如何使位图变得透明？
如何使位图变得透明？
提问于 2013-02-26 16:00:24
/**
* @param bitmap
* The source bitmap.
* @param opacity
* a value between 0 (completely transparent) and 255 (completely
* opaque).
* @return The opacity-adjusted bitmap. If the source bitmap is mutable it
* will be adjusted and returned, otherwise a new bitmap is created.
* Source : http://stackoverflow.com/questions/7392062/android-
* semitransparent-bitmap-background-is-black/14858913#14858913
*/
private Bitmap adjustOpacity(Bitmap bitmap, int opacity) {
Bitmap mutableBitmap = bitmap.isMutable() ? bitmap : bitmap.copy(Bitmap.Config.ARGB_8888, true);
Canvas canvas = new Canvas(mutableBitmap);
int colour = (opacity & 0xFF) << 24;
canvas.drawColor(colour, PorterDuff.Mode.DST_IN);
return mutableBitmap;
}使用adjustOpacity，我使ImageView的Bitmap是半透明的。
Bitmap newBitmap = adjustOpacity(orignalBitmap, 10);
view.setImageBitmap(newBitmap);
view.setBackgroundColor(Color.WHITE);但是，Imageview在不变白之前表现出更深的颜色。如何用Bitmap制作半透明(白色背景)的图像视图
Stack Overflow用户
发布于 2020-01-29 05:23:48
Add方法
Bitmap bmp; DrawView DrawView;
private static Bitmap makeTransparentBitmap(Bitmap bmp, int alpha) {
Bitmap transBmp = Bitmap.createBitmap(bmp.getWidth(),
bmp.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(transBmp);
final Paint paint = new Paint();
paint.setAlpha(alpha);
canvas.drawBitmap(bmp, 0, 0, paint);
return transBmp;
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(Color.rgb(43,44,45));
bmp = BitmapFactory.decodeResource(getResources(), R.drawable.mouse);
canvas.drawBitmap(bmp, pos_x, pos_y, null);
}您的活动：
bmp = makeTransparentBitmap( bmp, 122 );
DrawView.invalidate();DrawView是
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
DrawView = new DrawView(this);
setContentView( DrawView );
}我找到了这个答案here
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原文链接：
https://stackoverflow.com/questions/15084128
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