Android编程之图片相关代码集锦

/** * @param 位图 * @return 转化成的字符串 */ public static String bitmapToString(Bitmap bitmap) {  // 将Bitmap转换成字符串  String string = null;  ByteArrayOutputStream bStream = new ByteArrayOutputStream();  bitmap.compress(CompressFormat.PNG, 100, bStream);  byte[] bytes = bStream.toByteArray();  string = Base64.encodeToString(bytes, Base64.DEFAULT);  return string; } 

/** * @param string 字符串 * @return 转化成的位图 */ public static Bitmap stringToBitmap(String string) {   // 将字符串转换成Bitmap类型   Bitmap bitmap = null;   try {    byte[] bitmapArray;    bitmapArray = Base64.decode(string, Base64.DEFAULT);    bitmap = BitmapFactory.decodeByteArray(bitmapArray, 0, bitmapArray.length);   } catch (Exception e) {    e.printStackTrace();   }   return bitmap; } 

/** * @param bitmap Bitmap位图图像 * @return Drawable 转换后的Drawable对象 */ public static Drawable bitmapToDrawable(Bitmap bitmap) {  if (bitmap == null)   return null;  if (160 != bitmap.getDensity()) {   bitmap.setDensity(160);  }  return new BitmapDrawable(bitmap); } 

/**  * @param context 上下文  * @param id  图片的资源ID  * @return Drawable对象  */ public static Drawable resourceToDrawable(Context context,int id) {  return null == context ? null : bitmapToDrawable(BitmapFactory.decodeResource(context.getResources(), id)); } 

/**  * @param bytes byte数组  * @return drawble对象  */ public static Drawable byteArrayToDrawable(byte[] bytes) {  return null == bytes ? null : bitmapToDrawable(BitmapFactory.decodeByteArray(bytes, 0, bytes.length)); } 

/** * Drawble对象转Bitmap对象 * @param drawable drawble对象 * @return bitmap对象 */ public static Bitmap drawableToBitmap(Drawable drawable) {   return null == drawable ? null : ((BitmapDrawable) drawable).getBitmap(); } 

/** * @param bytes byte数组 * @return bitmap对象 */ public static Bitmap byteArrayToBitmap(byte[] bytes) {   return null == bytes ? null : BitmapFactory.decodeByteArray(bytes, 0, bytes.length); } 

/** * @param bitmap 传入的bitmap * @return 去色后的图片Bitmap对象 */ public static Bitmap toGrayscale(Bitmap bitmap) {   int width,height;   height = bitmap.getHeight();   width = bitmap.getWidth();   Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);   Canvas c = new Canvas(bmpGrayscale);   Paint paint = new Paint();   ColorMatrix cm = new ColorMatrix();   cm.setSaturation(0);   ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);   paint.setColorFilter(f);   c.drawBitmap(bitmap, 0, 0, paint);   return bmpGrayscale; } 

/** * @param url   图片的路径 * @param requireSize 缩放的尺寸 * @return 缩放后的图片Bitmap对象 */ public static Bitmap getScaleImage(String url,int requireSize) {   BitmapFactory.Options o = new BitmapFactory.Options();   // 此属性表示图片不加载到内存，只是读取图片的属性，包括图片的高宽   o.inJustDecodeBounds = true;   BitmapFactory.decodeFile(url, o);   int width_tmp = o.outWidth,height_tmp = o.outHeight;   int scale = 1;   while (true) {    if (width_tmp / 2 < requireSize || height_tmp / 2 < requireSize)     break;    width_tmp /= 2;    height_tmp /= 2;    scale *= 2;   }   BitmapFactory.Options o2 = new BitmapFactory.Options();   o2.inSampleSize = scale;   Bitmap bmp = BitmapFactory.decodeFile(url, o2);   return bmp; } 

/** * @param bitmap 图片源 * @return 处理后的图片Bitmap对象 */ public static Bitmap createMirro(Bitmap bitmap) {   int width = bitmap.getWidth();   int height = bitmap.getHeight();   int shadow_height = 15;   int[] pixels = new int[width * height];   bitmap.getPixels(pixels, 0, width, 0, 0, width, height);   // shadow effect   int alpha = 0x00000000;   for (int y = 0; y < height; y++) {    for (int x = 0; x < width; x++) {     int index = y * width + x;     int r = (pixels[index] >> 16) & 0xff;     int g = (pixels[index] >> 8) & 0xff;     int b = pixels[index] & 0xff;     pixels[index] = alpha | (r << 16) | (g << 8) | b;    }    if (y >= (height - shadow_height)) {     alpha = alpha + 0x1F000000;    }   }   // invert effect   Bitmap bm = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);   for (int y = 0; y < height; y++) {    bm.setPixels(pixels, y * width, width, 0, height - y - 1, width, 1);   }   return Bitmap.createBitmap(bm, 0, 0, width, shadow_height); } 

/** * @param imagePath 图片保存路径 * @param bm 被保存的bitmap对象 */ public static void saveImgToLocal(String imagePath, Bitmap bm) {   if (bm == null || imagePath == null || "".equals(imagePath)) {    return;   }   File f = new File(imagePath);   if (f.exists()) {    return;   } else {    try {     File parentFile = f.getParentFile();     if (!parentFile.exists()) {      parentFile.mkdirs();     }     f.createNewFile();     FileOutputStream fos;     fos = new FileOutputStream(f);     bm.compress(Bitmap.CompressFormat.PNG, 100, fos);     fos.close();    } catch (FileNotFoundException e) {     f.delete();     e.printStackTrace();    } catch (IOException e) {     e.printStackTrace();     f.delete();    }   } }

/** * @param imagePath 图片在SDCard中保存的路径 * @return 返回保存的bitmap对象 */ public static Bitmap getImageFromLocal(String imagePath) {   File file = new File(imagePath);   if (file.exists()) {    Bitmap bitmap = BitmapFactory.decodeFile(imagePath);    file.setLastModified(System.currentTimeMillis());    return bitmap;   }   return null; }

/** * 对图片进行压缩，主要是为了解决控件显示过大图片占用内存造成OOM问题。 * 一般压缩后的图片大小应该和用来展示它的控件大小相近。 * @param context 上下文 * @param resId 图片资源Id * @param reqWidth 期望压缩的宽度 * @param reqHeight 期望压缩的高度 * @return 压缩后的图片 */ public static Bitmap compressBitmapFromResourse(Context context, int resId, int reqWidth, int reqHeight) {   final BitmapFactory.Options options = new BitmapFactory.Options();   /*    * 第一次解析时，inJustDecodeBounds设置为true，    * 禁止为bitmap分配内存，虽然bitmap返回值为空，但可以获取图片大小    */   options.inJustDecodeBounds = true;   BitmapFactory.decodeResource(context.getResources(), resId, options);   final int height = options.outHeight;   final int width = options.outWidth;   int inSampleSize = 1;   if (height > reqHeight || width > reqWidth) {    final int heightRatio = Math.round((float) height / (float) reqHeight);   final int widthRatio = Math.round((float) width / (float) reqWidth);   inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;  }   options.inSampleSize = inSampleSize;   //使用计算得到的inSampleSize值再次解析图片   options.inJustDecodeBounds = false;   return BitmapFactory.decodeResource(context.getResources(), resId, options); }

private int getMaxMemoryForApp() {   int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);   return maxMemory; }

/** * 将Bitmap处理为圆形的图片 * @param bitmap 处理之前的位图 * @return 处理之后的位图 */ public static Bitmap circlePic(Bitmap bitmap){   int width = bitmap.getWidth();   int height = bitmap.getHeight();   int r = width < height ? width/2:height/2;//圆的半径，取宽和高中较小的，以便于显示没有空白   Bitmap outBitmap = Bitmap.createBitmap(r*2, r*2, Bitmap.Config.ARGB_8888);//创建一个刚好2r大小的Bitmap   Canvas canvas = new Canvas(outBitmap);   final int color =0xff424242;   final Paint paint = new Paint();   /**    * 截取图像的中心的一个正方形,用于在原图中截取    * 坐标如下：    * 1.如果 w < h , 左上坐标(0, (h-w)/2) , 右上坐标(w, (h+w)/2) 偏移10    * 2.如果 w > h , 左上坐标((w-h)/2, 0) , 右上坐标((w+h)/2, h) 偏移10    */   final Rect rect = new Rect( width < height ? 0 : (width-height)/2, width < height ? (height-width)/2 - 10 : -10,     width < height ? width : (width+height)/2, (width < height ? (height+width)/2 - 10: height - 10));   //创建一个直径大小的正方形，用于设置canvas的显示与设置画布截取   final Rect rect2 = new Rect( 0, 0, r*2, r*2);   //提高精度，用于消除锯齿   final RectF rectF = new RectF(rect2);   //下面是设置画笔和canvas   paint.setAntiAlias(true);   canvas.drawARGB(0,0,0,0);   paint.setColor(color);   //设置圆角，半径都为r,大小为rect2   canvas.drawRoundRect(rectF, r, r, paint);   //设置图像重叠时的显示方式   paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));   //绘制图像到canvas   canvas.drawBitmap(bitmap, rect, rect2, paint);   return outBitmap;  } }