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# HTML5 Canvas - Drawing Lines

# Line Methods:

There are following methods required to draw lines on the canvas:

SN | Method and Description
--- | ---
1 | beginPath() This method resets the current path.
2 | moveTo(x, y) This method creates a new subpath with the given point.
3 | closePath() This method marks the current subpath as closed, and starts a new subpath with a point the same as the start and end of the newly closed subpath.
4 | fill() This method fills the subpaths with the current fill style.
5 | stroke() This method strokes the subpaths with the current stroke style.
6 | lineTo(x, y) This method adds the given point to the current subpath, connected to the previous one by a straight line.

# Example:

Following is a simple example which makes use of above mentioned methods to draw a triangle.

    <!DOCTYPE HTML>
    <html>
    <head>
    <script type="text/javascript">
    function drawShape(){
      // get the canvas element using the DOM
      var canvas = document.getElementById('mycanvas');

      // Make sure we don't execute when canvas isn't supported
      if (canvas.getContext){

        // use getContext to use the canvas for drawing
        var ctx = canvas.getContext('2d');

        // Filled triangle
        ctx.beginPath();
        ctx.moveTo(25,25);
        ctx.lineTo(105,25);
        ctx.lineTo(25,105);
        ctx.fill();

        // Stroked triangle
        ctx.beginPath();
        ctx.moveTo(125,125);
        ctx.lineTo(125,45);
        ctx.lineTo(45,125);
        ctx.closePath();
        ctx.stroke();

      } else {
        alert('You need Safari or Firefox 1.5+ to see this demo.');
      }
    }
    </script>
    </head>
    <body onload="drawShape();">
       <canvas id="mycanvas"></canvas>
    </body>
    </html>

The above example would draw following shape:

To learn above concept - Do Online Practice using latest version of either Safari or Opera.

# Line Properties:

There are several properties which allow us to style lines.

SN | Property and Description
--- | ---
1 | lineWidth [ = value ] This property returns the current line width and can be set, to change the line width.
2 | lineCap [ = value ] This property returns the current line cap style and can be set, to change the line cap style. The possible line cap styles are butt, round, and square
3 | lineJoin [ = value ] This property returns the current line join style and can be set, to change the line join style. The possible line join styles are bevel, round, and miter.
4 | miterLimit [ = value ] This property returns the current miter limit ratio and can be set, to change the miter limit ratio.

# Example:

Following is a simple example which makes use of lineWidth property to draw lines of different width.

    <!DOCTYPE HTML>
    <html>
    <head>
    <script type="text/javascript">
    function drawShape(){
      // get the canvas element using the DOM
      var canvas = document.getElementById('mycanvas');

      // Make sure we don't execute when canvas isn't supported
      if (canvas.getContext){

        // use getContext to use the canvas for drawing
        var ctx = canvas.getContext('2d');

        for (i=0;i<10;i++){
           ctx.lineWidth = 1+i;
           ctx.beginPath();
           ctx.moveTo(5+i*14,5);
           ctx.lineTo(5+i*14,140);
           ctx.stroke();
        }
      } else {
        alert('You need Safari or Firefox 1.5+ to see this demo.');
      }
    }
    </script>
    </head>
    <body onload="drawShape();">
       <canvas id="mycanvas"></canvas>
    </body>
    </html>

The above example would draw following shape:

To learn above concept - Do Online Practice using latest version of either Safari or Opera.

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