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androidimageviewruntimesizescale

How may I know the size of an image that has been scaled?


I have an ImageView defined as follows in XML. It's inside a custom ViewPager.

<ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/imageView"
        android:scaleType="fitXY"/>

It is working like a charm but I need to know the actual height of the image, after it has been scaled. I am taking the values in the onMeasure method of the custom ViewPager, like this:

View child = getChildAt(0);

child.measure(widthMeasureSpec, MeasureSpec
    .makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));

int h = child.getMeasuredHeight();

The height I am getting is not the height of the image scaled, it's the original size of the image before been scaled.

Thanks.


Solution

  • You override the onMeasure function to get the image matrix and find the scale values. like so

    float[] f = new float[9];
    getImageMatrix().getValues(f);
    final float scaleX = f[Matrix.MSCALE_X];
    final float scaleY = f[Matrix.MSCALE_Y];
    
    // Get the drawable's real width and height
    final Drawable d = imageView.getDrawable();
    final int origW = d.getIntrinsicWidth();
    final int origH = d.getIntrinsicHeight();
    
    // Calculate the actual dimensions
    final int actW = Math.round(origW * scaleX);
    final int actH = Math.round(origH * scaleY);
    log.v("actual dimensions",""+actW+actH);
    

    Source :https://stackoverflow.com/a/15538856/4743812