Android中经常会遇到对图片进行二次处理,例如加圆角,或者显示圆形图片。接下来我们再介绍一种方法。

首先,

自定义ImageView:

  android:id="@+id/iv"

  android:layout_width="300dp"

  android:layout_height="300dp"

  android:layout_centerHorizontal="true"

  />

  ImageView iv = findViewById(R.id.iv);

  Bitmap bitmap =BitmapFactory.decodeResource(getResources(), R.drawable.fengjing);

  Bitmap outBitmap =getRoundBitmapByShader(bitmap, 500,300,20, 3);

  iv.setImageBitmap(outBitmap);

  public class RoundRectImageView extends ImageView{

  private Paint paint;

  public RoundRectImageView(Context context) {

  this(context,null);

  }

  public RoundRectImageView(Context context, AttributeSet attrs) {

  this(context, attrs,0);

  }

  public RoundRectImageView(Context context, AttributeSet attrs, int defStyle) {

  super(context, attrs, defStyle);

  paint = new Paint();

  }

  /**

  * 绘制圆角矩形图片

  * @author caizhiming

  */

  @Override

  protected void onDraw(Canvas canvas) {

  Drawable drawable = getDrawable();

  if (null != drawable) {

  Bitmap bitmap = getBitmapFromDrawable(drawable);

  // Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();

  Bitmap b = getRoundBitmapByShader(bitmap,getWidth(),getHeight(), 50,0);

  final Rect rectSrc = new Rect(0, 0, b.getWidth(), b.getHeight());

  final Rect rectDest = new Rect(0,0,getWidth(),getHeight());

  paint.reset();

  canvas.drawBitmap(b, rectSrc, rectDest, paint);

  } else {

  super.onDraw(canvas);

  }

  }

  /**

  * 把资源图片转换成Bitmap

  * @param drawable

  * 资源图片

  * @return 位图

  */

  public static Bitmap getBitmapFromDrawable(Drawable drawable) {

  int width = drawable.getIntrinsicWidth();

  int height = drawable.getIntrinsicHeight();

  Bitmap bitmap = Bitmap.createBitmap(width, height, drawable

  .getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888

  : Bitmap.Config.RGB_565);

  Canvas canvas = new Canvas(bitmap);

  //drawable.setBounds(-4, -4, width + 4, height + 4);

  drawable.draw(canvas);

  return bitmap;

  }

  public static Bitmap getRoundBitmapByShader(Bitmap bitmap, int outWidth, int outHeight, int radius, int boarder) {

  if (bitmap == null) {

  return null;

  }

  int width = bitmap.getWidth();

  int height = bitmap.getHeight();

  float widthScale = outWidth * 1f / width;

  float heightScale = outHeight * 1f / height;

  Matrix matrix = new Matrix();

  matrix.setScale(widthScale, heightScale);

  //创建输出的bitmap

  Bitmap desBitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.ARGB_8888);

  //创建canvas并传入desBitmap,这样绘制的内容都会在desBitmap上

  Canvas canvas = new Canvas(desBitmap);

  Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

  //创建着色器

  BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);

  //给着色器配置matrix

  bitmapShader.setLocalMatrix(matrix);

  paint.setShader(bitmapShader);

  //创建矩形区域并且预留出border

  RectF rect = new RectF(boarder, boarder, outWidth - boarder, outHeight - boarder);

  //把传入的bitmap绘制到圆角矩形区域内

  canvas.drawRoundRect(rect, radius, radius, paint);

  if (boarder > 0) {

  //绘制boarder无锡妇科费用 http://www.wxbhnkyy39.com

  Paint boarderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

  boarderPaint.setColor(Color.GREEN);

  boarderPaint.setStyle(Paint.Style.STROKE);

  boarderPaint.setStrokeWidth(boarder);

  canvas.drawRoundRect(rect, radius, radius, boarderPaint);

  }

  return desBitmap;

  }

  }

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