Since I did not find a way to rotate the canvas and always display the drawing I'm calculating the position of the rotated points myself now. For this I found the following information really helpful:
http://stackoverflow.com/questions/786472/rotate-a-point-by-an-angle Axel On 7 Mrz., 10:55, axel <[email protected]> wrote: > I have create a subclass of View and overwritten onDraw() - see some > test code below. > It draws a line consisting of some points. Before the line is drawn > the canvas is rotated and restore after the drawing. > The angle by which the canvas is rotated increases by 5 degrees every > time onDraw() is called. > The view is invalidated about once a second causing the view to be > redrawn. > Due to the rotated canvas the line drawn looks like a clock hand > rotating counter-clockwise. > This works - but not always. Sometimes the line is not drawn for one > or more seconds, although I know from the log statement that onDraw() > was called. Sometimes means: The line may be not shown after 8 > seconds, then again after 35 seconds and so on. > If the canvas is not rotated the problem does not occur. > This also happens when I use a SurfaceView instead of a View. > It does not only occur in the simulator but also on my G1 - both using > Android 1.6. > > Axel > > public class NoMapView extends View { > private int angle; > private Paint paint; > > public NoMapView(Context context) { > super(context); > } > > public NoMapView(Context context, AttributeSet attrs, int > defStyle) { > super(context, attrs, defStyle); > } > > public NoMapView(Context context, AttributeSet attrs) { > super(context, attrs); > } > > @Override > protected void onDraw(Canvas canvas) { > super.onDraw(canvas); > > if(paint == null) { > paint = new Paint(Paint.ANTI_ALIAS_FLAG); > paint.setAntiAlias(true); > paint.setColor(Color.MAGENTA); > paint.setStyle(Paint.Style.FILL); > paint.setStrokeWidth(1); > } > > Point center = new Point(getWidth() / 2, getHeight() / 2); > canvas.save(); > > canvas.rotate(-angle, center.x, center.y); > for(int i=160; i<180; i++) { > canvas.drawPoint(i, i, paint); > } > canvas.restore(); > > // log.info("angle=" + angle); > > angle+=5; > if(angle == 360) { > angle = 0; > } > } > > } > > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
