ninepatch/src/com/android/ninepatch/NinePatch.java

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.ninepatch;

import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Locale;

/**
 * Represents a 9-Patch bitmap.
 *
 * DO NOT CHANGE THIS API OR OLDER VERSIONS OF LAYOUTLIB WILL CRASH.
 *
 * This is a full representation of a NinePatch with both a {@link BufferedImage} and a
 * {@link NinePatchChunk}.
 *
 * Newer versions of the Layoutlib will use only the {@link NinePatchChunk} as the default
 * nine patch drawable references a normal Android bitmap which contains a BufferedImage
 * through a Bitmap_Delegate.
 *
 */
public class NinePatch {
    public static final String EXTENSION_9PATCH = ".9.png";

    private BufferedImage mImage;
    private NinePatchChunk mChunk;

    public BufferedImage getImage() {
        return mImage;
    }

    public NinePatchChunk getChunk() {
        return mChunk;
    }

    /**
     * LEGACY METHOD to run older versions of Android Layoutlib.
     *  ==== DO NOT CHANGE ====
     *
     * Loads a 9 patch or regular bitmap.
     * @param fileUrl the URL of the file to load.
     * @param convert if <code>true</code>, non 9-patch bitmap will be converted into a 9 patch.
     * If <code>false</code> and the bitmap is not a 9 patch, the method will return
     * <code>null</code>.
     * @return a {@link NinePatch} or <code>null</code>.
     * @throws IOException
     */
    public static NinePatch load(URL fileUrl, boolean convert) throws IOException {
        BufferedImage image = null;
        try {
            image  = GraphicsUtilities.loadCompatibleImage(fileUrl);
        } catch (MalformedURLException e) {
            // really this shouldn't be happening since we're not creating the URL manually.
            return null;
        }

        boolean is9Patch = fileUrl.getPath().toLowerCase(Locale.US).endsWith(EXTENSION_9PATCH);

        return load(image, is9Patch, convert);
    }

    /**
     * LEGACY METHOD to run older versions of Android Layoutlib.
     *  ==== DO NOT CHANGE ====
     *
     * Loads a 9 patch or regular bitmap.
     * @param stream the {@link InputStream} of the file to load.
     * @param is9Patch whether the file represents a 9-patch
     * @param convert if <code>true</code>, non 9-patch bitmap will be converted into a 9 patch.
     * If <code>false</code> and the bitmap is not a 9 patch, the method will return
     * <code>null</code>.
     * @return a {@link NinePatch} or <code>null</code>.
     * @throws IOException
     */
    public static NinePatch load(InputStream stream, boolean is9Patch, boolean convert)
            throws IOException {
        BufferedImage image = null;
        try {
            image  = GraphicsUtilities.loadCompatibleImage(stream);
        } catch (MalformedURLException e) {
            // really this shouldn't be happening since we're not creating the URL manually.
            return null;
        }

        return load(image, is9Patch, convert);
    }

    /**
     * LEGACY METHOD to run older versions of Android Layoutlib.
     *  ==== DO NOT CHANGE ====
     *
     * Loads a 9 patch or regular bitmap.
     * @param image the source {@link BufferedImage}.
     * @param is9Patch whether the file represents a 9-patch
     * @param convert if <code>true</code>, non 9-patch bitmap will be converted into a 9 patch.
     * If <code>false</code> and the bitmap is not a 9 patch, the method will return
     * <code>null</code>.
     * @return a {@link NinePatch} or <code>null</code>.
     * @throws IOException
     */
    public static NinePatch load(BufferedImage image, boolean is9Patch, boolean convert) {
        if (is9Patch == false) {
            if (convert) {
                image = convertTo9Patch(image);
            } else {
                return null;
            }
        } else {
            ensure9Patch(image);
        }

        return new NinePatch(image);
    }

    /**
     * LEGACY METHOD to run older versions of Android Layoutlib.
     *  ==== DO NOT CHANGE ====
     *
     * @return
     */
    public int getWidth() {
        return mImage.getWidth();
    }

    /**
     * LEGACY METHOD to run older versions of Android Layoutlib.
     *  ==== DO NOT CHANGE ====
     *
     * @return
     */
    public int getHeight() {
        return mImage.getHeight();
    }

    /**
     * LEGACY METHOD to run older versions of Android Layoutlib.
     *  ==== DO NOT CHANGE ====
     *
     * @param padding array of left, top, right, bottom padding
     * @return
     */
    public boolean getPadding(int[] padding) {
        mChunk.getPadding(padding);
        return true;
    }


    /**
     * LEGACY METHOD to run older versions of Android Layoutlib.
     *  ==== DO NOT CHANGE ====
     *
     * @param graphics2D
     * @param x
     * @param y
     * @param scaledWidth
     * @param scaledHeight
     */
    public void draw(Graphics2D graphics2D, int x, int y, int scaledWidth, int scaledHeight) {
        mChunk.draw(mImage, graphics2D, x, y, scaledWidth, scaledHeight, 0 , 0);
    }

    private NinePatch(BufferedImage image) {
        mChunk = NinePatchChunk.create(image);
        mImage = extractBitmapContent(image);
    }

    private static void ensure9Patch(BufferedImage image) {
        int width = image.getWidth();
        int height = image.getHeight();
        for (int i = 0; i < width; i++) {
            int pixel = image.getRGB(i, 0);
            if (pixel != 0 && pixel != 0xFF000000) {
                image.setRGB(i, 0, 0);
            }
            pixel = image.getRGB(i, height - 1);
            if (pixel != 0 && pixel != 0xFF000000) {
                image.setRGB(i, height - 1, 0);
            }
        }
        for (int i = 0; i < height; i++) {
            int pixel = image.getRGB(0, i);
            if (pixel != 0 && pixel != 0xFF000000) {
                image.setRGB(0, i, 0);
            }
            pixel = image.getRGB(width - 1, i);
            if (pixel != 0 && pixel != 0xFF000000) {
                image.setRGB(width - 1, i, 0);
            }
        }
    }

    private static BufferedImage convertTo9Patch(BufferedImage image) {
        BufferedImage buffer = GraphicsUtilities.createTranslucentCompatibleImage(
                image.getWidth() + 2, image.getHeight() + 2);

        Graphics2D g2 = buffer.createGraphics();
        g2.drawImage(image, 1, 1, null);
        g2.dispose();

        return buffer;
    }

    private BufferedImage extractBitmapContent(BufferedImage image) {
        return image.getSubimage(1, 1, image.getWidth() - 2, image.getHeight() - 2);
    }

}