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POFlickering TranslateAnimation/ScaleAnimation on a custom View
 

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  1. POFlickering TranslateAnimation/ScaleAnimation on a custom View
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    <p>I implemented a custom <code>View</code> which applies a custom <code>ScaleAnimation/TranslateAnimation</code> via the <code>getTransformation()</code> of the animation. I.e. the application zooms in to a certain point of a bigger bitmap (the bitmap is bigger than the screen). On higher resolution devices (such as the Samsung Galaxy S3, which is x-hdpi), the zoom (actually scale+translate) process <strong>flickers</strong> and stutters strongly. (More precisely, many <strong>parts</strong> of the image flicker, other parts are OK. E.g. text captions contained in the image flicker.) There is some flickering on other devices too, such as Desire HD. (Note that the custom View is required, because later, I apply other custom animations on it too, but that is irrelevant now.)</p> <p>When the animation starts, the bitmap is zoomed-out (i.e. it is visible from "distance"). The animation zooms in and translates at the same time.</p> <p>I thought the bitmap might be too big (indeed it's not small), but I tried everything with no luck: I put correct versions to hdpi,xhpdi,etc., I also tried with smaller sized bitmaps, I tried downsampling via <code>decodeResource()</code>, but nothing helped.</p> <p>Actually, the custom <code>View</code> contains a custom drawable called <code>MyBackgroundDrawable</code>. The <code>MyBackgroundDrawable</code> class handles the animation and draws the transformed bitmap.</p> <p>This is the code of the <code>onDraw()</code> of the custom <code>View</code>:</p> <pre><code>@Override protected void onDraw(Canvas canvas) { canvas.drawColor(Color.WHITE); mMyBackgroundDrawable.draw(canvas); // my custom Drawable invalidate(); } </code></pre> <p>This is how I load the bitmap:</p> <pre><code>Resources res = context.getResources(); BitmapFactory.Options opt = new BitmapFactory.Options(); opt.inScaled = false; Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.mybackground, opt); Drawable mMyDrBackground = new BitmapDrawable(res, bmp); </code></pre> <p>And this is the <code>draw()</code> method of <code>mMyBackgroundDrawable</code> (i.e. my custom <code>Drawable</code>):</p> <pre><code>@Override public void draw(Canvas canvas) { int sc = canvas.save(); sWorld.reset(); // this is a Matrix if (mMyAnimation!= null) { mMyAnimation.getTransformation(AnimationUtils.currentAnimationTimeMillis(), mTransformation); sWorld = mTransformation.getMatrix(); } sMatrix.reset(); sMatrix.preTranslate(sViewportX / 2, sViewportY / 2); sMatrix.preConcat(sWorld); sMatrix.preConcat(mPosition); canvas.setMatrix(sMatrix); mMyDrBackground .draw(canvas); canvas.restoreToCount(sc); } </code></pre> <p>Actually, <code>mMyAnimation</code> is an <code>AnimationSet</code>, and (while the flickering happens), it is playing a <code>TranslateAnimation+ScaleAnimation</code> (at the same time, because I'm zooming and moving to a certain point of the bitmap at the same time).</p> <p>Why does the flickering and stuttering happen, how can it be solved?</p> <p><strong>UPDATE</strong>: I didn't implement <code>onMeasure()</code> for the custom <code>View</code>. Can this cause such a problem? My custom view is added to this layout (i.e. to <code>layoutRoot</code>):</p> <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" android:id="@+id/layoutRoot" &gt; &lt;/RelativeLayout&gt; </code></pre>
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    1. PTQuestion
    1. USThomas Calc
    1. USThomas Calc
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    1. COIt flickers or jitters?
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      1. POFlickering TranslateAnimation/ScaleAnimation on a custom View
      1. USPrakash Nadar
    2. COI meant *stuttering* like: while zooming, it stops a little bit and then jumps a bit, like slowing down. I meant *flicker* like "visible redraw", so it is like some parts (like texts) on the image will look like redrawn with white-ish color suddenly. I checked the definition of jitter to be able to understand your question: yes, I think the effect can be considered as jitter altogether.
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      1. POFlickering TranslateAnimation/ScaleAnimation on a custom View
      1. USThomas Calc
    3. COI don't know if this information is going to be useful (or accurate), I believe what you doing may not be using the hardware acceleration and so the scaling is done via software and not via hardware acceleration which is cause for the flicker/jitter. Can you do the scaling using the ScaleAnimation altogether?
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      1. POFlickering TranslateAnimation/ScaleAnimation on a custom View
      1. USPrakash Nadar
 

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