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I want to wrap an image around a cylindrical object like mugs in a web app, like so

Mug with personalised image

This will likely be a base image (e.g. a jpeg image of a mug) containing a transformed image of a user uploaded image.

There seems to be a lot of resources on this in PhotoShop. However, this is of course not appropriate for web, mobile or server environments.

I also know this is possible, as a number of sites already do this extremely well. For example, Vista Print (see image), Asda Photos (and loads more on the internet by just searching personalised mugs on Google), using what seems to be just HTML5.

However, bizarley I cannot seem to find any answers for a Web App. There's a lot of questions on this in StackOverflow that are all unanswered like: Wrap an image around a cylinder, wrap image around a cylindrical cup using html 5 canvas and javascript, How overlay image over a cup using html5 canvas and many many more!

Therefore can someone please finally provide an answer to this question.

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Yahya Uddin
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  • Why the downvote? – Yahya Uddin Dec 06 '16 at 14:16
  • Possible duplicate of [Image manipulation and texture mapping using HTML5 Canvas?](http://stackoverflow.com/questions/4774172/image-manipulation-and-texture-mapping-using-html5-canvas) – 6502 Dec 06 '16 at 14:17
  • @6502 I think this is very different to the actual question being asked. That question deals with texture mappings, and does not even go into wrapping an image around another object. – Yahya Uddin Dec 06 '16 at 14:24
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    Use webGL and Three.js. Or you can use the 2D canvas and just slice the image into 1 pixel wide strips. Then map them around `sin(ang)*tilt` for the y position and `cos(ang)*mugRadius` for the x position. Add to `ang` the amount the mug has rotated for each image to match mug rotation. And you know not to draw a strip if `sin(ang) < 0` – Blindman67 Dec 06 '16 at 14:47
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    @YahyaUddin: texture mapping is the very technique of wrapping images around general (even non-developable) surfaces. Of course if you need to handle onlly a specific surface then a "fake" solution is probably a better choice. – 6502 Dec 06 '16 at 17:08
  • @6502 Oh that makes sense. However, what do you mean by "fake solution" and how would you do it? – Yahya Uddin Dec 06 '16 at 17:29
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    I have a script to do something similar using ImageMagick. See http://www.fmwconcepts.com/imagemagick/cylinderize/index.php – fmw42 Feb 23 '18 at 19:17
  • fmw42 - the script takes me 50 sec to create 36 jpg. nothing I can use. I'm using a high end machine – Kulpemovitz Mar 13 '18 at 08:33

2 Answers2

19

Simple cylinder wrap with Canvas 2D

Very simple example using sin and cos to create the curved map. The images is cut into strips approx 1 pixel wide then rendered as half a squashed circle. As perspective is a linear effect related to distance I also add a small amount of perspective by scaling up in the y direction depending on sin(angle) (where angle = 0 on the left Math.PI / 2 at the forward center).

These two demos are animated just to show that it is not a slow process, but compared to webGL it is a snail. If you use such a method, don't make it realtime or you will chew up the batteries of mobile devices. Realtime 3D should be done with webGL

Basic wrap

var createImage=function(w,h){var i=document.createElement("canvas");i.width=w;i.height=h;i.ctx=i.getContext("2d");return i;}

var canvas = createImage(400,400);
var ctx = canvas.ctx;
document.body.appendChild(canvas)
ctx.clearRect(0,0,500,500)
var image = createImage(400,200);
image.ctx.font = "60px arial";
image.ctx.textAlign = "center";
image.ctx.fillStyle = "#7F5";
image.ctx.fillRect(0,0,image.width,image.height)
image.ctx.fillStyle = "white";
image.ctx.fillText("Wrap around",200,60)
image.ctx.fillText("Some images",200,140)


function draw(ang,tilt, perspective){
    var step = 1/(Math.max(image.width,400));
    for(var i = 0; i < 1; i += step){
        var a = i * Math.PI;
        var a1 = (i+ step*2) * Math.PI ;
        var ix = i * image.width*1.2;
        var iw = step * image.width*1.2;
        a += ang * Math.PI * 2;
        a1 += ang * Math.PI * 2;
        a = Math.PI -a;
        a1 = Math.PI -a1;
        var x = canvas.width * 0.5;
        var y = canvas.height * 0.1;
        
        var x1 = x + Math.cos(a1) * 110;
        var y1 = y + Math.sin(a) * tilt;
        x += Math.cos(a) * 110;
        y += Math.sin(a) * tilt;
        var s = Math.sin(a);
        var s1 = Math.sin(a1);
        if(s > 0 || s1 > 0){
            ctx.drawImage(image,ix,0,iw,image.height,x1,y- s * perspective*0.5,x-x1,200 + s * perspective)
        }
        
        
    }
}
var w = canvas.width;
var h = canvas.height;




// main update function
function update(timer){
    ctx.setTransform(1,0,0,1,0,0); // reset transform
    ctx.globalAlpha = 1;           // reset alpha
    ctx.fillStyle = "black"
    ctx.fillRect(0,0,w,h);
    draw(timer / 2000, 40,30)
    requestAnimationFrame(update);
}
requestAnimationFrame(update);

Add lighting.

To extend it a little further you can add overlays to do lighting. I could not find a public domain image of a white cup so I used the same function to render the lighting (A few simple gradients) onto and image. Then for the final output I render the overlay as a backing image, then the text, then two passes again with the shading image, first darken with "multiply", then a soft highlight with "lighten"

var createImage=function(w,h){var i=document.createElement("canvas");i.width=w;i.height=h;i.ctx=i.getContext("2d");return i;}

var canvas = createImage(400,400);
var ctx = canvas.ctx;
document.body.appendChild(canvas)
ctx.clearRect(0,0,500,500)
var image = createImage(400,200);
image.ctx.font = "60px arial";
image.ctx.textAlign = "center";
image.ctx.fillStyle = "#999";
image.ctx.fillRect(0,10,image.width,image.height-20)
image.ctx.fillStyle = "white";
image.ctx.fillText("Wrap around",200,60)
image.ctx.fillText("Some images",200,140)

//---------------------------------------------------------------------
// create shading map
var shading = createImage(400,200);
// left to right shading
var g1 = shading.ctx.createLinearGradient(0,0,400,0);
g1.addColorStop(0,"rgba(245,245,245,1)");
g1.addColorStop(0.05,"rgba(255,255,255,1)");
g1.addColorStop(0.5,"rgba(230,230,230,1)");
g1.addColorStop(0.95,"rgba(255,255,255,1)");
g1.addColorStop(1,"rgba(245,245,245,1)");
shading.ctx.fillStyle = g1;
shading.ctx.fillRect(0,0,400,200);

// bottom to top shading
var g = shading.ctx.createLinearGradient(0,0,0,200);
g.addColorStop(1,"rgba(200,200,200,1)");
g.addColorStop(0.95,"rgba(200,200,200,0.4)");
g.addColorStop(0,"rgba(255,255,255,0.0)");
shading.ctx.globalCompositeOperation = "multiply";
shading.ctx.fillStyle = g;
shading.ctx.fillRect(0,0,400,200);


var g = shading.ctx.createRadialGradient(0,-100,100,0,-100,200);
g.addColorStop(0,"rgba(200,200,200,1)");
g.addColorStop(0.95,"rgba(255,255,255,1)");
g.addColorStop(1,"rgba(255,255,255,0)");
shading.ctx.fillStyle = g;
shading.ctx.globalCompositeOperation = "screen";
shading.ctx.setTransform(1.4,0,0,1,200,0);
shading.ctx.beginPath();
shading.ctx.arc(0,-100,200,0,Math.PI * 2);
shading.ctx.globalAlpha = 0.5;
shading.ctx.fill();
shading.ctx.setTransform(1,0,0,1,0,0);
shading.ctx.fillStyle = g1;
shading.ctx.fillRect(0,0,400,200);

var overlay = createImage(400,400);
draw(shading,overlay.ctx,0, 40,30,110,200,1);

function draw(image,ctx,ang,tilt, perspective, width, height,stretch){
    var step = 1/(Math.max(image.width,400));
    for(var i = 0; i < 1; i += step){
        var a = i * Math.PI;
        var a1 = (i+ step*2) * Math.PI ;
        var ix = i * image.width*stretch;
        var iw = step * image.width*stretch;
        a += ang * Math.PI * 2;
        a1 += ang * Math.PI * 2;
        a = Math.PI -a;
        a1 = Math.PI -a1;
        var x = canvas.width * 0.5;
        var y = canvas.height * 0.1;
        
        var x1 = x + Math.cos(a1) * width;
        var y1 = y + Math.sin(a) * tilt;
        x += Math.cos(a) * width;
        y += Math.sin(a) * tilt;
        var s = Math.sin(a);
        var s1 = Math.sin(a1);
        if(s > 0 || s1 > 0){
            ctx.drawImage(image,ix,0,iw,image.height,x1,y- s * perspective*0.5,(x-x1-1),height + s * perspective)
        }
        
        
    }
}
var w = canvas.width;
var h = canvas.height;

// main update function
function update1(timer){
    ctx.setTransform(1,0,0,1,0,0); // reset transform
    ctx.globalAlpha = 1;           // reset alpha
    ctx.fillStyle = "black"
    ctx.fillRect(0,0,w,h);
    ctx.drawImage(overlay,0,0);
    draw(image,ctx,timer / 4000, 40,30,110,200,1)
    ctx.globalCompositeOperation = "multiply";
    ctx.drawImage(overlay,0,0);
    ctx.globalAlpha = 0.2
    ctx.globalCompositeOperation = "lighten";
    ctx.drawImage(overlay,0,0);
    ctx.globalCompositeOperation = "source-over";
    requestAnimationFrame(update1);
}

 requestAnimationFrame(update1);
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Blindman67
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  • Wow that looks amazing. Definitely heading me to the right track! – Yahya Uddin Dec 06 '16 at 15:46
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    @YahyaUddin I realise you would want some lighting effects as well. So I have added another example showing how that can be done in 2D and using composite operations. – Blindman67 Dec 07 '16 at 05:29
18

enter image description here

function canvas1() {
  var canvas = document.getElementById("canvas1");
  var ctx = canvas.getContext("2d");

  var productImg = new Image();
  productImg.onload = function() {
    var iw = productImg.width;
    var ih = productImg.height;
    console.log("height");

    canvas.width = iw;
    canvas.height = ih;

    ctx.drawImage(productImg, 0, 0, productImg.width, productImg.height,
      0, 0, iw, ih);
    loadUpperIMage()
  };

  productImg.src = "http://res.cloudinary.com/pussyhunter/image/upload/c_scale,f_auto,h_350/left_handle_cup_i7ztfs.jpg"


  function loadUpperIMage() {
    var img = new Image();


    img.src = "http://res.cloudinary.com/pussyhunter/image/upload/v1488184107/500_F_97150423_M13q2FeAUZxxIx6CaPixHupprmyiVVli_skh6fe.jpg"
    img.onload = function() {

      var iw = img.width;
      var ih = img.height;

      var xOffset = 102, //left padding
        yOffset = 110; //top padding

      //alert(ih)
      var a = 75.0; //image width
      var b = 10; //round ness

      var scaleFactor = iw / (4 * a);

      // draw vertical slices
      for (var X = 0; X < iw; X += 1) {
        var y = b / a * Math.sqrt(a * a - (X - a) * (X - a)); // ellipsis equation
        ctx.drawImage(img, X * scaleFactor, 0, iw / 9, ih, X + xOffset, y + yOffset, 1, 174);
      }
    };
  }

};

function canvas2() {

  var canvas = document.getElementById("canvas2");
  var ctx = canvas.getContext("2d");

  var productImg = new Image();
  productImg.onload = function() {
    var iw = productImg.width;
    var ih = productImg.height;
    console.log("height");

    canvas.width = iw;
    canvas.height = ih;

    ctx.drawImage(productImg, 0, 0, productImg.width, productImg.height,
      0, 0, iw, ih);
    loadUpperIMage()
  };


  productImg.src = "http://res.cloudinary.com/pussyhunter/image/upload/h_350/canter_handle_cup_xyxhdd.jpg"

  function loadUpperIMage() {
    var img = new Image();

    img.src = "http://res.cloudinary.com/pussyhunter/image/upload/v1488184107/500_F_97150423_M13q2FeAUZxxIx6CaPixHupprmyiVVli_skh6fe.jpg"

    img.onload = function() {

      var iw = img.width;
      var ih = img.height;

      // alert(iw)

      var xOffset = 101, //left padding
        yOffset = 110; //top padding

      var a = 75.0; //image width
      var b = 10; //round ness

      var scaleFactor = iw / (4 * a);

      // draw vertical slices
      for (var X = 0; X < iw; X += 1) {
        var y = b / a * Math.sqrt(a * a - (X - a) * (X - a)); // ellipsis equation
        ctx.drawImage(img, X * scaleFactor, 0, iw / 3, ih, X + xOffset, y + yOffset, 1, 174);

      }
    };
  }

};

function canvas3() {

  var canvas = document.getElementById("canvas3");
  var ctx = canvas.getContext("2d");

  var productImg = new Image();
  productImg.onload = function() {
    var iw = productImg.width;
    var ih = productImg.height;

    canvas.width = iw;
    canvas.height = ih;

    ctx.drawImage(productImg, 0, 0, productImg.width, productImg.height,
      0, 0, iw, ih);
    loadUpperIMage()
  };

  productImg.src = "http://res.cloudinary.com/pussyhunter/image/upload/h_350/right_handle_cup_dsdhr7.jpg"


  function loadUpperIMage() {
    var img = new Image();

    img.src = "http://res.cloudinary.com/pussyhunter/image/upload/v1488184107/500_F_97150423_M13q2FeAUZxxIx6CaPixHupprmyiVVli_skh6fe.jpg"

    img.onload = function() {

      var iw = img.width;
      var ih = img.height;

      //alert(iw)

      var xOffset = 102, //left padding
        yOffset = 110; //top padding

      var a = 75.0; //image width
      var b = 10; //round ness

      var scaleFactor = iw / (3 * a);

      // draw vertical slices
      for (var X = 0; X < iw; X += 1) {
        var y = b / a * Math.sqrt(a * a - (X - a) * (X - a)); // ellipsis equation
        ctx.drawImage(img, X * scaleFactor, 0, iw / 1.5, ih, X + xOffset, y + yOffset, 1, 174);
      }
    };
  }

};

setTimeout(function() {
  canvas1()
}, 1000);
setTimeout(function() {
  canvas2()
}, 2000);
setTimeout(function() {
  canvas3()
}, 3000);
<!DOCTYPE html>
<html>

<head>
  <script data-require="jquery@*" data-semver="2.1.4" src="http://code.jquery.com/jquery-2.1.4.min.js"></script>
  <link rel="stylesheet" href="style.css" />

  <script src="script.js"></script>
</head>

<body>

  <div>
    <canvas id="canvas1"></canvas>
  </div>

  <div>
    <canvas id="canvas2"></canvas>
  </div>

  <div>
    <canvas id="canvas3"></canvas>
  </div>


</body>

</html>

Note : Just Use these points to calibrate

var scaleFactor = iw / (4*a); //EDIT 4*a TO 6*a

ctx.drawImage(img, X * scaleFactor, 0, iw/3, ih, X + xOffset, y + yOffset, 1, 174); //EDIT  iw/3 TO iw/4
vijay
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