/** * Creates a new graphical view. * * @param view the graphical view * @param chart the chart to be drawn */ public TouchHandler(GraphicalView view, AbstractChart chart) { graphicalView = view; zoomR = graphicalView.getZoomRectangle(); if (chart instanceof XYChart) { mRenderer = ((XYChart) chart).getRenderer(); } else { mRenderer = ((RoundChart) chart).getRenderer(); } if (mRenderer.isPanEnabled()) { mPan = new Pan(chart); } if (mRenderer.isZoomEnabled()) { mPinchZoom = new Zoom(chart, true, 1); } }
/** * Handles the touch event. * * @param event the touch event */ public boolean handleTouch(MotionEvent event) { int action = event.getAction(); if (mRenderer != null && action == MotionEvent.ACTION_MOVE) { if (oldX >= 0 || oldY >= 0) { float newX = event.getX(0); float newY = event.getY(0); if (event.getPointerCount() > 1 && (oldX2 >= 0 || oldY2 >= 0) && mRenderer.isZoomEnabled()) { float newX2 = event.getX(1); float newY2 = event.getY(1); float newDeltaX = Math.abs(newX - newX2); float newDeltaY = Math.abs(newY - newY2); float oldDeltaX = Math.abs(oldX - oldX2); float oldDeltaY = Math.abs(oldY - oldY2); float zoomRate = 1; float tan1 = Math.abs(newY - oldY) / Math.abs(newX - oldX); float tan2 = Math.abs(newY2 - oldY2) / Math.abs(newX2 - oldX2); if (tan1 <= 0.25 && tan2 <= 0.25) { // horizontal pinch zoom, |deltaY| / |deltaX| is [0 ~ 0.25], 0.25 is // the approximate value of tan(PI / 12) zoomRate = newDeltaX / oldDeltaX; applyZoom(zoomRate, Zoom.ZOOM_AXIS_X); } else if (tan1 >= 3.73 && tan2 >= 3.73) { // pinch zoom vertically, |deltaY| / |deltaX| is [3.73 ~ infinity], // 3.732 is the approximate value of tan(PI / 2 - PI / 12) zoomRate = newDeltaY / oldDeltaY; applyZoom(zoomRate, Zoom.ZOOM_AXIS_Y); } else { // pinch zoom diagonally if (Math.abs(newX - oldX) >= Math.abs(newY - oldY)) { zoomRate = newDeltaX / oldDeltaX; } else { zoomRate = newDeltaY / oldDeltaY; } applyZoom(zoomRate, Zoom.ZOOM_AXIS_XY); } oldX2 = newX2; oldY2 = newY2; } else if (mRenderer.isPanEnabled()) { mPan.apply(oldX, oldY, newX, newY); oldX2 = 0; oldY2 = 0; } oldX = newX; oldY = newY; graphicalView.repaint(); return true; } } else if (action == MotionEvent.ACTION_DOWN) { oldX = event.getX(0); oldY = event.getY(0); if (mRenderer != null && mRenderer.isZoomEnabled() && zoomR.contains(oldX, oldY)) { if (oldX < zoomR.left + zoomR.width() / 3) { graphicalView.zoomIn(); } else if (oldX < zoomR.left + zoomR.width() * 2 / 3) { graphicalView.zoomOut(); } else { graphicalView.zoomReset(); } return true; } } else if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_POINTER_UP) { oldX = 0; oldY = 0; oldX2 = 0; oldY2 = 0; if (action == MotionEvent.ACTION_POINTER_UP) { oldX = -1; oldY = -1; } } return !mRenderer.isClickEnabled(); }