Googlebot
Googlebot

Reputation: 15673

How to make a jQuery function for html5 canvas

Consider a simple canvas as

$(document).ready(function(){
draw();
});
    function draw() {  
      var canvas = document.getElementById("canvas");  
      if (canvas.getContext) {  
        var ctx = canvas.getContext("2d");  

        ctx.fillStyle = "rgb(200,0,0)";  
        ctx.fillRect (10, 10, 55, 50);  

        ctx.fillStyle = "rgba(0, 0, 200, 0.5)";  
        ctx.fillRect (30, 30, 55, 50);  
      }  
    }

How can I introduce variable into the jQuery function to draw several canvases with defined variable (e.g. color set).

In fact, I want to replace canvas id and its options (like color) with variable provided by draw(variables), e.g.draw(canvas_id, color, ...).

Example: (for creating several canvases on different DOM elements)

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

        ctx.fillStyle = "rgb(200,0,0)";  
        ctx.fillRect (10, 10, 55, 50);  

        ctx.fillStyle = "rgba(0, 0, 200, 0.5)";  
        ctx.fillRect (30, 30, 55, 50);  
      }  
    } 

draw(canvas1);
draw(canvas2);

Upvotes: 2

Views: 1473

Answers (2)

Neil
Neil

Reputation: 8111

Here is one way you could do it:

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

      for(var i=0; i < colors.length; i ++){
          ctx.fillStyle = colors[i];  
          ctx.fillRect (10*i, 10*i, 55, 50);
      } 
  }  
}

// define some colors in an array
var colors = ["rgb(200,0,0)","rgba(0, 0, 200, 0.5)","rgba(0, 128, 200, 0.5)"];

draw(colors);

EDIT

Here is jsfiddle example

Upvotes: 1

Ram
Ram

Reputation: 144659

try this:

function draw(id, clr, fill) {  
      var canvas = document.getElementById(id);  
      if (canvas.getContext) {  
        var ctx = canvas.getContext("2d");  

        ctx.fillStyle = clr;  
        ctx.fillRect (fill);  

      }  
    }

Upvotes: 1

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