Upstream ViewUtils

BUG=429254

Review URL: https://codereview.chromium.org/882853003

Cr-Commit-Position: refs/heads/master@{#313620}

chrome/android/java/src/org/chromium/chrome/browser/util/ViewUtils.java

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.util;
+
+import android.graphics.Canvas;
+import android.view.View;
+import android.view.ViewGroup;
+
+/**
+ * View-related utility methods.
+ */
+public class ViewUtils {
+    /**
+     * Invalidates a view and all of its descendants.
+     */
+    private static void recursiveInvalidate(View view) {
+        view.invalidate();
+        if (view instanceof ViewGroup) {
+            ViewGroup group = (ViewGroup) view;
+            int childCount = group.getChildCount();
+            for (int i = 0; i < childCount; i++) {
+                View child = group.getChildAt(i);
+                if (child.getVisibility() == View.VISIBLE) {
+                    recursiveInvalidate(child);
+                }
+            }
+        }
+    }
+
+    /**
+     * Captures a bitmap of a View and draws it to a Canvas.
+     */
+    public static void captureBitmap(View view, Canvas canvas) {
+        // Invalidate all the descendants of view, before calling view.draw(). Otherwise, some of
+        // the descendant views may optimize away their drawing. http://crbug.com/415251
+        recursiveInvalidate(view);
+        view.draw(canvas);
+    }
+
+    /**
+     * Return the position of {@code childView} relative to {@code rootView}.  {@code childView}
+     * must be a child of {@code rootView}.  This returns the relative layout position, which does
+     * not include translations.
+     * @param rootView    The parent of {@code childView} to calculate the position relative to.
+     * @param childView   The {@link View} to calculate the position of.
+     * @param outPosition The resulting position with the format [x, y].
+     */
+    public static void getRelativeLayoutPosition(View rootView, View childView, int[] outPosition) {
+        assert outPosition.length == 2;
+        outPosition[0] = 0;
+        outPosition[1] = 0;
+        while (childView != null && childView != rootView) {
+            outPosition[0] += childView.getLeft();
+            outPosition[1] += childView.getTop();
+            childView = (View) childView.getParent();
+        }
+    }
+
+    /**
+     * Return the position of {@code childView} relative to {@code rootView}.  {@code childView}
+     * must be a child of {@code rootView}.  This returns the relative draw position, which includes
+     * translations.
+     * @param rootView    The parent of {@code childView} to calculate the position relative to.
+     * @param childView   The {@link View} to calculate the position of.
+     * @param outPosition The resulting position with the format [x, y].
+     */
+    public static void getRelativeDrawPosition(View rootView, View childView, int[] outPosition) {
+        assert outPosition.length == 2;
+        outPosition[0] = 0;
+        outPosition[1] = 0;
+        while (childView != null && childView != rootView) {
+            outPosition[0] += childView.getX();
+            outPosition[1] += childView.getY();
+            childView = (View) childView.getParent();
+        }
+    }
+}