C# Graphics.Rect类代码示例

        public Bitmap GetBitmapMarker(Context mContext, int resourceId, string text)
        {
            Resources resources = mContext.Resources;
            float scale = resources.DisplayMetrics.Density;
            Bitmap bitmap = BitmapFactory.DecodeResource(resources, resourceId);

            Bitmap.Config bitmapConfig = bitmap.GetConfig();

            // set default bitmap config if none
            if (bitmapConfig == null)
                bitmapConfig = Bitmap.Config.Argb8888;

            bitmap = bitmap.Copy(bitmapConfig, true);

            Canvas canvas = new Canvas(bitmap);
            Paint paint = new Paint(PaintFlags.AntiAlias);
            paint.Color = global::Android.Graphics.Color.Black;
            paint.TextSize = ((int)(14 * scale));
            paint.SetShadowLayer(1f, 0f, 1f, global::Android.Graphics.Color.White);

            // draw text to the Canvas center
            Rect bounds = new Rect();
            paint.GetTextBounds(text, 0, text.Length, bounds);
            int x = (bitmap.Width - bounds.Width()) / 2;
            int y = (bitmap.Height + bounds.Height()) / 2 - 20;

            canvas.DrawText(text, x, y, paint);

            return bitmap;
        }

		//http://egoco.de/post/19077604048/calculating-the-height-of-text-in-android
		//http://stackoverflow.com/questions/16082359/how-to-auto-adjust-text-size-on-a-multi-line-textview-according-to-the-view-max
		public SizeF MeasureString(string text, int maxWidth = 2147483647)
		{
			TextPaint paint = AndroidBrush.CreateTextPaint();
			paint.TextSize = SizeInPoints;
			paint.SetTypeface(InnerFont);

			int lineCount = 0;

			int index = 0;
			int length = text.Length;

			float[] measuredWidths = new float[]{ 0 };
			float measuredWidth = 1f;
			while(index < length - 1) 
			{
				index += paint.BreakText(text, index, length, true, maxWidth, measuredWidths);
				lineCount++;
				if (measuredWidth < measuredWidths[0]) measuredWidth = measuredWidths[0];
			}

			Rect bounds = new Rect();
			paint.GetTextBounds("Py", 0, 2, bounds);
			float height = (float)System.Math.Floor((double)lineCount * bounds.Height());

			return new SizeF (measuredWidth, height);
		}

		// If you would like to create a circle of the image set pixels to half the width of the image.
		internal static   Bitmap GetRoundedCornerBitmap(Bitmap bitmap, int pixels)
		{
			Bitmap output = null;

			try
			{
				output = Bitmap.CreateBitmap(bitmap.Width, bitmap.Height, Bitmap.Config.Argb8888);
				Canvas canvas = new Canvas(output);

				Color color = new Color(66, 66, 66);
				Paint paint = new Paint();
				Rect rect = new Rect(0, 0, bitmap.Width, bitmap.Height);
				RectF rectF = new RectF(rect);
				float roundPx = pixels;

				paint.AntiAlias = true;
				canvas.DrawARGB(0, 0, 0, 0);
				paint.Color = color;
				canvas.DrawRoundRect(rectF, roundPx, roundPx, paint);

				paint.SetXfermode(new PorterDuffXfermode(PorterDuff.Mode.SrcIn));
				canvas.DrawBitmap(bitmap, rect, rect, paint);
			}
			catch (System.Exception err)
			{
				System.Console.WriteLine ("GetRoundedCornerBitmap Error - " + err.Message);
			}

			return output;
		}

 public override void GetItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state)
 {
     if (parent.GetChildLayoutPosition(view) != 0)
     {
         outRect.Top = space;
     }
 }

		public static Bitmap getRoundedCroppedBitmap(Bitmap bitmap, int radius) {
			Bitmap finalBitmap;
			if (bitmap.Width != radius || bitmap.Height!= radius)
				finalBitmap = Bitmap.CreateScaledBitmap(bitmap, radius, radius,
					false);
			else
				finalBitmap = bitmap;
			Bitmap output = Bitmap.CreateBitmap(finalBitmap.Width,
				finalBitmap.Height, Bitmap.Config.Argb8888);
			Canvas canvas = new Canvas(output);

			 Paint paint = new Paint();
			Rect rect = new Rect(0, 0, finalBitmap.Width,
				finalBitmap.Height);

			paint.AntiAlias=true;
			paint.FilterBitmap=true;
			paint.Dither=true;
			canvas.DrawARGB(0, 0, 0, 0);
			paint.Color=Color.ParseColor("#BAB399");
			canvas.DrawCircle(finalBitmap.Width / 2 + 0.7f,
				finalBitmap.Height / 2 + 0.7f,
				finalBitmap.Width / 2 + 0.1f, paint);
			paint.SetXfermode(new PorterDuffXfermode(PorterDuff.Mode.SrcIn));
			canvas.DrawBitmap(finalBitmap, rect, rect, paint);

			return output;
		}	

        public void Run()
        {
            Rect dstRect = new Rect();
            long startTime = Java.Lang.System.NanoTime();
            while (running)
            {
                if (!holder.GetSurface().IsValid())
                    continue;


                float deltaTime = (Java.Lang.System.NanoTime() - startTime) / 10000000.000f;
                startTime = Java.Lang.System.NanoTime();

                if (deltaTime > 3.15)
                {
                    deltaTime = (float)3.15;
                }


                game.getCurrentScreen().update(deltaTime);
                game.getCurrentScreen().paint(deltaTime);



                Canvas canvas = holder.LockCanvas();
                canvas.GetClipBounds(dstRect);
                canvas.DrawBitmap(framebuffer, null, dstRect, null);
                holder.UnlockCanvasAndPost(canvas);


            }
        }

        /// <summary>
        ///   This method will determine the scaling ratio for the image view.
        /// </summary>
        /// <param name="startBounds">The visible rectangle of the thumbnail.</param>
        /// <param name="finalBounds">The visible rectangle of the expanded image view.</param>
        /// <returns></returns>
        private static float CalculateStartScale(Rect startBounds, Rect finalBounds)
        {
            float startScale;
            // First figure out width-to-height ratio of each rectangle.
            float finalBoundsRatio = finalBounds.Width() / (float)finalBounds.Height();
            float startBoundsRatio = startBounds.Width() / (float)startBounds.Height();

            if (finalBoundsRatio > startBoundsRatio)
            {
                // Extend start bounds horizontally
                startScale = (float)startBounds.Height() / finalBounds.Height();
                float startWidth = startScale * finalBounds.Width();
                float deltaWidth = (startWidth - startBounds.Width()) / 2;
                startBounds.Left -= (int)deltaWidth;
                startBounds.Right += (int)deltaWidth;
            }
            else
            {
                // Extend start bounds vertically
                startScale = (float)startBounds.Width() / finalBounds.Width();
                float startHeight = startScale * finalBounds.Height();
                float deltaHeight = (startHeight - startBounds.Height()) / 2;
                startBounds.Top -= (int)deltaHeight;
                startBounds.Bottom += (int)deltaHeight;
            }
            return startScale;
        }

        protected override void OnDraw(Canvas canvas)
        {
            base.OnDraw (canvas);

            var r = new Rect ();
            this.GetLocalVisibleRect (r);

            var half = r.Width() / 2;
            var height = r.Height();

            var percentage = (this.Limit - Math.Abs(this.CurrentValue)) / this.Limit;


            var paint = new Paint()
            {
                Color = this.CurrentValue < 0 ? this.negativeColor : this.positiveColor,
                StrokeWidth = 5
            };

            paint.SetStyle(Paint.Style.Fill);

            if (this.CurrentValue < 0)
            {
                var start = (float)percentage * half;
                var size = half - start;
                canvas.DrawRect (new Rect ((int)start, 0, (int)(start + size), height), paint);
            }
            else
            {
                canvas.DrawRect (new Rect((int)half, 0, (int)(half + percentage * half), height), paint);
            }
        }

 public override void GetItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state)
 {
     outRect.Left = left;
     outRect.Top = top;
     outRect.Right = right;
     outRect.Bottom = bottom;
 }

 protected override void OnFocusChanged(bool gainFocus, Android.Views.FocusSearchDirection direction, Rect previouslyFocusedRect)
 {
     if (gainFocus)
     {
         base.OnFocusChanged(true, direction, previouslyFocusedRect);
     }
 }

        static Bitmap GetCroppedBitmap (Bitmap bmp, int radius)
        {
            Bitmap sbmp;
            if (bmp.Width != radius || bmp.Height != radius)
                sbmp = Bitmap.CreateScaledBitmap (bmp, radius, radius, false);
            else
                sbmp = bmp;
            var output = Bitmap.CreateBitmap (sbmp.Width,
                             sbmp.Height, Bitmap.Config.Argb8888);
            var canvas = new Canvas (output);

            var paint = new Paint ();
            var rect = new Rect (0, 0, sbmp.Width, sbmp.Height);

            paint.AntiAlias = true;
            paint.FilterBitmap = true;
            paint.Dither = true;
            canvas.DrawARGB (0, 0, 0, 0);
            paint.Color = Color.ParseColor ("#BAB399");
            canvas.DrawCircle (sbmp.Width / 2 + 0.7f, sbmp.Height / 2 + 0.7f,
                sbmp.Width / 2 + 0.1f, paint);
            paint.SetXfermode (new PorterDuffXfermode (PorterDuff.Mode.SrcIn));
            canvas.DrawBitmap (sbmp, rect, rect, paint);

            return output;
        }

		// we need this constructor for LayoutInflater
		public LinedEditText (Context context, IAttributeSet attrs)
			: base (context, attrs)
		{
			rect = new Rect ();
			paint = new Paint ();
			paint.SetStyle (Android.Graphics.Paint.Style.Stroke);
			paint.Color = Color.LightGray;
		}

 public BitmapDrawable(Resources resources, int id, double left, double top, double right, double bottom)
 {
     mBitmap = BitmapFactory.DecodeResource(resources, id, new BitmapFactory.Options {
         InDither = false,
         InPreferredConfig = Bitmap.Config.Argb8888
     });
     mBounds = new Rect((int)left, (int)top, (int)right, (int)bottom);
 }

 /// <summary>
 /// Initializes a new instance of the <see cref="CanvasRenderContext" /> class.
 /// </summary>
 /// <param name="scale">The scale.</param>
 public CanvasRenderContext(double scale)
 {
     this.paint = new Paint();
     this.path = new Path();
     this.bounds = new Rect();
     this.pts = new List<float>();
     this.Scale = scale;
 }

		protected override void OnBoundsChange (Rect bounds)
		{
			base.OnBoundsChange (bounds);
			if (oval == null)
				return;
			
			oval.Set (0, 0, bounds.Width (), bounds.Height ());
		}