/**
* Zoom to a specified rect IN CSS PIXELS.
*
* <p>While we usually use device pixels, @zoomToRect must be specified in CSS pixels.
*/
private boolean animatedZoomTo(RectF zoomToRect) {
setState(PanZoomState.ANIMATED_ZOOM);
final float startZoom = getMetrics().zoomFactor;
RectF viewport = getMetrics().getViewport();
// 1. adjust the aspect ratio of zoomToRect to match that of the current viewport,
// enlarging as necessary (if it gets too big, it will get shrunk in the next step).
// while enlarging make sure we enlarge equally on both sides to keep the target rect
// centered.
float targetRatio = viewport.width() / viewport.height();
float rectRatio = zoomToRect.width() / zoomToRect.height();
if (FloatUtils.fuzzyEquals(targetRatio, rectRatio)) {
// all good, do nothing
} else if (targetRatio < rectRatio) {
// need to increase zoomToRect height
float newHeight = zoomToRect.width() / targetRatio;
zoomToRect.top -= (newHeight - zoomToRect.height()) / 2;
zoomToRect.bottom = zoomToRect.top + newHeight;
} else { // targetRatio > rectRatio) {
// need to increase zoomToRect width
float newWidth = targetRatio * zoomToRect.height();
zoomToRect.left -= (newWidth - zoomToRect.width()) / 2;
zoomToRect.right = zoomToRect.left + newWidth;
}
float finalZoom = viewport.width() / zoomToRect.width();
ImmutableViewportMetrics finalMetrics = getMetrics();
finalMetrics =
finalMetrics.setViewportOrigin(
zoomToRect.left * finalMetrics.zoomFactor, zoomToRect.top * finalMetrics.zoomFactor);
finalMetrics = finalMetrics.scaleTo(finalZoom, new PointF(0.0f, 0.0f));
// 2. now run getValidViewportMetrics on it, so that the target viewport is
// clamped down to prevent overscroll, over-zoom, and other bad conditions.
finalMetrics = getValidViewportMetrics(finalMetrics);
bounce(finalMetrics);
return true;
}
