117

我有一个位图，我想从这个位图中裁剪一个圆形区域。圆圈外的所有像素都应该是透明的。我怎样才能做到这一点？

在此处输入图像描述

4

19 回答 19

225

经过长时间的头脑风暴，我找到了解决方案

public Bitmap getCroppedBitmap(Bitmap bitmap) {
    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.drawRoundRect(rectF, roundPx, roundPx, paint);
    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);
    //Bitmap _bmp = Bitmap.createScaledBitmap(output, 60, 60, false);
    //return _bmp;
    return output;
}
于 2012-08-23T09:56:35.920 回答
44

从矩形生成圆形

public static Bitmap getCircularBitmap(Bitmap bitmap) {
    Bitmap output;

    if (bitmap.getWidth() > bitmap.getHeight()) {
        output = Bitmap.createBitmap(bitmap.getHeight(), bitmap.getHeight(), Config.ARGB_8888);
    } else {
        output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getWidth(), 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());

    float r = 0;

    if (bitmap.getWidth() > bitmap.getHeight()) {
        r = bitmap.getHeight() / 2;
    } else {
        r = bitmap.getWidth() / 2;
    }

    paint.setAntiAlias(true);
    canvas.drawARGB(0, 0, 0, 0);
    paint.setColor(color);
    canvas.drawCircle(r, r, r, paint);
    paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
    canvas.drawBitmap(bitmap, rect, rect, paint);
    return output;
}
于 2013-03-21T00:43:00.360 回答
41

您可以使用RoundedBitmapDrawable使您的图像视图呈圆形

这是实现roundedImageview的代码：

ImageView profilePic=(ImageView)findViewById(R.id.user_image);

//get bitmap of the image
Bitmap imageBitmap=BitmapFactory.decodeResource(getResources(),  R.drawable.large_icon);
RoundedBitmapDrawable roundedBitmapDrawable=RoundedBitmapDrawableFactory.create(getResources(), imageBitmap);

//setting radius
roundedBitmapDrawable.setCornerRadius(50.0f);
roundedBitmapDrawable.setAntiAlias(true);
profilePic.setImageDrawable(roundedBitmapDrawable);
于 2015-01-22T18:43:15.223 回答
33

@Gene 对上面的答案发表了评论，建议使用clipPath作为将图像裁剪为圆形的选项。

以下是一个干净的实现：

    public static Bitmap GetBitmapClippedCircle(Bitmap bitmap) {

        final int width = bitmap.getWidth();
        final int height = bitmap.getHeight();
        final Bitmap outputBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);

        final Path path = new Path();
        path.addCircle(
                  (float)(width / 2)
                , (float)(height / 2)
                , (float) Math.min(width, (height / 2))
                , Path.Direction.CCW);

        final Canvas canvas = new Canvas(outputBitmap);
        canvas.clipPath(path);
        canvas.drawBitmap(bitmap, 0, 0, null);
        return outputBitmap;
    }

这可以添加到实用程序类中。

于 2013-03-19T01:10:34.187 回答
14

我认为此解决方案适用于任何类型的矩形，如果您希望图像变小或变大，请更改像素大小：

public static Bitmap getCircleBitmap(Bitmap bm) {

        int sice = Math.min((bm.getWidth()), (bm.getHeight()));

        Bitmap bitmap = ThumbnailUtils.extractThumbnail(bm, sice, sice);

        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(output);

        final int color = 0xffff0000;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);

        paint.setAntiAlias(true);
        paint.setDither(true);
        paint.setFilterBitmap(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawOval(rectF, paint);

        paint.setColor(Color.BLUE);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth((float) 4);
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);

        return output;
    }
于 2014-07-18T11:20:12.813 回答
11

这也可以在 xml 中轻松完成，而无需裁剪实际位图，您只需要创建一个圆形图像蒙版并放置在您的实际图像上。这是我使用的一段代码：

圈子.xml

<?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"/>

your_layout.xml（如果不需要，请忽略 "android:scaleType="fitXY""）

<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>

维度.xml

<dimen name="icon">36dp</dimen>
<dimen name="icon_mask">55dp</dimen>

在此处输入图像描述

输出图像视图：

希望，它可能对某人有用！！！:)

于 2013-08-17T10:55:21.887 回答
8

你可以使用这个代码，它会工作

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

        final int color = Color.RED;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);

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

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

        bitmap.recycle();

        return output;
    }
于 2015-10-07T12:48:59.393 回答
7

你可以使用这个代码，它会工作

public Bitmap getRoundedShape(Bitmap scaleBitmapImage) {
    int targetWidth = 110;
    int targetHeight = 110;
    Bitmap targetBitmap = Bitmap.createBitmap(targetWidth, 
            targetHeight,Bitmap.Config.ARGB_8888);

    Canvas canvas = new Canvas(targetBitmap);
    Path path = new Path();
    path.addCircle(((float) targetWidth - 1) / 2,
            ((float) targetHeight - 1) / 2,
            (Math.min(((float) targetWidth), 
                    ((float) targetHeight)) / 2),
                    Path.Direction.CCW);

    canvas.clipPath(path);
    Bitmap sourceBitmap = scaleBitmapImage;
    canvas.drawBitmap(sourceBitmap, 
            new Rect(0, 0, sourceBitmap.getWidth(),
                    sourceBitmap.getHeight()), 
                    new Rect(0, 0, targetWidth, targetHeight), new Paint(Paint.FILTER_BITMAP_FLAG));
    return targetBitmap;
}
于 2014-07-07T15:00:14.863 回答
4

我相信最简单的解决方案是为您的位图创建一个 BitmapShader，将其传递给您的绘画对象，然后简单地调用类似 canvas.drawCircle(cx, cy, radius, paint);

例如

Paint p = new Paint();
p.setShader(new BitmapShader(myBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
canvas.drawCircle(getWidth() / 2, getHeight() / 2, getHeight() / 2, p);

这是https://github.com/hdodenhof/CircleImageView也是这样做的，你可以在这里阅读源代码： https ://github.com/hdodenhof/CircleImageView/blob/master/circleimageview/src/main/java /de/hdodenhof/circleimageview/CircleImageView.java

于 2019-01-14T15:35:24.283 回答
3

bitmap.recycle()如果您不再需要它，我建议添加它，它将防止 OutOfMemory 错误。

于 2014-07-15T09:36:04.207 回答
3

这是使用扩展方法的 Kotlin 变体

/**
 * Creates new circular bitmap based on original one.
 */
fun Bitmap.getCircularBitmap(config: Bitmap.Config = Bitmap.Config.ARGB_8888): Bitmap {
    // circle configuration
    val circlePaint = Paint().apply { isAntiAlias = true }
    val circleRadius = Math.max(width, height) / 2f

    // output bitmap
    val outputBitmapPaint = Paint(circlePaint).apply { xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN) }
    val outputBounds = Rect(0, 0, width, height)
    val output = Bitmap.createBitmap(width, height, config)

    return Canvas(output).run {
        drawCircle(circleRadius, circleRadius, circleRadius, circlePaint)
        drawBitmap(this@getCircularBitmap, outputBounds, outputBounds, outputBitmapPaint)
        output
    }
}
于 2017-10-06T19:56:55.873 回答
2

对于想要矩形中心的人（我），在切割之前添加：

    public static Bitmap cropBitmapToBlock(Bitmap bitmap) {
    if (bitmap.getWidth() >= bitmap.getHeight()){
        return Bitmap.createBitmap(
                bitmap,
                bitmap.getWidth()/2 - bitmap.getHeight()/2,
                0,
                bitmap.getHeight(),
                bitmap.getHeight()
        );
    }else{
        return Bitmap.createBitmap(
                bitmap,
                0,
                bitmap.getHeight()/2 - bitmap.getWidth()/2,
                bitmap.getWidth(),
                bitmap.getWidth()
        );
    }
}

Android 位图裁剪中心

于 2015-06-07T15:12:49.403 回答
2

基于 [Jachumbelechao Unto Mantekilla] 的回答，对于寻找 Kotlin 解决方案的人来说，这段代码就像一个魅力：

fun cropCircleFromBitmap(originalBitmap: Bitmap): Bitmap {
    val size = Math.min(originalBitmap.width, originalBitmap.height)
    val bitmap = ThumbnailUtils.extractThumbnail(originalBitmap, size, size)
    var output = Bitmap.createBitmap(bitmap.width, bitmap.height, Bitmap.Config.ARGB_8888)
    val canvas = Canvas(output)
    val paint = Paint()
    val rect = Rect(0, 0, bitmap.width, bitmap.height)
    val rectF = RectF(rect)
    paint.isAntiAlias = true
    paint.isDither = true
    paint.isFilterBitmap = true
    canvas.drawARGB(0, 0, 0, 0)
    paint.color = 0xffff0000.toInt()
    canvas.drawOval(rectF, paint)
    paint.color = Color.BLUE
    paint.style = Paint.Style.STROKE
    paint.strokeWidth = 4f
    paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN);
    canvas.drawBitmap(bitmap, rect, rect, paint)
    return output
}
于 2016-05-26T16:31:57.097 回答
1

现在，正确答案：

private Bitmap getCroppedBitmap(Bitmap bitmap, Integer cx, Integer cy, Integer radius) {
    int diam = radius << 1;
    Bitmap targetBitmap = Bitmap.createBitmap(diam, diam, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(targetBitmap);
    final int color = 0xff424242;
    final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    canvas.drawARGB(0, 0, 0, 0);
    paint.setColor(color);
    canvas.drawCircle(radius, radius, radius, paint);
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    canvas.drawBitmap(bitmap, -cx+radius, -cy+radius, paint);
    return targetBitmap;
}
于 2017-04-24T16:51:23.437 回答
1

Kotin函数

 fun getRoundedCornerBitmap(bitmap: Bitmap, pixels: Int): Bitmap {
            val output = Bitmap.createBitmap(bitmap.width, bitmap.height, Bitmap.Config.ARGB_8888)
            val canvas = Canvas(output)

            val color = -0xbdbdbe
            val paint = Paint()
            val rect = Rect(0, 0, bitmap.width, bitmap.height)
            val rectF = RectF(rect)
            val roundPx = pixels.toFloat()

            paint.isAntiAlias = true
            canvas.drawARGB(0, 0, 0, 0)
            paint.color = color
            canvas.drawRoundRect(rectF, roundPx, roundPx, paint)

            paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN)
            canvas.drawBitmap(bitmap, rect, rect, paint)

            return output
        }

通过此代码调用它

 holder.itemFriendImage.setImageBitmap(ImageConverter.getRoundedCornerBitmap(bitmap,600))
于 2017-12-16T19:40:35.677 回答
0 
**Jst Add this to your image Id and get the circuler image.**

 imgUserProfile.setImageBitmap(getCircularCenterCropBitmap(bitmap, (int) (150 * denisty)));

Method:-

public void Bitmap getCircularCenterCropBitmap(Bitmap originalBmp, int diameter) {
        Bitmap resizedBmp = BitmapUtils.getScaledCroppedBitmap(originalBmp, diameter, diameter);
        return BitmapUtils.getRoundedCircularBitmap(resizedBmp, diameter / 2);
    }
于 2018-12-24T11:18:44.763 回答
0

对于科特林：

private fun getCircularBitmap(bitmap: Bitmap): Bitmap? {
        val output = Bitmap.createBitmap(
            bitmap.width,
            bitmap.height, Bitmap.Config.ARGB_8888
        )
        val canvas = Canvas(output)
        val color = -0xbdbdbe
        val paint = Paint()
        val rect = Rect(0, 0, bitmap.width, bitmap.height)
        paint.isAntiAlias = true
        canvas.drawARGB(0, 0, 0, 0)
        paint.color = color
        canvas.drawCircle(
            (bitmap.width / 2).toFloat(), (bitmap.height / 2).toFloat(), (
                    bitmap.width / 2).toFloat(), paint
        )
        paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN)
        canvas.drawBitmap(bitmap, rect, rect, paint)
        return output
    }
于 2021-10-11T04:53:04.530 回答
0

kotlin，放到Ext.kt

 private fun Bitmap.getCircledBitmap(): Bitmap {
    val output = Bitmap.createBitmap(this.width, this.height, Bitmap.Config.ARGB_8888)
    val canvas = Canvas(output)
    val paint = Paint()
    val rect = Rect(0, 0, this.width, this.height)
    paint.isAntiAlias = true
    canvas.drawARGB(0, 0, 0, 0)
    canvas.drawCircle(this.width / 2f, this.height / 2f, this.width / 2f, paint)
    paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN)
    canvas.drawBitmap(this, rect, rect, paint)
    return output
}
于 2021-11-29T03:49:16.643 回答
-1

不确定这是一个编程问题，但......

最简单的解决方案是使源位图中的外部区域透明。否则，您必须计算哪些像素在圆外，并相应地设置 alpha（alpha = 0 表示完全透明）。

于 2012-08-13T19:16:06.337 回答