安卓開發中Bitmap源碼實例

 安卓開發中Bitmap源碼實例

　　package android.graphics;

　　import java.awt.image.BufferedImage;

　　import java.io.File;

　　import java.io.IOException;

　　import java.io.InputStream;

　　import javax.imageio.ImageIO;

　　public final class Bitmap extends _Original_Bitmap {

　　private BufferedImage mImage;

　　public Bitmap(File input) throws IOException {

　　super(1, true, null, -1);

　　mImage = ImageIO.read(input);

　　}

　　public Bitmap(InputStream is) throws IOException {

　　super(1, true, null, -1);

　　mImage = ImageIO.read(is);

　　}

　　Bitmap(BufferedImage image) {

　　super(1, true, null, -1);

　　mImage = image;

　　}

　　public BufferedImage getImage() {

　　return mImage;

　　}

　　// ----- overriden methods

　　public enum Config {

　　// these native values must match up with the enum in SkBitmap.h

　　ALPHA_8 (2),

　　RGB_565 (4),

　　ARGB_4444 (5),

　　ARGB_8888 (6);

　　Config(int ni) {

　　this.nativeInt = ni;

　　}

　　final int nativeInt;

　　/* package */ static Config nativeToConfig(int ni) {

　　return sConfigs[ni];

　　}

　　private static Config sConfigs[] = {

　　null, null, ALPHA_8, null, RGB_565, ARGB_4444, ARGB_8888

　　};

　　}

　　@Override

　　public int getWidth() {

　　return mImage.getWidth();

　　}

　　@Override

　　public int getHeight() {

　　return mImage.getHeight();

　　}

　　/**

　　* Returns an immutable bitmap from the source bitmap. The new bitmap may

　　* be the same object as source, or a copy may have been made.

　　*/

　　public static Bitmap createBitmap(Bitmap src) {

　　return createBitmap(src, 0, 0, src.getWidth(), src.getHeight(), null, false);

　　}

　　/**

　　* Returns an immutable bitmap from the specified subset of the source

　　* bitmap. The new bitmap may be the same object as source, or a copy may

　　* have been made.

　　*

　　* @param source The bitmap we are subsetting

　　* @param x The x coordinate of the first pixel in source

　　* @param y The y coordinate of the first pixel in source

　　* @param width The number of pixels in each row

　　* @param height The number of rows

　　*/

　　public static Bitmap createBitmap(Bitmap source, int x, int y,

　　int width, int height) {

　　return new Bitmap(source.mImage.getSubimage(x, y, width, height));

　　}

　　/**

　　* Returns an immutable bitmap from subset of the source bitmap,

　　* transformed by the optional matrix.

　　*

　　* @param source The bitmap we are subsetting

　　* @param x The x coordinate of the first pixel in source

　　* @param y The y coordinate of the first pixel in source

　　* @param width The number of pixels in each row

　　* @param height The number of rows

　　* @param m Option matrix to be applied to the pixels

　　* @param filter true if the source should be filtered.

　　* Only applies if the matrix contains more than just

　　* translation.

　　* @return A bitmap that represents the specified subset of source

　　* @throws IllegalArgumentException if the x, y, width, height values are

　　* outside of the dimensions of the source bitmap.

　　*/

　　public static Bitmap createBitmap(Bitmap source, int x, int y, int width,

　　int height, Matrix m, boolean filter) {

　　checkXYSign(x, y);

　　checkWidthHeight(width, height);

　　if (x + width > source.getWidth()) {

　　throw new IllegalArgumentException(

　　"x + width must be <= bitmap.width()");

　　}

　　if (y + height > source.getHeight()) {

　　throw new IllegalArgumentException(

　　"y + height must be <= bitmap.height()");

　　}

　　// check if we can just return our argument unchanged

　　if (!source.isMutable() && x == 0 && y == 0

　　&& width == source.getWidth() && height == source.getHeight()

　　&& (m == null || m.isIdentity())) {

　　return source;

　　}

　　if (m == null || m.isIdentity()) {

　　return new Bitmap(source.mImage.getSubimage(x, y, width, height));

　　}

　　int neww = width;

　　int newh = height;

　　Paint paint;

　　Rect srcR = new Rect(x, y, x + width, y + height);

　　RectF dstR = new RectF(0, 0, width, height);

　　/* the dst should have alpha if the src does, or if our matrix

　　doesn't preserve rectness

　　*/

　　boolean hasAlpha = source.hasAlpha() || !m.rectStaysRect();

　　RectF deviceR = new RectF();

　　m.mapRect(deviceR, dstR);

　　neww = Math.round(deviceR.width());

　　newh = Math.round(deviceR.height());

　　Canvas canvas = new Canvas(neww, newh);

　　canvas.translate(-deviceR.left, -deviceR.top);

　　canvas.concat(m);

　　paint = new Paint();

　　paint.setFilterBitmap(filter);

　　if (!m.rectStaysRect()) {

　　paint.setAntiAlias(true);

　　}

　　canvas.drawBitmap(source, srcR, dstR, paint);

　　return new Bitmap(canvas.getImage());

　　}

　　/**

　　* Returns a mutable bitmap with the specified width and height.

　　*

　　* @param width The width of the bitmap

　　* @param height The height of the bitmap

　　* @param config The bitmap config to create.

　　* @throws IllegalArgumentException if the width or height are <= 0

　　*/

　　public static Bitmap createBitmap(int width, int height, Config config) {

　　return new Bitmap(new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB));

　　}

　　/**

　　* Returns a immutable bitmap with the specified width and height, with each

　　* pixel value set to the corresponding value in the colors array.

　　*

　　* @param colors Array of {@link Color} used to initialize the pixels.

　　* @param offset Number of values to skip before the first color in the

　　* array of colors.

　　* @param stride Number of colors in the array between rows (must be >=

　　* width or <= -width).

　　* @param width The width of the bitmap

　　* @param height The height of the bitmap

　　* @param config The bitmap config to create. If the config does not

　　* support per-pixel alpha (e.g. RGB_565), then the alpha

　　* bytes in the colors[] will be ignored (assumed to be FF)

　　* @throws IllegalArgumentException if the width or height are <= 0, or if

　　* the color array's length is less than the number of pixels.

　　*/

　　public static Bitmap createBitmap(int colors[], int offset, int stride,

　　int width, int height, Config config) {

　　checkWidthHeight(width, height);

　　if (Math.abs(stride) < width) {

　　throw new IllegalArgumentException("abs(stride) must be >= width");

　　}

　　int lastScanline = offset + (height - 1) * stride;

　　int length = colors.length;

　　if (offset < 0 || (offset + width > length)

　　|| lastScanline < 0

　　|| (lastScanline + width > length)) {

　　thr