在此处输入图像描述

充满弯曲方格纹理的衣领

在此处输入图像描述

**方法:*

  • 创建与您的方格纹理平铺的图像。
  • 将该纹理图像绘制到临时画布上。
  • 获取临时画布的图像数据。
  • 对于每一列像素,将整列偏移你领子的曲线。
  • 二次曲线非常适合您的衣领曲线,所以我在示例中使用它来确定 Y 偏移量。
  • 将图像数据放回临时画布上。
  • (您现在有一个弯曲的方格图案可应用于您的衣领图像)。
  • 在主画布上绘制衣领图像。
  • 设置 context.globalCompositeOperation=”source-atop”</li>
  • 将临时画布中的纹理绘制到主画布上。
  • (合成模式只会在衣领上绘制纹理,而不是背景)

这是代码和小提琴:http: //jsfiddle.net/m1erickson/hdXyk/

<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>

<style>
    body{ background-color: ivory; padding:20px; }
    canvas{border:1px solid red;}
</style>

<script>
$(function(){

    // get canvas references (canvas=collar, canvas1=texture)
    var canvas=document.getElementById("canvas");
    var ctx=canvas.getContext("2d");
    var canvas1=document.getElementById("canvas1");
    var ctx1=canvas1.getContext("2d");

    // preload the texture and collar images before starting

    var textureImg,collarImg;
    var imageURLs=[];
    var imagesOK=0;
    var imgs=[];
    imageURLs.push("https://dl.dropboxusercontent.com/u/139992952/stackoverflow/checkered.png");
    imageURLs.push("https://dl.dropboxusercontent.com/u/139992952/stackoverflow/collar.png");
    loadAllImages();

    function loadAllImages(callback){
        for (var i = 0; i < imageURLs.length; i++) {
            var img = new Image();
            img.crossOrigin="anonymous";
            imgs.push(img);
            img.onload = function(){ 
                imagesOK++; 
                if (imagesOK==imageURLs.length ) {
                      textureImg=imgs[0];
                      collarImg=imgs[1];
                      start();
                }
            }; 
            img.src = imageURLs[i];
        }      
    }


    function start(){

        // set both canvas dimensions
        canvas.width=collarImg.width;
        canvas.height=collarImg.height+5;
        canvas1.width=textureImg.width;
        canvas1.height=textureImg.height;

        // draw the textureImg on canvas1
        ctx1.drawImage(textureImg,0,0,canvas1.width,canvas1.height);

        // curve the texture into a collar shaped curved 
        curveTexture(collarImg.width,collarImg.height);

        // draw the collarImg on canvas
        ctx.drawImage(collarImg,0,0);

        // set compositing to source-atop
        // any new drawing will ONLY fill existing non-transparent pixels
        ctx.globalCompositeOperation="source-atop";

        // draw the curved texture from canvas1 onto the collar of canvas
        // (the existing pixels are the collar, so only the collar is filled)
        ctx.drawImage(canvas1,0,0);



    }

    function curveTexture(w,h){

        // define a quadratic curve that fits the collar bottom
        // These values change if the collar image changes (+5,-32)
        var x0=0;
        var y0=h+5;
        var cx=w/2;
        var cy=h-32;
        var x1=w;
        var y1=h+5;

        // get a,b,c for quadratic equation
        // equation is used to offset columns of texture pixels
        // in the same shape as the collar
        var Q=getQuadraticEquation(x0,y0,cx,cy,x1,y1);

        // get the texture canvas pixel data
        // 2 copies to avoid self-referencing
        var imageData0 = ctx1.getImageData(0,0,w,h);
        var data0 = imageData0.data;
        var imageData1 = ctx1.getImageData(0,0,w,h);
        var data1 = imageData1.data;

        // loop thru each vertical column of pixels
        // Offset the pixel column into the shape of the quad-curve
        for(var y=0; y<h; y++) {
          for(var x=0; x<w; x++) {

              // the pixel to write
              var n=((w*y)+x)*4;
              // the vertical offset amount
              var yy=parseInt(y+h-(Q.a * x*x + Q.b*x + Q.c));
              // the offset pixel to read
              var nn=((w*yy)+x)*4;

              // offset this pixel by the quadCurve Y value (yy)
              data0[n+0]=data1[nn+0];
              data0[n+1]=data1[nn+1];
              data0[n+2]=data1[nn+2];
              data0[n+3]=data1[nn+3];
          }
        }
        ctx1.putImageData(imageData0,0,0);
    }


    // Quadratic Curve: given x coordinate, find y coordinate
    function getQuadraticY(x,Q){
        return(Q.a * x*x + Q.b*x + Q.c);
    }

    // Quadratic Curve: 
    // Given: start,control,end points
    // Find: a,b,c in quadratic equation ( y=a*x*x+b*x+c )
    function getQuadraticEquation(x0,y0,cx,cy,x2,y2){
        // need 1 more point on q-curve, so calc its midpoint XY
        // Note: since T=0.5 therefore TT=(1-T)=0.5 also [so could simplify]
        var T=0.50;
        var TT=1-T;
        var x1=TT*TT*x0+2*TT*T*cx+T*T*x2;
        var y1=TT*TT*y0+2*TT*T*cy+T*T*y2;
        var A = ((y1-y0)*(x0-x2) 
              + (y2-y0)*(x1-x0))/((x0-x2)*(x1*x1-x0*x0) 
              + (x1-x0)*(x2*x2-x0*x0));
        var B = ((y1-y0)-A*(x1*x1-x0*x0))/(x1-x0);
        var C = y0-A*x0*x0-B*x0;
        return({a:A,b:B,c:C});
    }


}); // end $(function(){});
</script>

</head>

<body>
    <p>"Curve" a texture by offsetting Y pixels based on Q-curve</p>
    <canvas id="canvas" width=300 height=300></canvas>
    <p>The temporary texture canvas</p>
    <canvas id="canvas1" width=300 height=300></canvas>
</body>
</html>
于 2013-09-16T20:12:09.560 回答
1

您可以对多边形进行三角剖分,然后弯曲网格。然后你可以用图案填充网格。下面是一个 Java 三角剖分的例子:这个 delaunay 三角剖分的代码是如何工作的?. 这是一个三角剖分的例子和一些去除长边的工作。它是一个二维点集的凹壳。

在此处输入图像描述

在此处输入图像描述

于 2013-09-15T10:13:40.190 回答