Category: HTML5

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AngularJS + JQueryMobile and Dynamic Loading of pages

I was experimenting with using AngularJS and JQueryMobile together and loading pages dynamically. The page loading and routing can either be handled by JQueryMobile ($.mobile.pageContainer.pagecontainer(“change”,“page_name”)) or AngularJS. With AngularJS you can use $route service along with ngView and/or use ngInclude .

ngInclude looked easy enough to start with, but did not turn out to be that easy. I will take as simple example of a login application. If user is not logged-in, the app will display the login page and after successfully logging in, the application will display the main page, with the option to logout. Continue reading “AngularJS + JQueryMobile and Dynamic Loading of pages”

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Record and Playback Drawing in HTML5 Canvas – Part II

A reader of my blog post De/Serializing Recordings in Recordable HTML5 Canvas had asked me how to change stroke color and size when recording. I told him that this could be done by adding actions, like setColor and setStrokeSize. For more information about how the recordable canvas was implemented, see my blog post Record and Playback Drawing in HTML5 Canvas . I have updated the example with following new features –

  • Setting stroke color and size – both for drawing and recording
  • Pausing and resuming recording. You may want to pause recording if, for example, you do not want to record time delay when you select stroke color/size. Duration of time that the recording is paused is skipped when playing back the recording.

Here is the demo of how the new features work. Select a color by clicking on any color box on the right side of the canvas. Default selection is black. Currently selected color is displayed in a little bigger box with rounded corner. To select stroke size, I have added a few predefined circles of different sizes on the right side. Currently selected stroke size is displayed in black.

Continue reading “Record and Playback Drawing in HTML5 Canvas – Part II”

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Pre-packaging database with HTML5 Mobile Application

I was discussing with a couple of colleagues of mine yesterday about a HTML5 mobile application that we are developing, and one of the requirements was to pre-package database with the application. A few months back I had created an application that did just that. I thought the solution might be of interest to some of the readers of this blog.

Mobile (or for that matter non-mobile) browsers can create databases for your HTML5 applications. HTML5 provides APIs to create and access the database. But how do you pre-package the database?

The solution is  not really to pre-package the database, but package data that you want a database to initialize with. I don’t think you can really package a SQLite database and ask browser to use it for your HTML5 application. You need to create database and tables when the application is run the first time and then load data packaged with the application. Let’s say we want to create a table called ‘person’ and want to populate this table when the application is run the first time. Continue reading “Pre-packaging database with HTML5 Mobile Application”

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De/Serializing Recordings in Recordable HTML5 Canvas


Last year I blogged about creating a recordable HTML5 Canvas. I explained how to record strokes/drawings created on a HTML5 Canvas and play them back. There are a couple of comments on that post asking me to explain how to save recordings and load them back. Serialization and deserialization of recordings was on my to-do list for a long time and finally this week I got around to implement it. There are different ways to serialize and deserialize recordings, and I have implemented a simple method – using JSON. The serialized data is a bit verbose because of descriptive variable names I have used, but you can change that easily.

RecordableDrawing (in this script file) function remains unchanged. I have added a new file drawingSerializer.js . Two important functions in this file are serializeDrawing and deserializeDrawing.
serializeDrawing takes a RecordableDrawing object as argument and returns JSON string containing array of recordings.
deserializeDrawing takes a String (serialized data) as argument and returns array of Recording objects.

To see how serialization and deserialization works, follow these steps – Continue reading “De/Serializing Recordings in Recordable HTML5 Canvas”

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Sprite Animation Revisited


Last year I had blogged about animating sprite using Kinetic JS.
Code in that post was part of a simple game I had created. So the code specific for animating sprite was explained in snippets. A reader of that post contacted me with a request to provide a complete example. So I created a small demo of sprite animation only. If you are interested, you can download it from here. This demo animates images in the sprite sheet at a fixed location, it does not move the image. So I thought  it would be interesting to add motion to sprite images when they are animated.

First, take a look at the demo. Click on the Walk button to make the person walk. You can stop any time. If the person hits right side wall, then she falls, which is also simulated using sprite animation. I know the ‘walk’ does not look natural, but creating graphics is not my string point and this is the best I could manage.

Walking Speed : (Enter value from 1 to 10)

Continue reading “Sprite Animation Revisited”

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Record and Playback Drawing in HTML5 Canvas

A few months back I had created an application that recorded and played back drawings on HTML5 Canvas. For some time now I wanted to refactor the code in that application and create a reusable ‘component’ from it. Which is what I did this week.

Go ahead and try the demo first – Press ‘Record’ key below and then draw some strokes/lines in the box with the mouse (holding down left button). Once you are done, click Stop button. Click ‘Play’ button to play back the drawing you just drew. You can pause and resume too.

Continue reading “Record and Playback Drawing in HTML5 Canvas”

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Developing Database Applications with WebAppRunner

WebAppRunner is the Eclipse RCP application I created to run web applications as standalone desktop applications. I had explained earlier how this application could be used by creating a demo FileList application. In this post I am going to show how WebAppRunner can be used to create Database applications.

I have created a demo application, SQLiteApp.

Continue reading “Developing Database Applications with WebAppRunner”

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Sprite Animation in HTML5 Canvas with KineticJS

If you want to simulate motion with repeated display of a set of images, where each image correspond to one position in a series of positions in motion, then you can do this easily with sprite. Sprite is individual image in this series of images that constitute motion. The example of sprite is a person walking, where his/her motions of hands and legs are repeated during the walk. However sprite animation is not limited to repeated motion only. You can simulate, for example, explosion of an object, with series of images (sprites), each showing different stages of the explosion.

In my simple HTML5 game, the planet stops moving (and the game ends) when it hits any asteroid or boundaries of the Canvas. I modified it so that the planet explodes when it hits any obstacle. And for this I used Sprites. KineticJS makes animating Sprites very easy. This is how my sprite sheet looks like (sprite sheet is one image that contains small individual sprite images) –

Continue reading “Sprite Animation in HTML5 Canvas with KineticJS”

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Collision Detection in HTML5 2D Games


I wanted to make the Simple HTML5 Game I had created a couple of weeks back a little more interesting. I decided that I would add some obstacles in the way of the moving object. The goal then would be to prevent the moving object from hitting the obstacles and boundaries of the Canvas. This required implementation of collision detection (between moving object and obstacles) logic. If shape of the image is rectangular, then it is easy to detect collision; this is something I had already implemented in the last game, where I checked if the moving object hits any of the four boundaries. But if shape of the image is irregular, then it requires a bit more work to detect collision. But first, try out the modified game below and see how collision detection works –
Continue reading “Collision Detection in HTML5 2D Games”

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JavaScript Graphics Libraries

Last year I was evaluating options for JavaScript graphics libraries for ColdFusion Builder ORM extension. The extension lets you select tables from a datasource and displays it in a browser window. You can them configure relationships, table fields, data types etc and generate CFC code. Here is the screen shot of that extension.

I evaluated SVG and Canvas for graphics/drawing in this extension. However Canvas was not supported in Internet Explorer at that time. SVG was supported on all desktop browsers, but Android browser at that time did support SVG (Android version was 2.2 then) . Since this application was meant to be used on desktop, I decided to go with SVG. Fortunately I came across a very good SVG JavaScript library, RaphaelJS, which made drawing and manipulating shapes in the web page a lot easier. I used JQuery + RaphaelJS together in my application. I used these two libraries for my another extension to monitor CF server memory.
Continue reading “JavaScript Graphics Libraries”

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