Upstream ResourceManager

ui/android/java/src/org/chromium/ui/resources/statics/NinePatchData.java

+// Copyright 2014 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.ui.resources.statics;
+
+import android.graphics.Bitmap;
+import android.graphics.NinePatch;
+import android.graphics.Rect;
+
+import java.nio.BufferUnderflowException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+/**
+ * A helper class to decode and expose relevant 9-patch data from a Bitmap.
+ */
+class NinePatchData {
+    private final int mWidth;
+    private final int mHeight;
+    private final Rect mPadding;
+    private final int[] mDivX;
+    private final int[] mDivY;
+
+    private Rect mAperture;
+
+    /**
+     * Creates a {@link NinePatchData} that stores 9-patch metadata.
+     * @param width   The width of the underlying bitmap.
+     * @param height  The height of the underlying bitmap.
+     * @param padding The padding of the 9-patch for the content area.  This padding is a set of
+     *                insets (left = left padding, top = top padding, right = right padding,
+     *                bottom = bottom padding).
+     * @param divX    A run-length encoded list of stretch regions along the x dimension.  The
+     *                regions will go from 0 -> divX[0] - 1, divX[0] -> divX[1] - 1, etc..
+     * @param divY    A run-length encoded list of stretch regions along the y dimension.  The
+     *                regions will go from 0 -> divY[0] - 1, divY[0] -> divY[1] - 1, etc..
+     */
+    private NinePatchData(int width, int height, Rect padding, int[] divX, int[] divY) {
+        mWidth = width;
+        mHeight = height;
+        mPadding = new Rect(
+                padding.left, padding.top, mWidth - padding.right, mHeight - padding.bottom);
+
+        mDivX = new int[divX.length];
+        mDivY = new int[divY.length];
+
+        System.arraycopy(divX, 0, mDivX, 0, divX.length);
+        System.arraycopy(divY, 0, mDivY, 0, divY.length);
+
+        mAperture = new Rect(mDivX[0], mDivY[0], mDivX[1], mDivY[1]);
+    }
+
+    /**
+     * @return The padded content area of this 9-patch.
+     */
+    public Rect getPadding() {
+        return mPadding;
+    }
+
+    /**
+     * This class only exposes one 9-patch stretch region.
+     * @return The aperture of this 9-patch.  This specifies the center of the 9-patch, with the
+     *         surrounding areas being stretchable.
+     */
+    public Rect getAperture() {
+        return mAperture;
+    }
+
+    /**
+     * Attempts to decode 9-patch data from a {@link Bitmap}.
+     * @param bitmap The {@link Bitmap} to check.
+     * @return       An instance of {@link NinePatchData} representing the 9-patch information
+     *               encoded in {@code bitmap} or {@code null} if the {@link Bitmap} wasn't a
+     *               9-patch.
+     */
+    public static NinePatchData create(Bitmap bitmap) {
+        if (bitmap == null) return null;
+
+        try {
+            byte[] chunk = bitmap.getNinePatchChunk();
+            if (chunk == null || !NinePatch.isNinePatchChunk(chunk)) return null;
+
+            ByteBuffer buffer = ByteBuffer.wrap(chunk).order(ByteOrder.nativeOrder());
+
+            // int8_t wasDeserialized
+            if (buffer.get() == 0) return null;
+
+            // int8_t numXDivs
+            int numDivX = buffer.get();
+            if (numDivX == 0 || (numDivX & 0x01) != 0) return null;
+
+            // int8_t numYDivs
+            int numDivY = buffer.get();
+            if (numDivY == 0 || (numDivY & 0x01) != 0) return null;
+
+            // int8_t numColors
+            buffer.get();
+
+            // uint32_t xDivsOffset
+            buffer.getInt();
+
+            // uint32_t yDivsOffset
+            buffer.getInt();
+
+            Rect padding = new Rect();
+
+            // uint32_t paddingLeft
+            padding.left = buffer.getInt();
+
+            // uint32_t paddingRight
+            padding.right = buffer.getInt();
+
+            // uint32_t paddingTop
+            padding.top = buffer.getInt();
+
+            // uint32_t paddingBottom
+            padding.bottom = buffer.getInt();
+
+            // uint32_t colorsOffset
+            buffer.getInt();
+
+            // uint32_t uint32_t uint32_t ...
+            int[] divX = new int[numDivX];
+            for (int i = 0; i < numDivX; i++) divX[i] = buffer.getInt();
+
+            // uint32_t uint32_t uint32_t ...
+            int[] divY = new int[numDivY];
+            for (int i = 0; i < numDivY; i++) divY[i] = buffer.getInt();
+
+            return new NinePatchData(bitmap.getWidth(), bitmap.getHeight(), padding, divX, divY);
+        } catch (BufferUnderflowException ex) {
+            return null;
+        }
+    }
+}