Draw smoothly scaled bitmaps on Canvas

Question

This is how I draw Bitmap on Canvas in my Android app:

canvas.save(); canvas.scale(scale, scale, x, y); canvas.drawBitmap(bitmap, x, y, null); canvas.restore(); 

However the Bitmap is not scaled smoothly, no anti-aliasing is performed. How can I enable anti-aliasing?

Answer 1

Try this:

Paint paint = new Paint(); paint.setAntiAlias(true); paint.setFilterBitmap(true); paint.setDither(true);  canvas.drawBitmap(bitmap, x, y, paint); 

Answer 2

Both Paint paint = new Paint(Paint.FILTER_BITMAP_FLAG); or paint.setFilterBitmap(true); worked for me but be very careful, on my game it cut down the FPS from 30FPS to 17FPS only. So if it is a mission critical drawing like in a game you better scale the image at loading time. Which I did in the following manner:

public Bitmap getImage (int id, int width, int height) {     Bitmap bmp = BitmapFactory.decodeResource( getResources(), id );     Bitmap img = Bitmap.createScaledBitmap( bmp, width, height, true );     bmp.recycle();     return img; }