@Override
public boolean onTouchEvent(MotionEvent event) {
// Avoid short-circuit logic evaluation - ensure all gesture detectors see all events so
// that they generate correct notifications.
boolean handled = mScroller.onTouchEvent(event);
handled |= mZoomer.onTouchEvent(event);
handled |= mTapDetector.onTouchEvent(event);
mSwipePinchDetector.onTouchEvent(event);
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
mViewer.setAnimationEnabled(false);
mSuppressCursorMovement = false;
mSuppressFling = false;
mSwipeCompleted = false;
break;
case MotionEvent.ACTION_POINTER_DOWN:
mTotalMotionY = 0;
break;
case MotionEvent.ACTION_UP:
releaseAnyHeldButton();
break;
default:
break;
}
return handled;
}
/** Processes a (multi-finger) swipe gesture. */
private boolean onSwipe() {
if (mTotalMotionY > mSwipeThreshold) {
// Swipe down occurred.
mViewer.showActionBar();
} else if (mTotalMotionY < -mSwipeThreshold) {
// Swipe up occurred.
mViewer.showKeyboard();
} else {
return false;
}
mSuppressCursorMovement = true;
mSuppressFling = true;
mSwipeCompleted = true;
return true;
}
/** Moves the mouse-cursor, injects a mouse-move event and repositions the image. */
private void moveCursor(float newX, float newY) {
synchronized (mRenderData) {
// Constrain cursor to the image area.
if (newX < 0) newX = 0;
if (newY < 0) newY = 0;
if (newX > mRenderData.imageWidth) newX = mRenderData.imageWidth;
if (newY > mRenderData.imageHeight) newY = mRenderData.imageHeight;
mCursorPosition.set(newX, newY);
repositionImage();
}
mViewer.injectMouseEvent((int) newX, (int) newY, BUTTON_UNDEFINED, false);
}
/**
* Repositions the image by translating it (without affecting the zoom level) to place the cursor
* close to the center of the screen.
*/
private void repositionImage() {
synchronized (mRenderData) {
// Get the current cursor position in screen coordinates.
float[] cursorScreen = {mCursorPosition.x, mCursorPosition.y};
mRenderData.transform.mapPoints(cursorScreen);
// Translate so the cursor is displayed in the middle of the screen.
mRenderData.transform.postTranslate(
(float) mRenderData.screenWidth / 2 - cursorScreen[0],
(float) mRenderData.screenHeight / 2 - cursorScreen[1]);
// Now the cursor is displayed in the middle of the screen, see if the image can be
// panned so that more of it is visible. The primary goal is to show as much of the
// image as possible. The secondary goal is to keep the cursor in the middle.
// Get the coordinates of the desktop rectangle (top-left/bottom-right corners) in
// screen coordinates. Order is: left, top, right, bottom.
float[] rectScreen = {0, 0, mRenderData.imageWidth, mRenderData.imageHeight};
mRenderData.transform.mapPoints(rectScreen);
float leftDelta = rectScreen[0];
float rightDelta = rectScreen[2] - mRenderData.screenWidth;
float topDelta = rectScreen[1];
float bottomDelta = rectScreen[3] - mRenderData.screenHeight;
float xAdjust = 0;
float yAdjust = 0;
if (rectScreen[2] - rectScreen[0] < mRenderData.screenWidth) {
// Image is narrower than the screen, so center it.
xAdjust = -(rightDelta + leftDelta) / 2;
} else if (leftDelta > 0 && rightDelta > 0) {
// Panning the image left will show more of it.
xAdjust = -Math.min(leftDelta, rightDelta);
} else if (leftDelta < 0 && rightDelta < 0) {
// Pan the image right.
xAdjust = Math.min(-leftDelta, -rightDelta);
}
// Apply similar logic for yAdjust.
if (rectScreen[3] - rectScreen[1] < mRenderData.screenHeight) {
yAdjust = -(bottomDelta + topDelta) / 2;
} else if (topDelta > 0 && bottomDelta > 0) {
yAdjust = -Math.min(topDelta, bottomDelta);
} else if (topDelta < 0 && bottomDelta < 0) {
yAdjust = Math.min(-topDelta, -bottomDelta);
}
mRenderData.transform.postTranslate(xAdjust, yAdjust);
}
mViewer.transformationChanged();
}
@Override
public void processAnimation() {
int previousX = mFlingScroller.getCurrX();
int previousY = mFlingScroller.getCurrY();
if (!mFlingScroller.computeScrollOffset()) {
mViewer.setAnimationEnabled(false);
return;
}
int deltaX = mFlingScroller.getCurrX() - previousX;
int deltaY = mFlingScroller.getCurrY() - previousY;
float[] delta = {deltaX, deltaY};
synchronized (mRenderData) {
Matrix canvasToImage = new Matrix();
mRenderData.transform.invert(canvasToImage);
canvasToImage.mapVectors(delta);
}
moveCursor(mCursorPosition.x + delta[0], mCursorPosition.y + delta[1]);
}
/** Injects a button event using the current cursor location. */
private void injectButtonEvent(int button, boolean pressed) {
mViewer.injectMouseEvent((int) mCursorPosition.x, (int) mCursorPosition.y, button, pressed);
}