C# RectF.CenterX方法代码示例

        public override void Draw(Android.Graphics.Canvas canvas)
        {
            base.Draw(canvas);

            var rect = new RectF(0,0,300,300);
            switch (TheShape)
            {
                case Shape.Circle:
                    canvas.DrawOval(rect, new Paint() { Color = Color.Aqua });
                    break;
                case Shape.Square:
                    canvas.DrawRect(rect, new Paint() { Color = Color.Red });
                    break;
                case Shape.Triangle:
                    var path = new Path();
                    path.MoveTo(rect.CenterX(), 0);
                    path.LineTo(0, rect.Height());
                    path.LineTo(rect.Width(), rect.Height());
                    path.Close();

                    var paint = new Paint() {Color = Color.Magenta};
                    paint.SetStyle(Paint.Style.Fill);
                    canvas.DrawPath(path, paint);
                    break;

                default:
                    throw new ArgumentOutOfRangeException();
            }
        }

        protected override void OnDraw(Android.Graphics.Canvas canvas)
        {
            var rect = new RectF(0, 0, 300, 300);
            switch (Shape)
            {
                case Shape.Circle:
                    canvas.DrawOval(rect, new Paint() { Color = Color.CornflowerBlue });
                    break;
                case Shape.Square:
                    canvas.DrawRect(rect, new Paint() { Color = Color.Crimson });
                    break;
                case Shape.Triangle:

                    var path = new Path();
                    path.MoveTo(rect.CenterX(), rect.Top);
                    path.LineTo(rect.Left, rect.Bottom);
                    path.LineTo(rect.Right, rect.Bottom);
                    path.Close();
                    var paint = new Paint() {Color = Color.Crimson};
                    paint.Color = Color.Gold;
                    paint.SetStyle(Paint.Style.Fill);
                    canvas.DrawPath(path, paint);
                    break;
                default:
                    throw new ArgumentOutOfRangeException();
            }
        }

    public Transition(RectF srcRect, RectF dstRect, long duration, IInterpolator interpolator) {
        if (!MathUtils.HaveSameAspectRatio(srcRect, dstRect)) {
            throw new IncompatibleRatioException();
        }
        _mSrcRect = srcRect;
        _mDstRect = dstRect;
        _mDuration = duration;
        _mInterpolator = interpolator;

        // Precomputes a few variables to avoid doing it in onDraw().
        _mWidthDiff = dstRect.Width() - srcRect.Width();
        _mHeightDiff = dstRect.Height() - srcRect.Height();
        _mCenterXDiff = dstRect.CenterX() - srcRect.CenterX();
        _mCenterYDiff = dstRect.CenterY() - srcRect.CenterY();
    }

		//Configures the neccesary matrix transformation to apply to the textureView
		public void configureTransform(int viewWidth, int viewHeight) 
		{
			if (null == Activity || null == previewSize || null == textureView) 
				return;

			int rotation = (int)Activity.WindowManager.DefaultDisplay.Rotation;
			var matrix = new Matrix ();
			var viewRect = new RectF (0, 0, viewWidth, viewHeight);
			var bufferRect = new RectF (0, 0, previewSize.Height, previewSize.Width);
			float centerX = viewRect.CenterX();
			float centerY = viewRect.CenterY();
			if ((int)SurfaceOrientation.Rotation90 == rotation || (int)SurfaceOrientation.Rotation270 == rotation) { 
				bufferRect.Offset ((centerX - bufferRect.CenterX()), (centerY - bufferRect.CenterY()));
				matrix.SetRectToRect (viewRect, bufferRect, Matrix.ScaleToFit.Fill);
				float scale = System.Math.Max (
					(float)viewHeight / previewSize.Height,
					(float)viewHeight / previewSize.Width);
				matrix.PostScale (scale, scale, centerX, centerY);
				matrix.PostRotate (90 * (rotation - 2), centerX, centerY);
			}
			textureView.SetTransform (matrix);
		}

		/// <summary>
		/// Configures the necessary transformation to mTextureView.
		/// This method should be called after the camera preciew size is determined in openCamera, and also the size of mTextureView is fixed
		/// </summary>
		/// <param name="viewWidth">The width of mTextureView</param>
		/// <param name="viewHeight">VThe height of mTextureView</param>
		private void ConfigureTransform(int viewWidth, int viewHeight)
		{
			Activity activity = Activity;
			if (mTextureView == null || mPreviewSize == null || activity == null) {
				return;
			}

			SurfaceOrientation rotation = activity.WindowManager.DefaultDisplay.Rotation;
			Matrix matrix = new Matrix ();
			RectF viewRect = new RectF (0, 0, viewWidth, viewHeight);
			RectF bufferRect = new RectF (0, 0, mPreviewSize.Width, mPreviewSize.Height);
			float centerX = viewRect.CenterX();
			float centerY = viewRect.CenterY();
			if (rotation == SurfaceOrientation.Rotation90 || rotation == SurfaceOrientation.Rotation270) {
				bufferRect.Offset (centerX - bufferRect.CenterX(), centerY - bufferRect.CenterY());
				matrix.SetRectToRect (viewRect, bufferRect, Matrix.ScaleToFit.Fill);
				float scale = Math.Max ((float)viewHeight / mPreviewSize.Height, (float)viewWidth / mPreviewSize.Width);
				matrix.PostScale (scale, scale, centerX, centerY);
				matrix.PostRotate (90 * ((int)rotation - 2), centerX, centerY);
			}
			mTextureView.SetTransform (matrix);
		}

 public override void OnDraw(Canvas canvas, RectF bounds, float degreeSelected)
 {
     canvas.DrawRect(bounds,BackgroundPaint);
     canvas.DrawText(Text, bounds.CenterX(), bounds.CenterY() - (TextPaint.Descent() + TextPaint.Ascent()) / 2, TextPaint);
 }

		protected override void OnSizeChanged (int w, int h, int oldW, int oldH)
		{	
			HEIGHT = h;
			WIDTH = w;

			HALF_WIDTH = (int)Math.Round ((Double)w / 2);
			HALF_HEIGHT = (int)(Math.Round ((Double)h / 2));

			//int OFFSET = mCenterOval.Width () / 3.0f;

			mCenterOval = new RectF ();
			//float OFFSET = 140f;
			//Change the OFFSET to relative value according to the screen width
			float OFFSET = WIDTH / 5;
			//mCenterOval.Set (OFFSET, OFFSET, WIDTH - OFFSET, WIDTH - OFFSET);
			//move the mCenterOval a little bit up
			mCenterOval.Set (OFFSET, OFFSET * (float)0.5, WIDTH - OFFSET, WIDTH - (float)1.5 * OFFSET);

			mCx = (int)Math.Round (mCenterOval.CenterX ());
			mCy = (int)Math.Round (mCenterOval.CenterY ());
			mRadius = (int)Math.Round (mCenterOval.Width () / 2.0f);

			mInnerCircleRadius = mRadius - (mPaint.StrokeWidth * 0.9f);

			updateCircleCoordinate (mCx, 0);
		}