一、簡介：
介紹兩種使用 BitmapTransformation 來實現 Glide 加載圓形圖片和圓角圖片的方法。Glide 并不能直接支持 Round Pictures ，需要使用 BitmapTransformation 來進行處理。
二、網上的實現方式
這里介紹下網上常見的方式和使用 RoundedBitmapDrawable 兩種方法，本質上是差不多的：
實現圓形圖片：
/** * * Glide 圓形圖片 Transform */public class GlideCircleTransform extends BitmapTransformation { public GlideCircleTransform(Context context) { super(context); } @Override protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) { return circleCrop(pool, toTransform); } private static Bitmap circleCrop(BitmapPool pool, Bitmap source) { if (source == null) return null; int size = Math.min(source.getWidth(), source.getHeight()); int x = (source.getWidth() - size) / 2; int y = (source.getHeight() - size) / 2; Bitmap squared = Bitmap.createBitmap(source, x, y, size, size); Bitmap result = pool.get(size, size, Bitmap.Config.ARGB_8888); if (result == null) { result = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888); } Canvas canvas = new Canvas(result); Paint paint = new Paint(); paint.setShader(new BitmapShader(squared, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP)); paint.setAntiAlias(true); float r = size / 2f; canvas.drawCircle(r, r, r, paint); return result; } @Override public String getId() { return getClass().getName(); }}實現圓角圖片：
/** * Glide 圓角 Transform */public class GlideRoundTransform extends BitmapTransformation { private static float radius = 0f; /** * 構造函數 默認圓角半徑 4dp * * @param context Context */ public GlideRoundTransform(Context context) { this(context, 4); } /** * 構造函數 * * @param context Context * @param dp 圓角半徑 */ public GlideRoundTransform(Context context, int dp) { super(context); radius = Resources.getSystem().getDisplayMetrics().density * dp; } @Override protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) { return roundCrop(pool, toTransform); } private static Bitmap roundCrop(BitmapPool pool, Bitmap source) { if (source == null) return null; Bitmap result = pool.get(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888); if (result == null) { result = Bitmap.createBitmap(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888); } Canvas canvas = new Canvas(result); Paint paint = new Paint(); paint.setShader(new BitmapShader(source, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP)); paint.setAntiAlias(true); RectF rectF = new RectF(0f, 0f, source.getWidth(), source.getHeight()); canvas.drawRoundRect(rectF, radius, radius, paint); return result; } @Override public String getId() { return getClass().getName() + Math.round(radius); }}三、筆者比較喜歡的簡便的實現方式
//加載圓角圖片 public static void loadRoundImage(final Context context, String url,final ImageView imageView){ Glide.with(context) .load(url) .asBitmap() .placeholder(placeholder) .error(placeholder) .diskCacheStrategy(DiskCacheStrategy.ALL) //設置緩存 .into(new BitmapImageViewTarget(imageView){ @Override protected void setResource(Bitmap resource) { super.setResource(resource); RoundedBitmapDrawable circularBitmapDrawable = RoundedBitmapDrawableFactory.create(context.getResources(), resource); circularBitmapDrawable.setCornerRadius(10); //設置圓角弧度 imageView.setImageDrawable(circularBitmapDrawable); } }); } //加載圓形圖片 public static void loadCirclePic(final Context context, String url, final ImageView imageView) { Glide.with(context) .load(url) .asBitmap() .placeholder(placeholder) .error(placeholder) .diskCacheStrategy(DiskCacheStrategy.ALL) //設置緩存 .into(new BitmapImageViewTarget(imageView) { @Override protected void setResource(Bitmap resource) { RoundedBitmapDrawable circularBitmapDrawable = RoundedBitmapDrawableFactory.create(context.getResources(), resource); circularBitmapDrawable.setCircular(true); imageView.setImageDrawable(circularBitmapDrawable); } }); }關于drawableToBitmap的源碼的實現是這樣的
public static Bitmap drawableToBitmap(Drawable drawable) { // 取 drawable 的長寬 int w = drawable.getIntrinsicWidth(); int h = drawable.getIntrinsicHeight(); // 取 drawable 的顏色格式 Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565; // 建立對應 bitmap Bitmap bitmap = Bitmap.createBitmap(w, h, config); // 建立對應 bitmap 的畫布 Canvas canvas = new Canvas(bitmap); drawable.setBounds(0, 0, w, h); // 把 drawable 內容畫到畫布中 drawable.draw(canvas); return bitmap; }/** * RoundedBitmapDrawable 是 V4 下的一個類，不能簡單的通過：強制轉換成 BitmapDrawable * Bitmap bitmap = ((BitmapDrawable)xxx).getBitmap(); */以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。
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