将方形图像裁剪成圆形 – 以编程方式

我正在寻找过去的一天,我没有成功。

我从API获取图像,并使用以下代码将其下载到位图文件中。

private Bitmap DownloadImage(String URL) { Bitmap bitmap = null; InputStream in = null; try { in = OpenHttpConnection(URL); bitmap = BitmapFactory.decodeStream(in); in.close(); } catch (IOException e1) { e1.printStackTrace(); } return bitmap; } private InputStream OpenHttpConnection(String urlString) throws IOException { InputStream in = null; int response = -1; URL url = new URL(urlString); URLConnection conn = url.openConnection(); if (!(conn instanceof HttpURLConnection)) throw new IOException("Not an HTTP connection"); try { HttpURLConnection httpConn = (HttpURLConnection) conn; httpConn.setAllowUserInteraction(false); httpConn.setInstanceFollowRedirects(true); httpConn.setRequestMethod("GET"); httpConn.connect(); response = httpConn.getResponseCode(); if (response == HttpURLConnection.HTTP_OK) { in = httpConn.getInputStream(); } } catch (Exception ex) { throw new IOException("Error connecting"); } return in; } 

而我得到的图像作为一个正方形,我想裁剪四个angular落,使其成为圆形图像。 有没有可能的办法来实现?

欢迎任何相关的答案。 提前致谢 。

Solutions Collecting From Web of "将方形图像裁剪成圆形 – 以编程方式"

 public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); DrawingView dv = new DrawingView(this); setContentView(dv); } class DrawingView extends View { Bitmap bitmap; public DrawingView(Context context) { super(context); bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.glossy_overlay); } @Override public void onDraw(Canvas canvas) { Paint paint = new Paint(); // paint.setColor(Color.CYAN); canvas.drawBitmap(getclip(), 30, 20, paint); } public Bitmap getclip() { Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff424242; final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); // paint.setColor(color); canvas.drawCircle(bitmap.getWidth() / 2, bitmap.getHeight() / 2, bitmap.getWidth() / 2, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); canvas.drawBitmap(bitmap, rect, rect, paint); return output; } } } 

一旦检索RoundedBitmapDrawableFactory图,就可以使用RoundedBitmapDrawable从v4 Support Library生成RoundedBitmapDrawable 。 那Drawable可以被应用到一个ImageView或者直接绘制到一个Canvas

 // Create the RoundedBitmapDrawable. RoundedBitmapDrawable roundDrawable = RoundedBitmapDrawableFactory.create(getResources(), bitmap); roundDrawable.setCircular(true); // Apply it to an ImageView. ImageView imageView = (ImageView)findViewById(R.id.imageView); imageView.setImageDrawable(roundDrawable); // Alternatively, draw it to an canvas (eg in onDraw where a Canvas is available). // setBounds since there's no View handling size and positioning. roundDrawable.setBounds(left, top, right, bottom); roundDrawable.draw(canvas); 

使用function打击在位图上绘制圆,然后将带圆圈的位图设置为imageview

 public static Bitmap getclip(Bitmap bitmap) { Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888); Canvas canvas = new Canvas(output); final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); canvas.drawCircle(bitmap.getWidth() / 2, bitmap.getHeight() / 2, bitmap.getWidth() / 2, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); canvas.drawBitmap(bitmap, rect, rect, paint); return output; } 

Roman Nurik提出了一个非常直接的着色器来做这样的事情,用一个自定义drawable。

我改变了一下代码来做一个椭圆形的图像,并testing自己。 效果和performance非常好:

 public class StreamDrawable extends Drawable { private static final boolean USE_VIGNETTE = true; private final RectF mRect = new RectF(); private final BitmapShader mBitmapShader; private final Paint mPaint; private final int mMargin; public StreamDrawable(Bitmap bitmap, int margin) { mBitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP); mPaint = new Paint(); mPaint.setAntiAlias(true); mPaint.setShader(mBitmapShader); mMargin = margin; } @Override protected void onBoundsChange(Rect bounds) { super.onBoundsChange(bounds); mRect.set(mMargin, mMargin, bounds.width() - mMargin, bounds.height() - mMargin); if (USE_VIGNETTE) { RadialGradient vignette = new RadialGradient( mRect.centerX(), mRect.centerY() * 1.0f / 0.7f, mRect.centerX() * 1.3f, new int[] { 0, 0, 0x7f000000 }, new float[] { 0.0f, 0.7f, 1.0f }, Shader.TileMode.CLAMP); Matrix oval = new Matrix(); oval.setScale(1.0f, 0.7f); vignette.setLocalMatrix(oval); mPaint.setShader( new ComposeShader(mBitmapShader, vignette, PorterDuff.Mode.SRC_OVER)); } } @Override public void draw(Canvas canvas) { canvas.drawOval(mRect, mPaint); } @Override public int getOpacity() { return PixelFormat.TRANSLUCENT; } @Override public void setAlpha(int alpha) { mPaint.setAlpha(alpha); } @Override public void setColorFilter(ColorFilter cf) { mPaint.setColorFilter(cf); } } 

这可以简单地在XML中完成,请参阅我的答案在这里: https : //stackoverflow.com/a/18287979/665930

 <RelativeLayout android:id="@+id/icon_layout" android:layout_width="@dimen/icon_mask" android:layout_height="@dimen/icon_mask" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" > <ImageView android:id="@+id/icon" android:layout_width="@dimen/icon" android:layout_height="@dimen/icon" android:layout_centerInParent="true" android:scaleType="fitXY" > </ImageView> <ImageView android:id="@+id/icon_mask" android:layout_width="@dimen/icon_mask" android:layout_height="@dimen/icon_mask" android:layout_centerInParent="true" android:background="@drawable/circle" android:scaleType="fitXY" > </ImageView> </RelativeLayout> <?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" > <gradient android:startColor="#00FFFFFF" android:endColor="#00FFFFFF" android:angle="270"/> <stroke android:width="10dp" android:color="#FFAAAAAA"/>