CODEWITHSUNDEEP
android
Sing Kwok
Sing Kwok

Reputation: 21

Android finger rotate , zoom and move image together?

i would like to ask can the three functions rotate, zoom and move the image with user's finger happen together in one application? I found the source code to drag an image plus the zoom feature. However, i cannot find the way to add the rotation function to the code.

Can any one teach how to build these three functions together?

Upvotes: 2

Views: 3341

Answers (2)

kyogs
kyogs

Reputation: 6836

Try with below code its working for me.

float[] lastEvent = null;
float d = 0f;
float newRot = 0f;
private Matrix matrix = new Matrix();
private Matrix savedMatrix = new Matrix();
public static String fileNAME;
public static int framePos = 0;

private float scale = 0;
private float newDist = 0;

// Fields
private String TAG = this.getClass().getSimpleName();

// We can be in one of these 3 states
private static final int NONE = 0;
private static final int DRAG = 1;
private static final int ZOOM = 2;
private int mode = NONE;

// Remember some things for zooming
private PointF start = new PointF();
private PointF mid = new PointF();
float oldDist = 1f;

 public boolean onTouch(View v, MotionEvent event) {
            ImageView view = (ImageView) v;

            // Handle touch events here...
            switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                savedMatrix.set(matrix);
                start.set(event.getX(), event.getY());
                mode = DRAG;
                lastEvent = null;
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                oldDist = spacing(event);
                if (oldDist > 10f) {
                    savedMatrix.set(matrix);
                    midPoint(mid, event);
                    mode = ZOOM;
                }
                lastEvent = new float[4];
                lastEvent[0] = event.getX(0);
                lastEvent[1] = event.getX(1);
                lastEvent[2] = event.getY(0);
                lastEvent[3] = event.getY(1);
                d = rotation(event);
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_POINTER_UP:
                mode = NONE;
                lastEvent = null;
                break;
            case MotionEvent.ACTION_MOVE:
                if (mode == DRAG) {
                    // ...
                    matrix.set(savedMatrix);
                    matrix.postTranslate(event.getX() - start.x, event.getY()
                            - start.y);
                } else if (mode == ZOOM && event.getPointerCount() == 2) {
                    float newDist = spacing(event);
                    matrix.set(savedMatrix);
                    if (newDist > 10f) {
                        float scale = newDist / oldDist;
                        matrix.postScale(scale, scale, mid.x, mid.y);
                    }
                    if (lastEvent != null) {
                        newRot = rotation(event);
                        float r = newRot - d;
                        matrix.postRotate(r, view.getMeasuredWidth() / 2,
                                view.getMeasuredHeight() / 2);
                    }
                }
                break;
            }

            view.setImageMatrix(matrix);

            return true;
        }

//For rotate image on multi-touch.

private float rotation(MotionEvent event) {
    double delta_x = (event.getX(0) - event.getX(1));
    double delta_y = (event.getY(0) - event.getY(1));
    double radians = Math.atan2(delta_y, delta_x);

    return (float) Math.toDegrees(radians);
}
private float spacing(MotionEvent event) {
        float x = event.getX(0) - event.getX(1);
        float y = event.getY(0) - event.getY(1);
        return FloatMath.sqrt(x * x + y * y);
    }

private void midPoint(PointF point, MotionEvent event) {
        float x = event.getX(0) + event.getX(1);
        float y = event.getY(0) + event.getY(1);
        point.set(x / 2, y / 2);
    }

Upvotes: 2

Samuel
Samuel

Reputation: 17171

I would recommend using the android-multitouch-controller. It has worked great for me, and it offers multi-touch zoom, pan, and rotate just like you want. It's licensed under Apache v2. Be careful with the rotation. Multi-touch rotation only works well with certain devices.

NOTE: rotation is quirky on older touchscreen devices that use a Synaptics or Synaptics-like "2x1D" sensor (G1, MyTouch, Droid, Nexus One) and not a true 2D sensor like the HTC Incredible or HTC EVO 4G.

Upvotes: 1

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