Glide4 绘制圆形描边

Glide使用CircleCrop即可加载圆形图片，有时需求需要给图片加上一层白色描边：

复制一份TransformationUtils，修改circleCrop()方法，

// 描边画笔。
private static final Paint CIRCLE_CROP_WHITE_PAINT;
private static final int STROKE_WIDTH = 3;

static {
    // 这是Glide源码。
    CIRCLE_CROP_BITMAP_PAINT = new Paint(CIRCLE_CROP_PAINT_FLAGS);
    CIRCLE_CROP_BITMAP_PAINT.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    // 描边画笔初始化。
    CIRCLE_CROP_WHITE_PAINT = new Paint(CIRCLE_CROP_PAINT_FLAGS);
    CIRCLE_CROP_WHITE_PAINT.setColor(Color.WHITE);
    CIRCLE_CROP_WHITE_PAINT.setStyle(Paint.Style.STROKE);
    CIRCLE_CROP_WHITE_PAINT.setAntiAlias(true);
    CIRCLE_CROP_WHITE_PAINT.setStrokeWidth(STROKE_WIDTH);
    //CIRCLE_CROP_WHITE_PAINT.setStrokeCap(Paint.Cap.ROUND);
    CIRCLE_CROP_WHITE_PAINT.setDither(true);
}

public static Bitmap circleCrop(@NonNull BitmapPool pool, @NonNull Bitmap inBitmap,
                                int destWidth, int destHeight) {
    int destMinEdge = Math.min(destWidth, destHeight);
    float radius = destMinEdge / 2f;

    int srcWidth = inBitmap.getWidth();
    int srcHeight = inBitmap.getHeight();

    float scaleX = destMinEdge / (float) srcWidth;
    float scaleY = destMinEdge / (float) srcHeight;
    float maxScale = Math.max(scaleX, scaleY);

    float scaledWidth = maxScale * srcWidth;
    float scaledHeight = maxScale * srcHeight;
    float left = (destMinEdge - scaledWidth) / 2f;
    float top = (destMinEdge - scaledHeight) / 2f;

    RectF destRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);

    // Alpha is required for this transformation.
    Bitmap toTransform = getAlphaSafeBitmap(pool, inBitmap);

    Bitmap.Config outConfig = getAlphaSafeConfig(inBitmap);
    Bitmap result = pool.get(destMinEdge, destMinEdge, outConfig);
    result.setHasAlpha(true);

    BITMAP_DRAWABLE_LOCK.lock();
    try {
        Canvas canvas = new Canvas(result);
        // Draw a circle
        canvas.drawCircle(radius, radius, radius, CIRCLE_CROP_SHAPE_PAINT);
        // Draw the bitmap in the circle
        canvas.drawBitmap(toTransform, null, destRect, CIRCLE_CROP_BITMAP_PAINT);
        // Draw a white
        /************************描边*********************/
        float borderRadius = radius - (STROKE_WIDTH / 2);
        canvas.drawCircle(radius, radius, borderRadius, CIRCLE_CROP_WHITE_PAINT);
        /************************描边*********************/
        clear(canvas);
    } finally {
        BITMAP_DRAWABLE_LOCK.unlock();
    }

    if (!toTransform.equals(inBitmap)) {
        pool.put(toTransform);
    }

    return result;
}

public class CircleCropWhite extends CircleCrop {
    @Override
    protected Bitmap transform(
            @NonNull BitmapPool pool, @NonNull Bitmap toTransform, int outWidth, int outHeight) {
        return TransformationUtils.circleCrop(pool, toTransform, outWidth, outHeight);
    }
}

使用：

GlideApp.with(context)
        .load(image_url)
        .transforms(new CircleCropWhite())
        .into(image_view);

参考资料：

Glide 4.0 实现圆形+描边