How to calculate touched position of ImageView in ScrollView, Considering Zoom factor?

Question

I have an image that should be click-able in certain areas, say 26 areas in that Image. What's the best way to do that ?

I made an image with same size, each click-able area in Image has specific color, with white background, so when the image is clicked, I can get the Pixel color of second image in that position and realize which area is clicked.

The problem is, i need to show picture in ScrollView, and image is resized to fit the screen width. I know i can calculate the clicked offset using event.getRawY() + sv.getScrollY();, but how to calculate the zoom factor ?

Actually since both images are the same size, i need to calculate the clicked position considering zoom factor to find the precise position of that pixel in second Image.

Answer 1

i think this snipped help you.

   @Override
public boolean onTouch(View v, MotionEvent event) {
    if (v.getId() == R.id.imageView1 || v.getId() == R.id.image_scrollview) {

        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            startX = (int) event.getX();
            startY = (int) event.getY();
            break;
        case MotionEvent.ACTION_UP:
            int cordinate_Y = (int) ((event.getY() + v.getScrollY()) / diffH);
            int cordinate_X = (int) ((event.getX() + v.getScrollX()) / diffW);
            if ((Math.abs((int) event.getX() - startX) > 10)
                    || (Math.abs((int) event.getY() - startY) > 10)) {
                break;
            }

            int pixelColor = bitmap.getPixel(cordinate_X, cordinate_Y);
            if (pixelColor != -1) {
                showDetails(texts[map.get(pixelColor)],
                        images[map.get(pixelColor)],
                        titles[map.get(pixelColor)]);

            }

            break;

        }
    }

    return false;
}