bVNC多点触控分析

IBCScaleGestureDetector      多点触控手势接口
    DummyScaleGestureDetector 不支持多点触控
    ScaleGestureDetector      支持多点触控

//触屏模式
//先检测缩放模式，再检测滑动模式
simulatedTouchpadInputHandler(AbstractGestureInputHandler).onScale(IBCScaleGestureDetector)
line: 470 {

        boolean consumed = true;

        // Get the current focus.
        xCurrentFocus = detector.getFocusX();
        yCurrentFocus = detector.getFocusY();

        // If we haven't started scaling yet, we check whether a swipe is being performed.
        // The arbitrary fudge factor may not be the best way to set a tolerance...
        if (!inScaling) { //缩放模式

            // Start swiping mode only after we've moved away from the initial focal point some distance.
            if (!inSwiping) {//滑动模式，移动距离超过40个像素
                if ( (yCurrentFocus < (yInitialFocus - baseSwipeDist)) ||
                     (yCurrentFocus > (yInitialFocus + baseSwipeDist)) ||
                     (xCurrentFocus < (xInitialFocus - baseSwipeDist)) ||
                     (xCurrentFocus > (xInitialFocus + baseSwipeDist)) ) {
                    inSwiping = true;
                    xPreviousFocus = xInitialFocus;
                    yPreviousFocus = yInitialFocus;
                }
            }

            // If in swiping mode, indicate a swipe at regular intervals.
            if (inSwiping) {
                twoFingerSwipeUp = false;
                twoFingerSwipeDown = false;
                twoFingerSwipeLeft = false;
                twoFingerSwipeRight = false;
                if (yCurrentFocus < (yPreviousFocus - baseSwipeDist)) {
                    twoFingerSwipeDown = true;//向下滑动
                    xPreviousFocus = xCurrentFocus;
                    yPreviousFocus = yCurrentFocus;
                } else if (yCurrentFocus > (yPreviousFocus + baseSwipeDist)) {
                    twoFingerSwipeUp = true;//向上滑动
                    xPreviousFocus = xCurrentFocus;
                    yPreviousFocus = yCurrentFocus;
                } else if (xCurrentFocus < (xPreviousFocus - baseSwipeDist)) {
                    twoFingerSwipeRight = true;//向右滑动
                    xPreviousFocus = xCurrentFocus;
                    yPreviousFocus = yCurrentFocus;
                } else if (xCurrentFocus > (xPreviousFocus + baseSwipeDist)) {
                    twoFingerSwipeLeft = true;//向左滑动
                    xPreviousFocus = xCurrentFocus;
                    yPreviousFocus = yCurrentFocus;
                } else {
                    consumed = false;
                }
                // The faster we swipe, the faster we traverse the screen, and hence, the
                // smaller the time-delta between consumed events. We take the reciprocal
                // obtain swipeSpeed. If it goes to zero, we set it to at least one.
                long elapsedTime = detector.getTimeDelta();
                if (elapsedTime < 10) elapsedTime = 10;

                swipeSpeed = baseSwipeTime/elapsedTime;
                if (swipeSpeed == 0) swipeSpeed = 1;
                if (consumed) Log.d(TAG,"Current swipe speed: " + swipeSpeed);
            }
        }

        if (!inSwiping) {

            if ( !inScaling && Math.abs(1.0 - detector.getScaleFactor()) < minScaleFactor ) {
                Log.i(TAG,"Not scaling due to small scale factor.");
                consumed = false;
            }

            if (consumed) {
                inScaling = true;
                Log.i(TAG,"Adjust scaling " + detector.getScaleFactor());
                if (canvas != null && canvas.scaling != null)
                    canvas.scaling.adjust(activity, detector.getScaleFactor(), xCurrentFocus, yCurrentFocus);
            }
        }
        return consumed;
    }
//SimulatedTouchpadInputHandler.onScale(IBCScaleGestureDetector) line: 1
//ScaleGestureDetector.onTouchEvent(MotionEvent) line: 258
SimulatedTouchpadInputHandler(AbstractGestureInputHandler).onTouchEvent(MotionEvent)
line: 460 {
        //多点触控手势
        scaleGestures.onTouchEvent(e);

    }
//SimulatedTouchpadInputHandler.onTouchEvent(MotionEvent) line: 1
RemoteCanvasActivity.onTouchEvent(MotionEvent) line: 1217 {
    try {
        //activity检测到TouchEvent
     return inputHandler.onTouchEvent(event);
    } catch (NullPointerException e) { }
    return false;
    }