android.graphics.Paint#getXfermode ( )源码实例Demo

@Override
protected void onDraw(Canvas canvas) {
    Drawable myDrawable = getDrawable();
    if (myDrawable!=null && myDrawable instanceof BitmapDrawable && mCornerRadius > 0) {
        rectF.set(myDrawable.getBounds());
        int prevCount = canvas.saveLayer(rectF, null, Canvas.ALL_SAVE_FLAG);
        getImageMatrix().mapRect(rectF);

        Paint paint = ((BitmapDrawable) myDrawable).getPaint();
        paint.setAntiAlias(true);
        paint.setColor(DEFAULT_COLOR);
        Xfermode prevMode = paint.getXfermode();

        canvas.drawARGB(DEFAULT_RGB, DEFAULT_RGB, DEFAULT_RGB, DEFAULT_RGB);
        canvas.drawRoundRect(rectF, mCornerRadius, mCornerRadius, paint);

        paint.setXfermode(porterDuffXfermode);
        super.onDraw(canvas);

        paint.setXfermode(prevMode);
        canvas.restoreToCount(prevCount);
    } else {
        super.onDraw(canvas);
    }
}
 

@Override
public int getOpacity() {
    final Paint bPaint = mBackgroundPaint;
    final Paint fPaint = mForegroundPaint;
    if (bPaint.getXfermode() == null && fPaint.getXfermode() == null) {
        final int alpha = Color.alpha(fPaint.getColor());
        if (alpha == 0) {
            return PixelFormat.TRANSPARENT;
        }
        if (alpha == 255) {
            return PixelFormat.OPAQUE;
        }
    }
    // not sure, so be safe
    return PixelFormat.TRANSLUCENT;
}
 

@Override
public void draw(Canvas canvas) {
    final Paint paint = mPaint;
    final int prevAlpha = paint.getAlpha();
    paint.setAlpha(Ui.modulateAlpha(prevAlpha, getAlpha()));
    // only draw shape if it may affect output
    if (paint.getAlpha() != 0 || paint.getXfermode() != null /*|| paint.hasShadowLayer()*/) {
        final boolean clearColorFilter;
        if (mTintFilter != null && paint.getColorFilter() == null) {
            paint.setColorFilter(mTintFilter);
            clearColorFilter = true;
        } else {
            clearColorFilter = false;
        }

        // call draw
        draw(canvas, mPaint);

        if (clearColorFilter) {
            paint.setColorFilter(null);
        }
    }
    // restore
    paint.setAlpha(prevAlpha);
}
 

@Override
public int getOpacity() {
    final Paint circlePaint = mCirclePaint;
    final Paint ringPaint = mRingPaint;
    if (circlePaint.getXfermode() == null && ringPaint.getXfermode() == null) {
        final int alpha = Color.alpha(getColor());
        if (alpha == 0) {
            return PixelFormat.TRANSPARENT;
        }
        if (alpha == 255) {
            return PixelFormat.OPAQUE;
        }
    }
    // not sure, so be safe
    return PixelFormat.TRANSLUCENT;
}
 

@Override
public void draw(@NonNull Rect outRect, @NonNull Canvas canvas, CharSequence text, @IntRange(from = 0) int start, @IntRange(from = 0) int end, float x, int top, int y, int bottom, @NonNull Paint paint) {
    if (bitmap == null) {
        bitmap = Bitmap.createBitmap(frame.right - frame.left, frame.bottom - frame.top, Bitmap.Config.ARGB_8888);
        bitmapCanvas = new Canvas(bitmap);
    }
    bitmapCanvas.drawColor(Color.BLACK, PorterDuff.Mode.CLEAR);
    bitmapCanvas.translate(-x, 0);
    super.draw(outRect, bitmapCanvas, text, start, end, x, top, y, bottom, paint);
    Xfermode oldXfermode = paint.getXfermode();
    paint.setXfermode(this.xfermode);
    srcGroup.draw(outRect, bitmapCanvas, text, start, end, x, top, y, bottom, paint);
    paint.setXfermode(oldXfermode);
    canvas.drawBitmap(bitmap, x, 0, null);
}
 

@Override
public void draw(@NonNull Rect outRect, @NonNull Canvas canvas, CharSequence text, @IntRange(from = 0) int start, @IntRange(from = 0) int end, float x, int top, int y, int bottom, @NonNull Paint paint) {
    if (bitmap == null) {
        bitmap = Bitmap.createBitmap(frame.right - frame.left, frame.bottom - frame.top, Bitmap.Config.ARGB_8888);
        bitmapCanvas = new Canvas(bitmap);
    }
    bitmapCanvas.drawColor(Color.BLACK, PorterDuff.Mode.CLEAR);
    bitmapCanvas.translate(-x, 0);
    super.draw(outRect, bitmapCanvas, text, start, end, x, top, y, bottom, paint);
    Xfermode oldXfermode = paint.getXfermode();
    paint.setXfermode(this.xfermode);
    srcGroup.draw(outRect, bitmapCanvas, text, start, end, x, top, y, bottom, paint);
    paint.setXfermode(oldXfermode);
    canvas.drawBitmap(bitmap, x, 0, null);
}
 

@Override
public int getOpacity() {
    final Paint p = mPaint;
    if (p.getXfermode() == null) {
        final int alpha = p.getAlpha();
        if (alpha == 0) {
            return PixelFormat.TRANSPARENT;
        }
        if (alpha == 255) {
            return PixelFormat.OPAQUE;
        }
    }
    // not sure, so be safe
    return PixelFormat.TRANSLUCENT;
}