使用 ScaleType.CenterCrop 缩放后带有圆角的 ImageView

Question

我正在尝试裁剪图像，然后将其圆角以使其在屏幕上看起来更漂亮。

我能够做的是围绕图像的角落，但裁剪有时会切断图像的侧面（取决于图像的大小/纵横比）。

所以我想做的是进行裁剪，然后应用圆角。我该怎么做？

圆角图像：

private Bitmap getRoundedCornerBitmap(Bitmap bitmap) {
    Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);
    Canvas canvas = new Canvas(output);

    final int color = 0xff000000;
    final Paint paint = new Paint();
    final Rect rect = new Rect(0,0,bitmap.getWidth(), bitmap.getHeight());
    final RectF rectF = new RectF(rect);
    final float roundpx = 20;

    paint.setAntiAlias(true);
    canvas.drawARGB(0, 0, 0, 0);
    paint.setColor(color);
    canvas.drawRoundRect(rectF, roundpx, roundpx, paint);

    paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
    canvas.drawBitmap(bitmap, rect, rect, paint);

    return output;
}

然后我像这样设置图像视图的比例类型：imageView.setScaleType(ScaleType.CENTER_CROP)

Answer 1

如果您确实使用 ImageView ，您可以为此使用 RoundedBitmapDrawableFactory 。示例：

class MainActivity : AppCompatActivity() {

    companion object {
        @JvmStatic
        fun getCircularDrawable(context: Context, bitmap: Bitmap): RoundedBitmapDrawable {
            val size = Math.min(bitmap.width, bitmap.height)
            val centerCropBitmap = ThumbnailUtils.extractThumbnail(bitmap, size, size)
            val roundedBitmapDrawable = RoundedBitmapDrawableFactory.create(context.resources, centerCropBitmap)
            roundedBitmapDrawable.isFilterBitmap = true
            roundedBitmapDrawable.setAntiAlias(true)
            roundedBitmapDrawable.isCircular = true
            return roundedBitmapDrawable
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        imageView.setImageDrawable(getCircularDrawable(this, BitmapFactory.decodeResource(resources, R.drawable.test)))
    }
}

结果：

缺点是我找不到只提供原始位图的方法，所以我必须先对其进行中心裁剪。我已经要求拥有这种能力here。

Answer 2

如果你用 cardview 包装你的 imageview，你就实现了。

<android.support.v7.widget.CardView 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    card_view:cardCornerRadius="4dp"
    card_view:cardElevation="4dp"
    card_view:cardUseCompatPadding="true">
        <ImageView
            android:id="@+id/ivImage"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/your_image" />
</android.support.v7.widget.CardView>

Answer 3

试试这个：

public class RoundedImageView extends ImageView {

private Path mMaskPath;
private Paint mMaskPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
private int mCornerRadius = 10;

public RoundedImageView(Context context) {
    super(context);

    init();
}

public RoundedImageView(Context context, AttributeSet attributeSet) {
    super(context, attributeSet);

    init();
}

public RoundedImageView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);

    init();
}

private void init() {
    ViewCompat.setLayerType(this, ViewCompat.LAYER_TYPE_SOFTWARE, null);
    mMaskPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
}


public void setCornerRadius(int cornerRadius) {
    mCornerRadius = cornerRadius;
    generateMaskPath(getWidth(), getHeight());
    invalidate();
}

@Override
protected void onSizeChanged(int w, int h, int oldW, int oldH) {
    super.onSizeChanged(w, h, oldW, oldH);

    if (w != oldW || h != oldH) {
        generateMaskPath(w, h);
    }
}

private void generateMaskPath(int w, int h) {
    mMaskPath = new Path();
    mMaskPath.addRoundRect(new RectF(0,0,w,h), mCornerRadius, mCornerRadius, Path.Direction.CW);
    mMaskPath.setFillType(Path.FillType.INVERSE_WINDING);
}

@Override
protected void onDraw(Canvas canvas) {
    if(canvas.isOpaque()) { // If canvas is opaque, make it transparent
        canvas.saveLayerAlpha(0, 0, canvas.getWidth(), canvas.getHeight(), 255, Canvas.HAS_ALPHA_LAYER_SAVE_FLAG);
    }

    super.onDraw(canvas);

    if(mMaskPath != null) {
        canvas.drawPath(mMaskPath, mMaskPaint);
    }
}

和

<your.pack.name.RoundedImageView
            android:id="@+id/image_id"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scaleType="centerCrop" />

RoundedImageView  iconImage = (RoundedImageView )findViewById(R.id.image_id);
iconImage.setImageBitmap(bitmap);