android bitmap的 一些简单操作

/** 获取 drawable 的图片   可以循环   1.图名    2.drawable 3.包名      **/

int imgid = getResources().getIdentifier("ic_launcher", "drawable", "com.example.anywight");
text.setBackgroundResource(imgid);

/** 通过图片id获得Bitmap  **/
Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);

/** 通过 assest 获取       获得Drawable    bitmap **/
InputStream in = this.getAssets().open("ic_launcher");
Drawable da = Drawable.createFromStream(in, null);
Bitmap mm = BitmapFactory.decodeStream(in);

/** 通过 sdcard  获得   bitmap **/
Bitmap bit = BitmapFactory.decodeFile("/sdcard/android.jpg");

/** view转Bitmap **/
public static Bitmap convertViewToBitmap(View view, int bitmapWidth, int bitmapHeight){

    Bitmap bitmap = Bitmap.createBitmap(bitmapWidth, bitmapHeight, Bitmap.Config.ARGB_8888);
    view.draw(new Canvas(bitmap));
    return bitmap;
}

/** 将控件转换为bitmap **/
public static Bitmap convertViewToBitMap(View view){
    // 打开图像缓存
    view.setDrawingCacheEnabled(true);
    // 必须调用measure和layout方法才能成功保存可视组件的截图到png图像文件
    // 测量View大小
    view.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
    // 发送位置和尺寸到View及其所有的子View
    view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
    // 获得可视组件的截图
    Bitmap bitmap = view.getDrawingCache();
    return bitmap;
}

public static Bitmap getBitmapFromView(View view){
    Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(returnedBitmap);
    Drawable bgDrawable = view.getBackground();
    if (bgDrawable != null)
        bgDrawable.draw(canvas);
    else
        canvas.drawColor(Color.WHITE);
    view.draw(canvas);
    return returnedBitmap;
}

/**  获取屏幕截图的bitmap对象的代码如下  **/
public Bitmap getScreenPic(View view){

    View rootView = view.getRootView();
    rootView.setDrawingCacheEnabled(true);
    rootView.buildDrawingCache();
    // 不明白为什么这里返回一个空，有帖子说不能在oncreat方法中调用
    // 测量View大小
    rootView.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
    // 发送位置和尺寸到View及其所有的子View
    rootView.layout(0, 0, rootView.getMeasuredWidth(), rootView.getMeasuredHeight());
    // 解决措施，调用上面的measure和layout方法之后，返回值就不再为空
    // 如果想要创建的是固定长度和宽度的呢？
    Bitmap bitmap = rootView.getDrawingCache();
    rootView.destroyDrawingCache();
    return bitmap;
}

/** Drawable → Bitmap **/
public static Bitmap drawableToBitmap(Drawable drawable){

    Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565);
    Canvas canvas = new Canvas(bitmap);
    // canvas.setBitmap(bitmap);
    drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
    drawable.draw(canvas);
    return bitmap;

}

/** bitmap → drawable **/
public static Drawable bitmapToDrawable(Context context,String filename){

     Bitmap image = null;
     BitmapDrawable ddd = null;
        try {
            AssetManager am = context.getAssets();
            InputStream is = am.open(filename);
            image = BitmapFactory.decodeStream(is);
            ddd = new BitmapDrawable(context.getResources(), image);
            is.close();
        } catch (Exception e) {
        }
     return ddd;  

}

/** byte[] → Bitmap **/
public static Bitmap byteToDrawable(Context context,byte[] bb){
     Bitmap pp  = BitmapFactory.decodeByteArray(bb, 0, bb.length);
     return pp;
}

/**  Bitmap → byte[]**/
public static byte[] bitmapToByte(Bitmap bitmap){

    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
    byte[] yy = baos.toByteArray();
    return yy;
}

/**  将text  转换成  bitmap  **/
public static Bitmap createTxtImage(String txt, int txtSize) {
    Bitmap mbmpTest = Bitmap.createBitmap(txt.length() * txtSize + 4,
            txtSize + 4, Config.ARGB_8888);
    Canvas canvasTemp = new Canvas(mbmpTest);
    Paint p = new Paint();
    p.setAntiAlias(true);
    p.setColor(Color.WHITE);
    p.setTextSize(txtSize);
    canvasTemp.drawText(txt, 2, txtSize - 2, p);
    return mbmpTest;

}

/**  显示将bitmap进行缩放       **/
public Bitmap  bitmapScanel(Context context){
    //通过openRawResource获取一个inputStream对象
    InputStream inputStream = context.getResources().openRawResource(R.id.backageground);
    //通过一个InputStream创建一个BitmapDrawable对象
    BitmapDrawable drawable = new BitmapDrawable(inputStream);
    //通过BitmapDrawable对象获得Bitmap对象
    Bitmap bitmap = drawable.getBitmap();
    //利用Bitmap对象创建缩略图
    bitmap = ThumbnailUtils.extractThumbnail(bitmap, 40, 40);
    return bitmap;

 }

  /**  放大缩小图片    **/
public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){
    int width = bitmap.getWidth();
    int height = bitmap.getHeight();
    Matrix matrix = new Matrix();
    float scaleWidht = ((float)w / width);
    float scaleHeight = ((float)h / height);
    matrix.postScale(scaleWidht, scaleHeight);
    Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
    return newbmp;
}  

/** 获得圆角图片的方法  **/
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){  

    Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
            .getHeight(), Config.ARGB_8888);
    Canvas canvas = new Canvas(output);  

    final int color = 0xff424242;
    final Paint paint = new Paint();
    final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
    final RectF rectF = new RectF(rect);  

    paint.setAntiAlias(true);
    canvas.drawARGB(0, 0, 0, 0);
    paint.setColor(color);
    canvas.drawRoundRect(rectF, roundPx, roundPx, paint);  

    paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
    canvas.drawBitmap(bitmap, rect, rect, paint);  

    return output;
}  

/** 对 bitmap 进行裁剪     **/
public Bitmap  bitmapClip(Context context , int id , int x , int y){
     Bitmap map = BitmapFactory.decodeResource(context.getResources(), id);
     map = Bitmap.createBitmap(map, x, y, 120, 120);
     return map;
}

/**
 * 图片的倒影效果
 */
public static Bitmap createReflectedImage(Bitmap originalImage) {
    final int reflectionGap = 4;

    int width = originalImage.getWidth();
    int height = originalImage.getHeight();

    Matrix matrix = new Matrix();
    matrix.preScale(1, -1);

    // Create a Bitmap with the flip matrix applied to it.
    // We only want the bottom half of the image
    Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
            height / 2, width, height / 2, matrix, false);

    // Create a new bitmap with same width but taller to fit reflection
    Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
            (height + height / 2), Config.ARGB_8888);

    // Create a new Canvas with the bitmap that's big enough for
    // the image plus gap plus reflection
    Canvas canvas = new Canvas(bitmapWithReflection);
    // Draw in the original image
    canvas.drawBitmap(originalImage, 0, 0, null);
    // Draw in the gap
    Paint defaultPaint = new Paint();
    canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);
    // Draw in the reflection
    canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

    // Create a shader that is a linear gradient that covers the reflection
    Paint paint = new Paint();
    LinearGradient shader = new LinearGradient(0,
            originalImage.getHeight(), 0, bitmapWithReflection.getHeight()
                    + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
    // Set the paint to use this shader (linear gradient)
    paint.setShader(shader);
    // Set the Transfer mode to be porter duff and destination in
    paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
    // Draw a rectangle using the paint with our linear gradient
    canvas.drawRect(0, height, width, bitmapWithReflection.getHeight() + reflectionGap, paint);

    return bitmapWithReflection;
 }