Source code
package android.support.design.widget;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.graphics.RectF;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;
class ViewGroupUtilsHoneycomb {
private static final Matrix IDENTITY = new Matrix();
private static final ThreadLocal<Matrix> sMatrix = new ThreadLocal();
private static final ThreadLocal<RectF> sRectF = new ThreadLocal();
ViewGroupUtilsHoneycomb() {
}
public static void offsetDescendantRect(ViewGroup group, View child, Rect rect) {
Matrix m = (Matrix) sMatrix.get();
if (m == null) {
m = new Matrix();
sMatrix.set(m);
} else {
m.set(IDENTITY);
}
offsetDescendantMatrix(group, child, m);
RectF rectF = (RectF) sRectF.get();
if (rectF == null) {
rectF = new RectF();
}
rectF.set(rect);
m.mapRect(rectF);
rect.set((int) (rectF.left + 0.5f), (int) (rectF.top + 0.5f), (int) (rectF.right + 0.5f), (int) (rectF.bottom + 0.5f));
}
static void offsetDescendantMatrix(ViewParent target, View view, Matrix m) {
ViewParent parent = view.getParent();
if ((parent instanceof View) && parent != target) {
View vp = (View) parent;
offsetDescendantMatrix(target, vp, m);
m.preTranslate((float) (-vp.getScrollX()), (float) (-vp.getScrollY()));
}
m.preTranslate((float) view.getLeft(), (float) view.getTop());
if (!view.getMatrix().isIdentity()) {
m.preConcat(view.getMatrix());
}
}
}