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：
使用 Canvas 和 Paint 來繪制
使用 Android.support.v4.graphics.drawable.RoundedBitmapDrawable
實現圓形圖片：
/**
?*
?* Glide 圓形圖片 Transform
?*/
publicclassGlideCircleTransform extendsBitmapTransformation {
??publicGlideCircleTransform(Context context) {
????super(context);
??}
??@Override
??protectedBitmap transform(BitmapPool pool, Bitmap toTransform, intoutWidth, intoutHeight) {
????returncircleCrop(pool, toTransform);
??}
??privatestaticBitmap circleCrop(BitmapPool pool, Bitmap source) {
????if(source == null) returnnull;
????intsize = Math.min(source.getWidth(), source.getHeight());
????intx = (source.getWidth() - size) / 2;
????inty = (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 = newCanvas(result);
????Paint paint = newPaint();
????paint.setShader(newBitmapShader(squared, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));
????paint.setAntiAlias(true);
????floatr = size / 2f;
????canvas.drawCircle(r, r, r, paint);
????returnresult;
??}
??@Override
??publicString getId() {
????returngetClass().getName();
??}
}
實現圓角圖片：
/**
?* Glide 圓角 Transform
?*/
publicclassGlideRoundTransform extendsBitmapTransformation {
??privatestaticfloatradius = 0f;
??/**
?* 構造函數 默認圓角半徑 4dp
?*
?* @param context Context
?*/
??publicGlideRoundTransform(Context context) {
????this(context, 4);
??}
??/**
?* 構造函數
?*
?* @param context Context
?* @param dp 圓角半徑
?*/
??publicGlideRoundTransform(Context context, intdp) {
????super(context);
????radius = Resources.getSystem().getDisplayMetrics().density * dp;
??}
??@Override
??protectedBitmap transform(BitmapPool pool, Bitmap toTransform, intoutWidth, intoutHeight) {
????returnroundCrop(pool, toTransform);
??}
??privatestaticBitmap roundCrop(BitmapPool pool, Bitmap source) {
????if(source == null) returnnull;
????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 = newCanvas(result);
????Paint paint = newPaint();
????paint.setShader(newBitmapShader(source, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));
????paint.setAntiAlias(true);
????RectF rectF = newRectF(0f, 0f, source.getWidth(), source.getHeight());
????canvas.drawRoundRect(rectF, radius, radius, paint);
????returnresult;
??}
??@Override
??publicString getId() {
????returngetClass().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
???publicstaticvoidloadRoundImage(finalContext context, String url,finalImageView imageView){
?????Glide.with(context)
?????????.load(url)
?????????.asBitmap()
?????????.placeholder(placeholder)
?????????.error(placeholder)
?????????.diskCacheStrategy(DiskCacheStrategy.ALL) //設置緩存
?????????.into(newBitmapImageViewTarget(imageView){
???????????@Override
???????????protectedvoidsetResource(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
??publicstaticvoidloadCirclePic(finalContext context, String url, finalImageView imageView) {
????Glide.with(context)
????????.load(url)
????????.asBitmap()
????????.placeholder(placeholder)
????????.error(placeholder)
????????.diskCacheStrategy(DiskCacheStrategy.ALL) //設置緩存
????????.into(newBitmapImageViewTarget(imageView) {
??????????@Override
??????????protectedvoidsetResource(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
publicstaticBitmap drawableToBitmap(Drawable drawable) {
????// 取 drawable 的長寬
????intw = drawable.getIntrinsicWidth();
????inth = 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 = newCanvas(bitmap);
????drawable.setBounds(0, 0, w, h);
????// 把 drawable 內容畫到畫布中
????drawable.draw(canvas);
????returnbitmap;
??}
/**
?* 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腳本之家。
