Transcript Graphics & Animation in Android Android rendering options • • • • The Canvas API Renderscript OpenGL wrappers NDK OpenGL http://graphics-geek.blogspot.com/2011/06/android-rendering-options.html.

Graphics & Animation
in Android
Android rendering options
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The Canvas API
Renderscript
OpenGL wrappers
NDK OpenGL
http://graphics-geek.blogspot.com/2011/06/android-rendering-options.html
The Canvas API
• Standard rendering for a typical SDK
application that uses View objects (standard
and custom)
• consists of calls to each View's
onDraw() method. This method takes a single
parameter, Canvas, which is the object used
by the view to draw its content.
http://graphics-geek.blogspot.com/2011/06/android-rendering-options.html
Renderscript
• Introduced in Android 3.0
• API targeted high-performance 3D rendering and
compute operations
• a 3D rendering API on top of hardware
acceleration, language C99
• executing native code on the device still crossplatform
• use of extensions that are placed into the
application package
http://graphics-geek.blogspot.com/2011/06/android-rendering-options.html
Renderscript
• Live Wallpapers, the video wall view in the
YouTube application, and the Books
application (including that beautiful page-turn
effect).
• http://www.youtube.com/watch?v=uQ5NumRfHN4
http://graphics-geek.blogspot.com/2011/06/android-rendering-options.html
Open GL Wrappers
• OpenGL APIs at the SDK level
• not a recommended practice as a general
approach for complex scenes that require
high-performance graphics
• difficult to achieve high performance levels
equivalent to native access to OpenGL due to
the overhead of calling down from the SDK
• Music application that shipped with Android
3.0 used this approach
http://graphics-geek.blogspot.com/2011/06/android-rendering-options.html
NDK OpenGL
• no access to the View objects, or the events,
or the rest of the infrastructure that is
provided in the SDK APIs
• graphics environment sufficient for some
specific purposes: game developers
• compiles applications to specific CPU
architectures
http://graphics-geek.blogspot.com/2011/06/android-rendering-options.html
Animations
• Animations prior to Android 3.0
– android.view.animation
– move, scale, rotate, and fade Views
– combine multiple animations together in
an AnimationSet
– specify animations in a LayoutAnimationController
to get automatically staggered animation
– use Interpolator implementations like
AccelerateInterpolator and Bounce to get natural,
nonlinear timing behavior
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
Animations
• Animations prior to Android 3.0
– you can animate Views... and that's it
– How to animate the position of a Drawable in a
custom drawing? Or translucency?
– you can move, rotate, scale, and fade a View... and
that's it.
– animating the background color of a View?
– hard-coded set of things they were able to do, and
you could not make them do anything else.
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
Animations
• Animations in Android 3.0
– not specific to Views
– animates values over time
– assigning those values to any target objects and
properties
• http://www.youtube.com/watch?feature=play
er_embedded&v=-9nxx066eHE#!
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
Animations
• Animator
– superclass for classes which provide basic support
for animations which can be started, ended, and
have AnimatorListeners added to them
java.lang.Object
↳
android.animation.Animator
↳
android.animation.AnimatorSet
java.lang.Object
↳ android.animation.Animator
↳ android.animation.ValueAnimator
↳ android.animation.ObjectAnimator
Animations
• AnimatorSet
– choreograph multiple animators together into a
single animation
– animations can be set up to play together, in
sequence, or after a specified delay
– “It is possible to set up a AnimatorSet with circular
dependencies between its animations… results of
this configuration are undefined… circular
dependencies should be avoided”
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
Animations
• ValueAnimator
– runs the internal timing loop that causes all of a
process's animations to calculate and set values
– two pieces to animating properties: calculating
the animated values and setting those values on
the object and property in question.
ValueAnimator takes care of the first part;
calculating the values
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
Animations
• ObjectAnimator
– takes care of the second part : setting animating
values on the object and property
– main class in the new animation system
ObjectAnimator.ofFloat(myObject, "alpha", 0f).start();
public void setAlpha(float value);
public float getAlpha();
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
Animations
• View properties
– added new properties to the View class in
Honeycomb
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translationX and translationY
rotation, rotationX, and rotationY
scaleX and scaleY
pivotX and pivotY
x and y
alpha
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
Animations
• AnimatorSet
– choreograph multiple animations
ObjectAnimator fadeOut = ObjectAnimator.ofFloat(v1, "alpha", 0f);
ObjectAnimator mover = ObjectAnimator.ofFloat(v2, "translationX", 500f, 0f);
ObjectAnimator fadeIn = ObjectAnimator.ofFloat(v2, "alpha", 0f, 1f);
AnimatorSet animSet = new
AnimatorSet().play(mover).with(fadeIn).after(fadeOut);
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html
Animations
• TypeEvaluator
– The system knows how to
animate float and int values, but otherwise it needs
some help knowing how to interpolate between the
values you give it
– add this interface to the ValueEvaluator
Interface TypeEvaluator {
public abstract T evaluate (float fraction, T startValue, T endValue)
}
http://android-developers.blogspot.com/2011/02/animation-in-honeycomb.html