Titanic for Android
This library is DEPRECATED, as I don't have time to mainatin it anymore. But feel free to go through the code and copy that into your project, it still does its job.
Titanic is an Android experiment reproducing this effect.
How to use
TitanicTextView to your layout:
To start the animation:
titanic = new Titanic();
You may want to keep track of the titanic instance after the animation is started if you want to stop it.
To stop it:
How does it work?
Titanic is a simple illusion obtained by applying an animated translation on the TextView TextPaint Shader's matrix.
Less quick version
What is a Shader?
A Shader is a class defining spans of colors. It is installed in a Paint. It's usually following a certain strategy, so you have LinearGradient shaders, RadialGradient shaders BitmapShader shaders, etc...
- tile mode: how the shader color spans should be repeated on the x and y axis.
- local matrix: can be used to apply transformations on the shader
Why are you bugging me with these notions?
Well because it is exaclty what we are using in this experiment.
TitanicTextView, we create a BitmapShader containing a wave bitmap.
We set the tile mode to:
TileMode.REPEAT. The bitmap is repeated on the x-axis
Tilemode.CLAMP. The edge colors are repeated outside the bitmap on the y-axis
We have a
maskX and a
maskY variable that will define the position of the shader. So at every
onDraw() we will take in account these values and translate the shader's local matrix at the right position.
We also have a variable
offsetY to make the value maskY usable. So when maskY is equal to 0, the wave is at the center of the view.
How is it animating?
The animation is based on Android Animator API. I am not going to go through that part. Go read the documentation if you need some explanations.
In this experiment there are 2 animations.
- One is moving the wave horizontally from 0 to 200 (the width of the wave bitmap).
- The second one is moving the wave vertically from the bottom half to the top half.
To animate these translations, all we need is to apply an animator on
maskY. The position of the shader's matrix will be updated automatically in
I want more examples
Glad you said that. Go check out Shimmer-android. It's based on the same concept with a
See the sample for a common use of this library.
Copyright 2014 Romain Piel
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