Android设置图片圆角的方法

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

实现的效果图：

方法一：

通过第三方框架glide实现图片显示有圆角，有三种写法如下：

1.1、第一种实现：

requestoptions options = new requestoptions().error(r.drawable.img_load_failure).bitmaptransform(new roundedcorners(30));//图片圆角为30
glide.with(this).load(url) //图片地址
    .apply(options)
    .into(imagview);

1.2、第二种实现：

requestoptions requestoptions = new requestoptions();
requestoptions.placeholder(r.drawable.ic_launcher_background);
requestoptions.circlecroptransform();
requestoptions.transforms( new roundedcorners(30));
glide.with(this).load(url) //图片地址
    .apply(options)
    .into(imagview);

1.3、第三种实现：

requestoptions options = new requestoptions().centercrop() .transform(new roundtransform(this,30)); 
glide.with(this).load(url) //图片地址
    .apply(options)
    .into(imagview);

public class roundtransform extends bitmaptransformation { 
 private static float radius = 0f; 
 public roundtransform(context context) { 
  this(context, 4); 
 } 
 
 public roundtransform(context context, int dp) { 
  super(context); 
  this.radius = resources.getsystem().getdisplaymetrics().density * dp; 
 } 
 
 @override 
 protected bitmap transform(bitmappool pool, bitmap totransform, int outwidth, int outheight) { 
  bitmap bitmap = transformationutils.centercrop(pool, totransform, outwidth, outheight); 
  return roundcrop(pool, bitmap); 
 } 
 
 private static bitmap roundcrop(bitmappool pool, bitmap source) { 
  if (source == null) return null; 
  bitmap result = pool.get(source.getwidth(), source.getheight(), bitmap.config.argb_8888); 
  if (result == null) { 
   result = bitmap.createbitmap(source.getwidth(), source.getheight(), bitmap.config.argb_8888); 
  } 
 
  canvas canvas = new canvas(result); 
  paint paint = new paint(); 
  paint.setshader(new bitmapshader(source, bitmapshader.tilemode.clamp, bitmapshader.tilemode.clamp)); 
  paint.setantialias(true); 
  rectf rectf = new rectf(0f, 0f, source.getwidth(), source.getheight()); 
  canvas.drawroundrect(rectf, radius, radius, paint); 
  return result; 
 } 
 
 public string getid() { 
  return getclass().getname() + math.round(radius); 
 } 
 
 @override 
 public void updatediskcachekey(messagedigest messagedigest) { 
 
 }
}

方法二：

自定义imageview：

<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
   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;
 }
 
}

方法三：

对图片进行处理，此方法还可以加边框

/**
 * 通过bitmapshader实现圆形边框
 * @param bitmap 
 * @param outwidth 输出的图片宽度
 * @param outheight 输出的图片高度
 * @param radius 圆角大小
 * @param boarder 边框宽度
 */
public static bitmap getroundbitmapbyshader(bitmap bitmap, int outwidth, int outheight, int radius, int boarder) {
 if (bitmap == null) {
  return null;
 }
 int height = bitmap.getheight();
 int width = bitmap.getwidth();
 
 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
  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;
}

实现圆形和边框：

/**
 * 通过bitmapshader实现圆形边框
 * @param bitmap 
 * @param outwidth 输出的图片宽度
 * @param outheight 输出的图片高度
 * @param boarder 边框大小
 */
public static bitmap getcirclebitmapbyshader(bitmap bitmap, int outwidth, int outheight, int boarder) {
int radius;
int width = bitmap.getwidth();
int height = bitmap.getheight();
float widthscale = outwidth * 1f / width;
float heightscale = outheight * 1f / height;
 
bitmap desbitmap = bitmap.createbitmap(outwidth, outheight, bitmap.config.argb_8888);
if (outheight > outwidth) {
 radius = outwidth / 2;
} else {
 radius = outheight / 2;
}
//创建canvas
canvas canvas = new canvas(desbitmap);
paint paint = new paint(paint.anti_alias_flag);
bitmapshader bitmapshader = new bitmapshader(bitmap, shader.tilemode.clamp, shader.tilemode.clamp);
matrix matrix = new matrix();
matrix.setscale(widthscale, heightscale);
bitmapshader.setlocalmatrix(matrix);
paint.setshader(bitmapshader);
canvas.drawcircle(outwidth / 2, outheight / 2, radius - boarder, paint);
if (boarder > 0) {
 //绘制boarder
 paint boarderpaint = new paint(paint.anti_alias_flag);
 boarderpaint.setcolor(color.green);
 boarderpaint.setstyle(paint.style.stroke);
 boarderpaint.setstrokewidth(boarder);
 canvas.drawcircle(outwidth / 2, outheight / 2, radius - boarder, boarderpaint);
}
return desbitmap;
}

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