[Android] Composited selection handle rendering

content/public/android/java/src/org/chromium/content/browser/input/HandleViewResources.java

+// Copyright 2012 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.content.browser.input;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.content.res.TypedArray;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Canvas;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+
+/**
+ * Helper class for retrieving resources related to selection handles.
+ */
+@JNINamespace("content")
+public class HandleViewResources {
+    private static final int[] LEFT_HANDLE_ATTRS = {
+        android.R.attr.textSelectHandleLeft,
+    };
+
+    private static final int[] CENTER_HANDLE_ATTRS = {
+        android.R.attr.textSelectHandle,
+    };
+
+    private static final int[] RIGHT_HANDLE_ATTRS = {
+        android.R.attr.textSelectHandleRight,
+    };
+
+    public static Drawable getLeftHandleDrawable(Context context) {
+        return getHandleDrawable(context, LEFT_HANDLE_ATTRS);
+    }
+
+    public static Drawable getCenterHandleDrawable(Context context) {
+        return getHandleDrawable(context, CENTER_HANDLE_ATTRS);
+    }
+
+    public static Drawable getRightHandleDrawable(Context context) {
+        return getHandleDrawable(context, RIGHT_HANDLE_ATTRS);
+    }
+
+    private static Drawable getHandleDrawable(Context context, final int[] attrs) {
+        TypedArray a = context.getTheme().obtainStyledAttributes(attrs);
+        Drawable drawable = a.getDrawable(0);
+        a.recycle();
+        return drawable;
+    }
+
+    private static Bitmap getHandleBitmap(Context context, final int[] attrs) {
+        // TODO(jdduke): Properly derive and apply theme color.
+        TypedArray a = context.getTheme().obtainStyledAttributes(attrs);
+        final int resId = a.getResourceId(a.getIndex(0), 0);
+        final Resources res = a.getResources();
+        a.recycle();
+
+        final Bitmap.Config config = Bitmap.Config.ARGB_8888;
+        final BitmapFactory.Options options = new BitmapFactory.Options();
+        options.inJustDecodeBounds = false;
+        options.inPreferredConfig = config;
+        final Bitmap bitmap = BitmapFactory.decodeResource(res, resId, options);
+        if (bitmap != null) return bitmap;
+
+        Drawable drawable = getHandleDrawable(context, attrs);
+        assert drawable != null;
+        if (drawable instanceof BitmapDrawable) {
+            final Bitmap drawableBitmap = ((BitmapDrawable)drawable).getBitmap();
+            if (drawableBitmap != null && drawableBitmap.getConfig() == config) {
+                return drawableBitmap;
+            }
+        }
+
+        final int width = drawable.getIntrinsicWidth();
+        final int height = drawable.getIntrinsicHeight();
+        Bitmap canvasBitmap = Bitmap.createBitmap(width, height, config);
+        Canvas canvas = new Canvas(canvasBitmap);
+        drawable.draw(canvas);
+        return canvasBitmap;
+    }
+
+    @CalledByNative
+    private static Bitmap getLeftHandleBitmap(Context context) {
+        return getHandleBitmap(context, LEFT_HANDLE_ATTRS);
+    }
+
+    @CalledByNative
+    private static Bitmap getCenterHandleBitmap(Context context) {
+        return getHandleBitmap(context, CENTER_HANDLE_ATTRS);
+    }
+
+    @CalledByNative
+    private static Bitmap getRightHandleBitmap(Context context) {
+        return getHandleBitmap(context, RIGHT_HANDLE_ATTRS);
+    }
+}