EaselJS Pixel Perfect Collision Detection for Bitmaps with Alpha Threshold

Posted on December 20, 2012 by olsn

I just finished the first version of a pixel perfect collision detection for EaselJS Bitmaps and BitmapAnimations.
Get it from Github: https://github.com/olsn/Collision-Detection-for-EaselJS

Here is an example (play around with the alpha threshold and toggle the detection mode):

// Rect Collision
var intersection = ndgmr.checkRectCollision(bitmap1,bitmap2);
// intersection is null if no collision, otherwise a {x,y,width,height}-Object is returned

// Pixel Perfect Collision
var collision = ndgmr.checkPixelCollision(bitmap1,bitmap2,alphaThreshold);
// true or false
// alphaThreshold default is 0, set to higher value to ignore collisions with semi transparent pixels

// Rect Collision

var intersection = ndgmr.checkRectCollision(bitmap1,bitmap2);

// intersection is null if no collision, otherwise a {x,y,width,height}-Object is returned

// Pixel Perfect Collision

var collision = ndgmr.checkPixelCollision(bitmap1,bitmap2,alphaThreshold);

// true or false

// alphaThreshold default is 0, set to higher value to ignore collisions with semi transparent pixels

Removing Ads from Windows8 Apps

Posted on November 26, 2012 by olsn

Two days ago I upgraded to Windows8 (Thank you Microsoft for your MSDNAA Platform!)
And to my suprise I actually like it a lot, especially the ease of installing applications through the Windows 8 Store. However what I didn’t like was that most free apps feature ads now, it’s pretty much: “Buy the app or get annoyed by ads!”
For this article I will be using the Windows8 version of the twitter-client named “metrotwit” – sorry to the folks at Pixel Tucker for using your app to illustrate this ‘issue’! But metrotwit is a great, beautiful and slick looking client and I can only recommend using it!
[Edit: I do admit that my original intention was to see if I could remove ads, but this article is not supposed to just show how to remove ads, it’s more like a call for attention that the new system is not secure at all by illustrating the ease of modifying (almost) any app!]

So I did a little searching to see if I could locate the app and modify it, those were my steps how I removed the ads:

Continue reading →

iOS html5 performance issues #2: scrollpanes and hardware acceleration

Posted on November 13, 2012 by olsn

Don’t try to force hardware acceleration on elements that are placed on a touch-scroll-pane! …and here’s why:

I personally love the ‘-webkit-overflow-scrolling: touch’-feature as it allows you to implement a scroll pane for mobile devices with just writing two lines of css and no need of hasseling around with JS to make some content scroll smooth ect., however this approach also comes with a drawback: hardware acceleration will cause performance-issues on iOS (maybe other mobile devices, though it was only tested on an iPad2 running iOS6)

In my last post I was writing about forcing html5 hardware acceleration on iOS6, turns out you do NOT want to do that on every element as this can also cause the performance to drop, pointed out by the following example:
Continue reading →

iOS6 html hardware acceleration changes and how to fix them

Posted on September 30, 2012 by olsn

As probably many developers have already experience this over the past weeks:
I had a phonegap application for iOS that contained some visually animated components (a coverflow or a carousel for example). But after updating to iOS6 this is all flickring now and it feels horrible because it’s just stumbling and faltering on the new version of the OS.
There are several reasons for this and I cannot say which were already there in iOS5, however here are the two main reasons and instructions on how to fix that: Continue reading →

Coming up with new App ideas

Posted on September 13, 2012 by olsn

Here are some thoughts on the current App ‘situation’ and how the next generation of apps might or could look like by taking ideas from old/bad apps:
(NOTE: In this article I am NOT talking about Games or Gaming Apps, for those it looks kind of different)

Let’s face it: “There is an app for everything!” – However looking at the two major App Stores, iTunes and Play, there are serveral types of apps.
Now the division of those apps are not backed by any statistics and are only based on my perception of the appstores and my experience browsing through the stores:

Type	Description	Percentage
A Apps	Quality/Polished Apps, developed by backed/bigger companies	20%
B Apps	Niche Apps by ‘small’ developers/indie devs that do generate some revenue	15%
C Apps	Innovative/Useful Apps that are either unknown or badly executed	20%
D Apps	‘Crappy’ Apps that are either badly executed, a bad copy of another A-App or have just no real use whatsoever	45%

Continue reading →

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Author Archives: olsn

EaselJS Pixel Perfect Collision Detection for Bitmaps with Alpha Threshold

Removing Ads from Windows8 Apps

iOS html5 performance issues #2: scrollpanes and hardware acceleration

iOS6 html hardware acceleration changes and how to fix them

Coming up with new App ideas