以防忘記，做個記錄。

類：LauncherIcons.java

對圖示進行縮放處理的函式：

public static Bitmap createIconBitmap(Drawable icon, Context context, float scale) {
        synchronized (sCanvas) {
            final int iconBitmapSize = LauncherAppState.getIDP(context).iconBitmapSize;
			float scaleM = (iconBitmapSize-iconBitmapSize*scale)/2;
            int width = iconBitmapSize;
            int height = iconBitmapSize;


            if (icon instanceof PaintDrawable) {
                PaintDrawable painter = (PaintDrawable) icon;
                painter.setIntrinsicWidth(width);
                painter.setIntrinsicHeight(height);
            } else if (icon instanceof BitmapDrawable) {
                // Ensure the bitmap has a density.
                BitmapDrawable bitmapDrawable = (BitmapDrawable) icon;
                Bitmap bitmap = bitmapDrawable.getBitmap();
                if (bitmap != null && bitmap.getDensity() == Bitmap.DENSITY_NONE) {
                    bitmapDrawable.setTargetDensity(context.getResources().getDisplayMetrics());
                }
            }


            int sourceWidth = icon.getIntrinsicWidth();
            int sourceHeight = icon.getIntrinsicHeight();
            if (sourceWidth > 0 && sourceHeight > 0) {
                // Scale the icon proportionally to the icon dimensions
                final float ratio = (float) sourceWidth / sourceHeight;
                if (sourceWidth > sourceHeight) {
                    height = (int) (width / ratio);
                } else if (sourceHeight > sourceWidth) {
                    width = (int) (height * ratio);
                }
            }
            // no intrinsic size --> use default size
            int textureWidth = iconBitmapSize;
            int textureHeight = iconBitmapSize;


            Bitmap bitmap = Bitmap.createBitmap(textureWidth, textureHeight,
                    Bitmap.Config.ARGB_8888);
            final Canvas canvas = sCanvas;
            canvas.setBitmap(bitmap);


            final int left = (textureWidth-width) / 2;
            final int top = (textureHeight-height) / 2;


            sOldBounds.set(icon.getBounds());
            if (Utilities.ATLEAST_OREO && icon instanceof AdaptiveIconDrawable) {
                int offset = Math.max((int)(ShadowGenerator.BLUR_FACTOR * iconBitmapSize),
                        Math.min(left, top));
                int size = Math.max(width, height);
                icon.setBounds(offset, offset, size, size);
            } else {
                icon.setBounds(left, top, left+width, top+height);
            }
            canvas.save(Canvas.MATRIX_SAVE_FLAG);
 

             //對圖示進行縮放處理，顯示為固定大小
            canvas.scale(scale, scale, textureWidth / 2, textureHeight / 2);
            icon.draw(canvas);
            canvas.restore();
            icon.setBounds(sOldBounds);
            canvas.setBitmap(null);
			
        //return bitmap;

        //返回已經過處理的圓角bitmap  
	return getRoundedBitmap(bitmap, scaleM);
        }
    }
 

圓角處理函式：

public static Bitmap getRoundedBitmap(Bitmap mBitmap, float scaleM){  
        Bitmap bgBitmap = Bitmap.createBitmap(mBitmap.getWidth(), mBitmap.getHeight(), Bitmap.Config.ARGB_8888);    
        
        Canvas mCanvas = sCanvas;
	mCanvas.setBitmap(bgBitmap);    
        Paint mPaint = new Paint(); 
	RectF mRectM = new RectF(scaleM, scaleM, mBitmap.getWidth()-scaleM, mBitmap.getHeight()-scaleM); //設定剪裁圓角的區域		
        Rect mRect = new Rect(0, 0, mBitmap.getWidth(), mBitmap.getHeight());    
        RectF mRectF = mRectM;    
         
        float roundPx = 15;    //圓角半徑
        mPaint.setAntiAlias(true);    
       //Log.d("wy"+TAG,"mBitmap.getWidth()="+mBitmap.getWidth()+", mBitmap.getHeight()="+mBitmap.getHeight());
        mCanvas.drawRoundRect(mRectF, roundPx, roundPx, mPaint);           
        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));         
        mCanvas.drawBitmap(mBitmap, mRect, mRect, mPaint);    
        return bgBitmap;    
    }