CropImageView in Android

CropImageView in Android

public class CropImageView extends ImageView {

    private RectF cropRect;

    public CropImageView(Context context) {
        super(context);
        init();
    }

    public CropImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    private void init() {
        cropRect = new RectF();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (getDrawable() == null) {
            return;
        }
        canvas.drawBitmap(getBitmap(), null, getBounds(), null);
        Paint paint = new Paint();
        paint.setColor(Color.RED);
        paint.setStrokeWidth(5);
        paint.setStyle(Paint.Style.STROKE);
        canvas.drawRect(cropRect, paint);
    }

    private Bitmap getBitmap() {
        BitmapDrawable drawable = (BitmapDrawable) getDrawable();
        return drawable.getBitmap();
    }

    @Override
    public void setImageBitmap(Bitmap bm) {
        super.setImageBitmap(bm);
        resetCropRect();
    }

    private void resetCropRect() {
        int bitmapWidth = getBitmap().getWidth();
        int bitmapHeight = getBitmap().getHeight();
        int viewWidth = getWidth();
        int viewHeight = getHeight();

        float left = (viewWidth - bitmapWidth) / 2f;
        float top = (viewHeight - bitmapHeight) / 2f;
        float right = left + bitmapWidth;
        float bottom = top + bitmapHeight;

        cropRect.set(left, top, right, bottom);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                break;
            case MotionEvent.ACTION_MOVE:
                float dx = event.getX() - lastX;
                float dy = event.getY() - lastY;
                cropRect.offset(dx, dy);
                invalidate();
                break;
            case MotionEvent.ACTION_UP:
                break;
        }
        lastX = event.getX();
        lastY = event.getY();
        return true;
    }

    private float lastX, lastY;

    public RectF getCropRect() {
        return cropRect;
    }

}

        

This class allows the user to crop an image by dragging and resizing a rectangular selection over it. The rectangular selection is drawn in red on top of the image. You can use this class in your Android application by adding it to your layout XML file like this:

<com.example.myapp.CropImageView
    android:id="@+id/cropImageView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:scaleType="centerInside" />

        

Then, in your activity, you can get a reference to the CropImageView object and use its getCropRect() method to retrieve the coordinates of the selected rectangle.