Tag Archives: canvas example

Rotate object or shape in HTML5 Canvas

HTML5 canvas provides rotate(angle) method which is used to rotate the canvas around the current origin clockwise. The parameter ‘angle’ should be radians not in degrees. You can use degree * Math.PI/180 formula to convert the degree in radians, suppose if you want to rotate canvas 45 degree you can use 45*Math.PI/180 for the angle. Continue reading Rotate object or shape in HTML5 Canvas

Set size of an image in the HTML5 canvas

The canvas size and image size both are different things. The canvas is the DOM element in the HTML5 that allows drawing the 2D shapes and bitmap images. To draw the image on the canvas, it should be checked that what the dimensions of the loaded image is, and if the original image’s height and width are greater than the canvas’s height and width, Continue reading Set size of an image in the HTML5 canvas

Invert image using the HTML5 canvas

In HTML5 canvas’s 2D context support three methods that can draw pixel by pixel: createImageData, getImageData, and putImageData. With the help of these methods you can filtering the image on the canvas such as inversion of the image. The following code section will show you that how can you invert the image on canvas. Continue reading Invert image using the HTML5 canvas

Draw Text on canvas in HTML5

 
You can draw the text on the HTML5 canvas, for it we use the following JavaScript method:
 
fillText(text, x, y [,maxWidth]) method fills the text in the current fill style.
strokeText(text, x, y [,maxWidth]) method outlines the text in the current stroke style.
 

Both methods uses the following arguments:

text: The text to draw into the context.
x: The X coordinate at which to begin drawing.
y: The Y coordinate at which to begin drawing.
maxWidth(Optional): the maximum width to draw.
 
we use the font property of the canvas context to set the font of the drawn text that will contains the font style, size, and family name.
 


Draw text on canvas html5

 

Example

The following example will draw the string ‘Welcome’ on the canvas.

<html>
<head>
  <title>Draw text</title>
    <style type="text/css">
        #MyCanvas {border:1px solid black;}
    </style>
  <script type="text/javascript">
      function drawText() {
          var ctx;
          var canvas = document.getElementById("MyCanvas");
          if (canvas.getContext) {
              ctx = canvas.getContext("2d");
              ctx.font = "15pt verdana";
              ctx.fillText("Welcome", 100, 100);
          }
      }
  </script>
</head>
<body onload="drawText();">
  <canvas id="MyCanvas" width="350" height="200">
  This browser or document mode doesn't support canvas object</canvas>
 </body>
</html>