/** applies the next step in the pan-zoom animation, if any */
private void stepPanZoomAnimation() {
if (zoomPanAnimationEndTime == 0) return;
long now = System.currentTimeMillis();
if (now >= zoomPanAnimationEndTime) {
zoom = zoomTo;
drawOffset.x = panTo.x;
drawOffset.y = panTo.y;
stopPanZoomAnimation();
} else {
long duration = zoomPanAnimationEndTime - zoomPanAnimationStartTime;
long diff = zoomPanAnimationEndTime - now;
float alpha = (float) Math.pow(diff / (float) duration, zoomPanAnimationInterpolationPower);
float beta = 1.0f - alpha;
zoom = (zoomFrom * alpha) + (zoomTo * beta);
drawOffset.x = (int) ((panFrom.x * alpha) + (panTo.x * beta));
drawOffset.y = (int) ((panFrom.y * alpha) + (panTo.y * beta));
}
}
/**
* Starts a pan-zoom animation.
*
* @param toX what x coordinate to zoom to
* @param toY what y coordinate to zoom to
* @param zoomTo the new zoom factor
* @param duration_msec how long to animate
* @param zoomPanAnimationInterpolationPower 1 means a linear interpolation will be done between
* the two animation endpoints. 2 would be quadratic, etc. A higher the number causes a faster
* beginning and a slower and smoother the ending.
*/
public void startPanZoomAnimation(
int toX,
int toY,
float zoomTo,
long duration_msec,
float zoomPanAnimationInterpolationPower) {
this.zoomTo = zoomTo;
this.panTo = new Vector2i(toX, toY);
this.panFrom = drawOffset.clone();
this.zoomFrom = zoom;
this.zoomPanAnimationStartTime = System.currentTimeMillis();
this.zoomPanAnimationEndTime = System.currentTimeMillis() + duration_msec;
this.zoomPanAnimationInterpolationPower = zoomPanAnimationInterpolationPower;
}
/** set the pan in progress to the specified amount */
public void setPanInProgress(int x, int y) {
drawOffsetExtra.set(x, y);
}
/** reset the pan to the origin and zoom to 1.0 */
public void resetView() {
drawOffset.set(0, 0);
setZoom(1.0f);
}
/** pan up by the standard amount */
public void panUp() {
drawOffset.y -= getHeight() / (DEFAULT_PAN_DIVISOR * zoom);
}
/** apply the pan in progress */
public void applyPanInProgress() {
drawOffset.add(drawOffsetExtra);
drawOffsetExtra.set(0, 0);
}
/** pan down by the standard amount */
public void panDown() {
drawOffset.y += getHeight() / (DEFAULT_PAN_DIVISOR * zoom);
}
/** pan right by the standard amount */
public void panRight() {
drawOffset.x += getWidth() / (DEFAULT_PAN_DIVISOR * zoom);
}
/** pan left by the standard amount */
public void panLeft() {
drawOffset.x -= getWidth() / (DEFAULT_PAN_DIVISOR * zoom);
}
/** set the aggregate y-axis pan */
public void setPanY(int y) {
drawOffset.y = y;
}
/** set the aggregate x-axis pan */
public void setPanX(int x) {
drawOffset.x = x;
}