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Friday, 25 December 2009

Android: How to scale an image in ImageView

To scale an image in the provided ImageView control, use this basic code:


Matrix mtrx = new Matrix;
mtrx.postScale(scalefactorX, scalefactorY);
mtrx.postTranslate(offsetX, offsetY);
pic.setImageMatrix(mtrx);
pic.setScaleType(ScaleType.MATRIX);
pic.invalidate();


This will increase the image size by scalefactorX and scalefactorY, and move the image so that the top left corner is at the location specified by offsetX and offsetY.

1 comment:

  1. IanMac11 February 2010 at 7:44 am

    Hi

    I tried this when clicking a zoom button but it had no effect whatsoever.

    Any ideas?

    Cheers,
    Ian.

    My code is almost identical:-

    ImageView bgnd = (ImageView) findViewById(R.id.imgMap);
    Matrix mtrx = new Matrix();
    mtrx.postScale(_scaling, _scaling);
    mtrx.postTranslate(_canvasXOffset, _canvasYOffset);
    bgnd.setImageMatrix(mtrx);
    bgnd.setScaleType(ScaleType.MATRIX);
    bgnd.invalidate();

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