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我可以編寫一個應用程序來繪製的油漆,但我有一個問題開始從圓的Android
我要開始從圓拉絲, 我的出發點永遠是圓的,我怎麼能做到這一點?
現在我可以從任何一點借鑑,我試圖找到在屏幕的中間,但它沒有工作
public CanvasView(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
path = new Path();
paint = new Paint();
paint.setColor(Color.RED);
paint.setAntiAlias(true);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(20f);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mbitmap = Bitmap.createBitmap(w,h,Bitmap.Config.ARGB_8888);
mcanvas = new Canvas(mbitmap);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
int a = metrics.widthPixels; // to get width of the screen
int b = metrics.heightPixels;
canvas.drawCircle(a/2,((b/2)-160),50, paint);
if ((canDraw)) {
canvas.drawPath(path, paint);
}
}
private void startTouch (float x , float y){
if ((canDraw)) {
path.moveTo(x,y);
mX = x;
mY = y ;
}}
public void moveTouche (float x,float y) {
if ((canDraw)) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if(dx >= Tolerance || dy >= Tolerance){
path.quadTo(mX,mY,(x+mX)/2,(y+mY)/2);
mX = x ;
mY = y;
}}
}
private void upTouch(){
if ((canDraw)) {
path.lineTo(mX,mY);
}}
@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
startTouch(x,y);
invalidate();
break ;
case MotionEvent.ACTION_UP:
upTouch();
invalidate();
break ;
case MotionEvent.ACTION_MOVE:
moveTouche(x,y);
invalidate();
break;
}
return true ;
}
}
所以我嘗試與此 '私人布爾touchIsInsideCircle(浮動的x,浮子y)的{ int a = metrics.widthPixels; //獲取屏幕寬度 int b = metric.heightPixels; return(x < a/2 && x > a/2 && y <((b/2)-160)&& y>((b/2)-160))}' 這些是圓的座標,繪圖始終開始的問題與x == 0和y == 0,每次我觸摸屏幕點連接 – CamlX