图片处理大全
一、相关概念
1、Drawable就是一个可画的对象，其可能是一张位图（BitmapDrawable），也可能是一个图形（ShapeDrawable），还有可能是一个图层（LayerDrawable），我们根据画图的需求，创建相应的可画对象2、Canvas画布，绘图的目的区域，用于绘图3、Bitmap位图，用于图的处理4、Matrix矩阵二、Bitmap
1、从资源中获取Bitmap
1 Resources res = getResources();2 Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.icon);
2、Bitmap → byte[]
1 public byte[] Bitmap2Bytes(Bitmap bm) {2 ByteArrayOutputStream baos = new ByteArrayOutputStream();3 bm.compress(Bitmap.CompressFormat.PNG, 100, baos);4 return baos.toByteArray();5 }
3、byte[] → Bitmap
1 public Bitmap Bytes2Bimap(byte[] b) {2 if (b.length != 0) {3 return BitmapFactory.decodeByteArray(b, 0, b.length);4 } else {5 return null;6 }7 }
4、Bitmap缩放
1 public static Bitmap zoomBitmap(Bitmap bitmap, int width, int height) { 2 int w = bitmap.getWidth(); 3 int h = bitmap.getHeight(); 4 Matrix matrix = new Matrix(); 5 float scaleWidth = ((float) width / w); 6 float scaleHeight = ((float) height / h); 7 matrix.postScale(scaleWidth, scaleHeight); 8 Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true); 9 return newbmp;10 }
5、将Drawable转化为Bitmap
1 public static Bitmap drawableToBitmap(Drawable drawable) { 2 // 取 drawable 的长宽 3 int w = drawable.getIntrinsicWidth(); 4 int h = drawable.getIntrinsicHeight(); 5 6 // 取 drawable 的颜色格式 7 Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 8 : Bitmap.Config.RGB_565; 9 // 建立对应 bitmap10 Bitmap bitmap = Bitmap.createBitmap(w, h, config);11 // 建立对应 bitmap 的画布12 Canvas canvas = new Canvas(bitmap);13 drawable.setBounds(0, 0, w, h);14 // 把 drawable 内容画到画布中15 drawable.draw(canvas);16 return bitmap;17 }
6、获得圆角图片
1 public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) { 2 int w = bitmap.getWidth(); 3 int h = bitmap.getHeight(); 4 Bitmap output = Bitmap.createBitmap(w, h, Config.ARGB_8888); 5 Canvas canvas = new Canvas(output); 6 final int color = 0xff424242; 7 final Paint paint = new Paint(); 8 final Rect rect = new Rect(0, 0, w, h); 9 final RectF rectF = new RectF(rect);10 paint.setAntiAlias(true);11 canvas.drawARGB(0, 0, 0, 0);12 paint.setColor(color);13 canvas.drawRoundRect(rectF, roundPx, roundPx, paint);14 paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));15 canvas.drawBitmap(bitmap, rect, rect, paint);16 17 return output;18 }
7、获得带倒影的图片
1 public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap) { 2 final int reflectionGap = 4; 3 int w = bitmap.getWidth(); 4 int h = bitmap.getHeight(); 5 6 Matrix matrix = new Matrix(); 7 matrix.preScale(1, -1); 8 9 Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, h / 2, w,10 h / 2, matrix, false);11 12 Bitmap bitmapWithReflection = Bitmap.createBitmap(w, (h + h / 2),13 Config.ARGB_8888);14 15 Canvas canvas = new Canvas(bitmapWithReflection);16 canvas.drawBitmap(bitmap, 0, 0, null);17 Paint deafalutPaint = new Paint();18 canvas.drawRect(0, h, w, h + reflectionGap, deafalutPaint);19 20 canvas.drawBitmap(reflectionImage, 0, h + reflectionGap, null);21 22 Paint paint = new Paint();23 LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,24 bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff,25 0x00ffffff, TileMode.CLAMP);26 paint.setShader(shader);27 // Set the Transfer mode to be porter duff and destination in28 paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));29 // Draw a rectangle using the paint with our linear gradient30 canvas.drawRect(0, h, w, bitmapWithReflection.getHeight()31 + reflectionGap, paint);32 33 return bitmapWithReflection;34 }
三、Drawable
1、Bitmap转换成Drawable
1 Bitmap bm=xxx; //xxx根据你的情况获取2 BitmapDrawable bd= new BitmapDrawable(getResource(), bm); 3 因为BtimapDrawable是Drawable的子类，最终直接使用bd对象即可。2、Drawable缩放
1 public static Drawable zoomDrawable(Drawable drawable, int w, int h) { 2 int width = drawable.getIntrinsicWidth(); 3 int height = drawable.getIntrinsicHeight(); 4 // drawable转换成bitmap 5 Bitmap oldbmp = drawableToBitmap(drawable); 6 // 创建操作图片用的Matrix对象 7 Matrix matrix = new Matrix(); 8 // 计算缩放比例 9 float sx = ((float) w / width);10 float sy = ((float) h / height);11 // 设置缩放比例12 matrix.postScale(sx, sy);13 // 建立新的bitmap，其内容是对原bitmap的缩放后的图14 Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height,15 matrix, true);16 return new BitmapDrawable(newbmp);17 }