【发布时间】：2013-03-19 04:10:55
【问题描述】：
这是绘图和撤消的代码，但无法加入擦除。
它要么是绘图 + 擦除或绘图 + 撤消，但不能是其中三个。
public class Drawing extends View {
private Paint mPaint, mBitmapPaint;
private Bitmap mBitmap;
private Canvas mCanvas;
private Path mPath;
private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;
private int color, size, state;
private ArrayList<Path> paths = new ArrayList<Path>();
private ArrayList<Path> undonePaths = new ArrayList<Path>();
private ArrayList<Integer> colors = new ArrayList<Integer>();
private ArrayList<Integer> sizes = new ArrayList<Integer>();
public Drawing(Context c) {
super(c);
}
public Drawing(Context c,int width, int height, int size, int color, int state) {
super(c);
mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
mCanvas = new Canvas(mBitmap);
mPath = new Path();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
// mBitmapPaint = new Paint(Paint.DITHER_FLAG);
// mBitmapPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
setColor(color);
setSize(size);
setState(state);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
// canvas.drawColor(Color.TRANSPARENT);
// canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
//
// if (state == 0)
// mBitmap.eraseColor(Color.TRANSPARENT);
for (int i = 0; i < paths.size(); i++) {
mPaint.setColor(colors.get(i));
mPaint.setStrokeWidth(sizes.get(i));
canvas.drawPath(paths.get(i), mPaint);
}
mPaint.setColor(color);
mPaint.setStrokeWidth(size);
canvas.drawPath(mPath, mPaint);
}
public void setColor(int color) {
this.color = color;
}
public void setSize(int size) {
this.size = size;
}
public void setState(int state) {
this.state = state;
// if (state == 0)
// mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
// else
// mPaint.setXfermode(null);
}
public void onClickUndo() {
if (paths.size() > 0) {
undonePaths.add(paths.remove(paths.size() - 1));
sizes.remove(sizes.size() - 1);
colors.remove(colors.size() - 1);
invalidate();
}
}
private void touch_start(float x, float y) {
undonePaths.clear();
mPath.reset();
mPath.moveTo(x, y);
mX = x;
mY = y;
}
private void touch_move(float x, float y) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
mX = x;
mY = y;
}
}
private void touch_up() {
mPath.lineTo(mX, mY);
mCanvas.drawPath(mPath, mPaint);
colors.add(color);
sizes.add(size);
paths.add(mPath);
mPath = new Path();
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touch_start(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE:
touch_move(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
touch_up();
invalidate();
break;
}
return true;
}
}
我尝试将颜色设置为透明，但这没有意义，因为不更改像素而是创建新路径。
【问题讨论】：
-
不适合，不能使用erasecolor，因为我的是擦除它想要的东西而不是整个位图
标签： java android erase undo-redo paint