问题描述
我有一个ViewGroup（特别是一个FrameLayout），它应该具有流畅的填充效果，我使用一条动画路径很好地显示了下面的子视图。
问题是，在液体填充线上方，我需要用相反的两种颜色显示子项。 （Black <-> White）如果不简单地迭代位图，就看不到实现此目的的方法，该位图提供了非常糟糕的副本并带有很多别名，并且渲染速度太慢。
这是我在dispatchDraw中的当前功能的简化版本：
@Override
protected void dispatchDraw(Canvas canvas)
{
filter.setXfermode(null);
if (subBitmap == null || mLastWidth != mWidth) {
subBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
subCanvas = new Canvas(subBitmap);
}
super.dispatchDraw(subCanvas);
if (mLiquidPaint == null || mLiquidPath == null || waveOval.size() == 0 || bitmapPixels == null || !mLiquidAnimator.isRunning()) {
canvas.drawBitmap(subBitmap, 0, 0, filter);
return;
}
if (revealBitmap == null || mLastWidth != mWidth) {
revealBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
revealCanvas = new Canvas(revealBitmap);
}
if (mLastWidth != mWidth) {
calculateLiquid();
mLastWidth = mWidth;
}
int yOffset = mFillOffset;
int xOffset = ellipseWidth * -1;
PointF firstPoint = new PointF();
PointF lastPoint = new PointF();
PointF nextPoint = new PointF();
Pair<Integer, Float> nextWavePoint = wavePoints.get(0);
PointF ovalPoint = waveOval.get((nextWavePoint.first + mWaveOffset) % waveOval.size());
lastPoint.set(xOffset + nextWavePoint.second + ovalPoint.x, yOffset + ovalPoint.y);
mLiquidPath.moveTo(lastPoint.x, lastPoint.y);
firstPoint.set(lastPoint);
for (int i = 1; i < wavePoints.size(); i++) {
nextWavePoint = wavePoints.get(i);
ovalPoint = waveOval.get((nextWavePoint.first + mWaveOffset) % waveOval.size());
nextPoint.set(xOffset + nextWavePoint.second + ovalPoint.x, ovalPoint.y + yOffset);
mLiquidPath.lineTo(nextPoint.x, nextPoint.y);
lastPoint.set(nextPoint);
}
mLiquidPath.lineTo(getWidth(), lastPoint.y);
mLiquidPath.lineTo(getWidth(), getHeight());
mLiquidPath.lineTo(0, getHeight());
mLiquidPath.lineTo(firstPoint.x, firstPoint.y);
//This definitely draws a nice liquid path that fills from the bottom up.
revealCanvas.drawPath(mLiquidPath, mLiquidPaint);
//The next two lines successfully reveal the views underneath
filter.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));
revealCanvas.drawBitmap(subBitmap, 0, 0, filter);
filter.setXfermode(null);
filter.setColorFilter(null);
canvas.drawBitmap(revealBitmap, 0, 0, filter);
}
我尝试了无数种不同的ColorFilters和传输模式。 孩子们不能让背景透明，让我做更简单的颜色替换。
1楼
最后，使用ColorMatrixColorFilter找出了问题，如下所示：
对于两种颜色color1和color2你交换它们具有以下ColorMatrix ：
float[] colorSwapMatrix = new float[] {
-1, 0, 0, 0, Color.red(color1) + Color.red(color2), //Red
0, -1, 0, 0, Color.green(color1) + Color.green(color2),//Green
0, 0, -1, 0, Color.blue(color1) + Color.blue(color2), //Blue
0, 0, 0, 1f, 0 //Alpha
}
在绘制了上面的波路径之后，将应用此方法，如下所示：
//Draw the swapped image above the wave
filter.setColorFilter(new ColorMatrixColorFilter(colorSwapMatrix));
filter.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OUT));
revealCanvas.drawBitmap(subBitmap, 0, 0, filter);
//Draw the regular image below the wave
filter.setColorFilter(null);
filter.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_ATOP));
revealCanvas.drawBitmap(subBitmap, 0, 0, filter);
//Draw the combined image onto the canvas
filter.setXfermode(null);
filter.setColorFilter(null);
canvas.drawBitmap(revealBitmap, 0, 0, filter);