Canvas Horizontal and Vertical Drag Using HTML 5

Deepak Dwij
Mar 24, 2012
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Article

Introduction

In this article we are going to understand horizontal and vertical dragging using the HTML 5 canvas. In this section, drag and drop the the yellow rectangle and observe that it can only move horizontally. Drag and drop the white rectangle and observe that it can only move vertically while the application is running in the browser.

Here we will use some JavaScript and some styles along with HTML code. Just go through the steps to see how to create this application.

Let's see how the horizontal and vertical Drag application can be created. To do so use the following steps.

Step 1 : Open a HTML editor or Visual Studio.

Open File menu ->select new ->Choose Website then.

This is where we will create the HTML5 application.

Go to Solution Explorer
Right-click on the Application name
Select Add-->add new item
Now in the window that opens, select an HTML page or new Web form
Rename it to HandVDrag.aspx

Step 2 : In this section we will create the style for the media and create the .css on the media screen. Put the given script in the Head section of the HTML or between the <head>--</head> tags. Here the CSS is used for design purposes.

CSS Script

<style>
body
{
  margin: 0px;
  padding: 0px;
}
Canvas
{
   border: 2px solid #9C9898;
   margin-top: 50px;
   margin-left: 50px;
   background-color: #009999;
   box-shadow: 5px 5px 8px #222;
}
.title
{
   text-align: center;
   font-family: Segoe UI Light, Arial, Helvetica;
   font-size: 2.2em;
   margin: 1em;
}
.info
{
   text-align: center;
   font-family: Segoe UI Light, Arial, Helvetica;
   font-size: 1.2em;
   margin: 0.25em;
}
</style>

Step 3 : In this part we need to work on some JavaScript. To fully understand how JavaScript works, download the attached .rar file and run the horizontal and vertical Drag application.

The whole JavaScript looks as in the following:

window.onload = function ()
{

var stage = new Kinetic.Stage("container", 578, 200);

var layer = new Kinetic.Layer();

var rectHeight = 50;

var rectWidth = 100;

var rectY = (stage.height - rectHeight) / 2;

var hbox = new Kinetic.Text({

x: 120,

y: 70,

fill: "yellow",

strokeWidth: 4,

fontSize: 18,

fontFamily: "Calibri",

text: "Horizontal",

textFill: "red",

padding: 15,

draggable: true,

dragConstraint: "horizontal"

});

var vbox = new Kinetic.Text({

x: 350,

y: 70,

fill: "white",

strokeWidth: 4,

draggable: true,

fontSize: 18,

fontFamily: "Calibri",

text: "Vertical",

textFill: "red",

padding: 15,

draggable: true,

dragConstraint: "vertical"

});

layer.add(hbox);

layer.add(vbox);

stage.add(layer);

};
</script>

Step 4 : In this section we are going to become familiar with the body part of HTML scripting. Replace this script from the body section of the HandVDrag.aspx page. Here we pass a Canvas in the canvas tag.

<body style="background-color: #33CCFF">
    <center>
        <h2>
            Canvas Horizontal and vertical Drag
        </h2>
    </center>
    <hr />
    <div id="container">
    </div>
</body>

Step 5 : The complete code for the horizontal and vertical Drag application:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="HandVDrag.aspx.cs" Inherits="horizontal_and_vertical_Drag.HandVDrag" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <style>
    </style>
    <script src="jscript.js"></script>
    <script>
    </script>
</head>
<body style="background-color: #33CCFF">
    <center>
        <h2>
            Canvas Horizontal and vertical Drag
        </h2>
    </center>
    <hr />
    <div id="container">
    </div>
</body>
</html>

Step 6 : Output Press F5

Note : For the accurate output of HTML5 applications, you must have the Google Chrome browser in your PC. Drag and drop the the yellow rectangle and observe that it can only move horizontally. Drag and drop the white rectangle and observe that it can only move vertically while the application is running in the browser.

When you drag the yellow rectangle the position of rectangle changes only horizontally.

When you drag the white rectangle the position of rectangle changes only vertically.

Here are the some useful resources.