Android: transform image using a Matrix

Question

I'm looking to transform an image using a Matrix on the onDraw method of a custom class I created which extends ImageView e.g.,

@Override
public void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.save();
    canvas.setMatrix(imageMatrix);
    canvas.drawBitmap(((BitmapDrawable)mIcon).getBitmap(), imageMatrix, null);
    canvas.restore();
}

However, what I coded above does not really work. How exactly do I apply the imageMatrix on the canvas? Thanks!

a.ch. · Accepted Answer · 2012-01-18 07:33:23Z

2

Try calling Drawable.draw(Canvas) method:

@Override
public void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.save();
    canvas.setMatrix(imageMatrix);
    ((BitmapDrawable)mIcon).draw(canvas);
    canvas.restore();
}

answered Jan 18, 2012 at 7:33

a.ch.

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Comments

Ilya Gazman · Accepted Answer · 2012-01-18 06:37:47Z

-1

All you did is good, just put the super call to be the last, coz there is where all the painting is done...

@Override
public void onDraw(Canvas canvas) {
    canvas.setMatrix(imageMatrix);
    super.onDraw(canvas);
}

answered Jan 18, 2012 at 6:37

Ilya Gazman

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