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;
}
}
本文参考链接：https://www.cnblogs.com/djw12333/p/10900182.html
