C# Graphics.Clear方法代码示例

        public override void Draw(System.Drawing.RectangleF dirtyRect)
        {
            var g = new Graphics();

            // NSView does not have a background color so we just use Clear to white here
            g.Clear(Color.White);

            //RectangleF ClientRectangle = this.Bounds;
            RectangleF ClientRectangle = dirtyRect;

            // Calculate the location and size of the drawing area
            // within which we want to draw the graphics:
            Rectangle rect = new Rectangle((int)ClientRectangle.X, (int)ClientRectangle.Y,
                                           (int)ClientRectangle.Width, (int)ClientRectangle.Height);
            drawingRectangle = new Rectangle(rect.Location, rect.Size);
            drawingRectangle.Inflate(-offset, -offset);
            //Draw ClientRectangle and drawingRectangle using Pen:
            g.DrawRectangle(Pens.Red, rect);
            g.DrawRectangle(Pens.Black, drawingRectangle);
            // Draw a line from point (3,2) to Point (6, 7)
            // using the Pen with a width of 3 pixels:
            Pen aPen = new Pen(Color.Green, 3);
            g.DrawLine(aPen, Point2D(new PointF(3, 2)),
                       Point2D(new PointF(6, 7)));

            g.PageUnit = GraphicsUnit.Inch;
            ClientRectangle = new RectangleF(0.5f,0.5f, 1.5f, 1.5f);
            aPen.Width = 1 / g.DpiX;
            g.DrawRectangle(aPen, ClientRectangle);

            aPen.Dispose();

            g.Dispose();
        }

        public RectangleTransparent()
        {
            clearPen = new Pen(Color.FromArgb(1, 0, 0, 0));
            borderDotPen = new Pen(Color.Black, 1);
            borderDotPen2 = new Pen(Color.White, 1);
            borderDotPen2.DashPattern = new float[] { 5, 5 };
            penTimer = Stopwatch.StartNew();
            ScreenRectangle = CaptureHelpers.GetScreenBounds();

            surface = new Bitmap(ScreenRectangle.Width, ScreenRectangle.Height);
            gSurface = Graphics.FromImage(surface);
            gSurface.InterpolationMode = InterpolationMode.NearestNeighbor;
            gSurface.SmoothingMode = SmoothingMode.HighSpeed;
            gSurface.CompositingMode = CompositingMode.SourceCopy;
            gSurface.CompositingQuality = CompositingQuality.HighSpeed;
            gSurface.Clear(Color.FromArgb(1, 0, 0, 0));

            StartPosition = FormStartPosition.Manual;
            Bounds = ScreenRectangle;
            Text = "ShareX - " + Resources.RectangleTransparent_RectangleTransparent_Rectangle_capture_transparent;

            Shown += RectangleLight_Shown;
            KeyUp += RectangleLight_KeyUp;
            MouseDown += RectangleLight_MouseDown;
            MouseUp += RectangleLight_MouseUp;

            using (MemoryStream cursorStream = new MemoryStream(Resources.Crosshair))
            {
                Cursor = new Cursor(cursorStream);
            }

            timer = new Timer { Interval = 10 };
            timer.Tick += timer_Tick;
            timer.Start();
        }

		private void EnsureTemporaryBitmap( int width, int height )
		{
			if( bmp != null )
			{
				if( bmp.Width >= width && bmp.Height >= height )
				{
					g.Clear( Color.Black );
					return;
				}

				width = Math.Max( width, bmp.Width );
				height = Math.Max( height, bmp.Height );
			}

			Helpers.DisposeAndClear( ref g );
			Helpers.DisposeAndClear( ref bmp );

			bmp = new Bitmap( width, height, PixelFormat.Format32bppRgb );

			g = Graphics.FromImage( bmp );
			
			g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
			g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
			g.TextRenderingHint = TextRenderingHint.AntiAliasGridFit;
			
			g.Clear( Color.Black );
		}

        public void DrawPieChart()
        {
            g = Graphics.FromImage(bitmapd);
            g.Clear(System.Drawing.Color.AliceBlue);
            int a = db.getCountFromDB("select count(*) from music");

            DataTable dt = db.getQueryFromDB("select distinct Genre from music");
            int index = 0;
            int[] myPiePercent = new int[dt.Rows.Count];
            string [] values=new string[dt.Rows.Count];
            foreach (DataRow r in dt.Rows)
            {
                string s = r[0].ToString();

                int b = db.getCountFromDB(string.Format("select count(*) from music where Genre='{0}'", s));
                myPiePercent[index] = (int)Math.Ceiling(((double)b * 100 / a));
                values[index] = s;
                index++;
            }

            System.Drawing.Color[] myPieColors = { c1, c2, c3, c4 };
            g.Clear(System.Drawing.Color.AliceBlue);
            System.Drawing.Size myPieSize ;
            System.Drawing.Point myPieLocation ;
            if (x < y)
            {
                myPieSize= new System.Drawing.Size(x - 50, x - 50);
                myPieLocation = new System.Drawing.Point(x / 2, x / 2);
            }
            else
            {
                myPieSize = new System.Drawing.Size(y - 50, y - 50);
                myPieLocation = new System.Drawing.Point(y / 2, y / 2);
            }
            int PiePercentTotal = 0;
            for (int PiePercents = 0; PiePercents < myPiePercent.Length; PiePercents++)
            {
                using (SolidBrush brush = new SolidBrush(myPieColors[PiePercents]))
                {
                    g.FillPie(brush, new System.Drawing.Rectangle(new System.Drawing.Point(10, 10), myPieSize), Convert.ToSingle(PiePercentTotal * 360 / 100), Convert.ToSingle(myPiePercent[PiePercents] * 360 / 100));
                }
                    PiePercentTotal += myPiePercent[PiePercents];
            }

            double xx = 0, yy = 0;
            for (int k = 0; k < index; k ++)
            {
                yy = Math.Sin(100*k*Math.PI/180) * 90;
                xx = Math.Cos(k*100 * Math.PI / 180) * 90;
                //g.DrawRectangle(new System.Drawing.Pen(System.Drawing.Color.Black), myPieLocation.X+(int)xx,myPieLocation.Y+ (int)yy, 5, 5);
                g.DrawString(values[k], new System.Drawing.Font("Sans", 10), System.Drawing.Brushes.Black, myPieLocation.X-30+(float)xx, myPieLocation.Y+(float)yy);
            }
        }

        public void Draw(Graphics g)
        {
            g.Clear(Color.Gray);

            PointF cellSize = new PointF((float)Size.X / (ChessGameField.FIELD_SIZE), (float)Size.Y / (ChessGameField.FIELD_SIZE));

            for (int i = 0; i <= ChessGameField.FIELD_SIZE; ++i)
            {
                g.DrawLine(Pens.Black, Pos.X + i * cellSize.X, Pos.Y, Pos.X + i * cellSize.X, Pos.Y + Size.Y);
            }

            for (int i = 0; i <= ChessGameField.FIELD_SIZE; ++i)
            {
                g.DrawLine(Pens.Black, Pos.X, Pos.Y + i * cellSize.Y, Pos.X + Size.X, Pos.Y + i * cellSize.Y);
            }

            Field.ForEachCell((pos, cell) => { if (cell.figure != null) cell.figure.Draw(g, GetColor(cell.figure.GetOwner()), GetCellPos(pos, cellSize), cellSize); return true; });

            if (State == ActionState.Selected)
            {
                PointF pos = GetCellPos(SelectedPoint, cellSize);
                Pen pen = new Pen(Brushes.Green, 2);
                int border = 4;
                g.DrawRectangle(pen, new Rectangle((int)pos.X + border + 1, (int)pos.Y + border + 1, (int)cellSize.X - border*2, (int)cellSize.Y - border*2));
            }
        }

        public void DrawPDF417(ref Graphics g)
        {
            g.Clear(this.backcolor);
            SolidBrush brush = new SolidBrush(this.forecolor);
            int x = this.leftmargin;
            int y = this.topmargin;
            SizeF ef = g.MeasureString(this.bottomcomment, this.txtFont, 0x7fffffff, StringFormat.GenericTypographic);
            for (int i = 0; i < this.encodebinarystr.Length; i++)
            {
                char ch = this.encodebinarystr[i];
                switch (ch)
                {
                    case '0':
                        x += this.modulewidth;
                        break;

                    case '1':
                        g.FillRectangle(brush, x, y, this.modulewidth, this.moduleheight);
                        x += this.modulewidth;
                        break;

                    default:
                        if (ch == 'Z')
                        {
                            y += this.moduleheight;
                            x = this.leftmargin;
                        }
                        break;
                }
            }
            g.DrawString(this.topcomment, this.txtFont, brush, (float) this.topcommentleftmargin, (float) this.topcommenttopmargin);
            //g.DrawString(" ", this.txtFont, brush, (float) 0f, (float) (this.symbolheight - ef.Height));
            brush.Dispose();
        }

        private void wypelniony()
        {
           
            bmp = new Bitmap((int)pbWIDTH, (int)pbHEIGHT);
            

            Point p1 = new Point((int)(pbWIDTH / 6), (int)(pbHEIGHT / 2));
            Point p2 = new Point((int)(pbWIDTH * 5 / 6), (int)(pbHEIGHT / 2));
            Point p1_25 = new Point(pbWIDTH / 3, pbHEIGHT / 4 * 3);
            Point p2_25 = new Point((int)(pbWIDTH / 3 * 2), (int)(pbHEIGHT / 4 * 3));
            Point p1_75 = new Point((int)(pbWIDTH / 3), (int)(pbHEIGHT / 4));
            Point p2_75 = new Point((int)(pbWIDTH / 3 * 2), (int)(pbHEIGHT / 4));
            Pen pen1 = new Pen(Brushes.Black, width_pen1);
            Pen pen2 = new Pen(Brushes.Black, width_pen2);

            

            g = Graphics.FromImage(bmp);
            g.Clear(Color.CornflowerBlue);
            g.FillRectangle(Brushes.White, new Rectangle(0, 0, pbWIDTH, pbHEIGHT - (int)(pbComplete * pbUnit)));
            g.DrawRectangle(pen1, 0, 0, pbWIDTH, pbHEIGHT);
            g.DrawLine(pen2, p1, p2);
            g.DrawLine(pen2, p1_25, p2_25);
            g.DrawLine(pen2, p1_75, p2_75);
            //g.DrawString(pbComplete + "%", new Font("Arial", pbHEIGHT / 5),Brushes.Black,new PointF(pbWIDTH/12,pbHEIGHT/4));
            this.Image = bmp;
            //return bmp;
        }

        public CDrawWinForm()
        {
            this.Icon = new System.Drawing.Icon(Path.Combine(System.Environment.CurrentDirectory, CSettings.sIcon));

            _Textures = new List<STexture>();
            _Bitmaps = new List<Bitmap>();

            _Keys = new CKeys();
            _Mouse = new CMouse();
            this.ClientSize = new Size(1280, 720);

            this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer | ControlStyles.Opaque, true);

            // Create the backbuffer
            _backbuffer = new Bitmap(CSettings.iRenderW, CSettings.iRenderH);
            _g = Graphics.FromImage(_backbuffer);
            _g.Clear(Color.DarkBlue);

            this.Paint += new PaintEventHandler(this.OnPaintEvent);
            this.Closing += new CancelEventHandler(this.OnClosingEvent);
            this.KeyDown += new KeyEventHandler(this.OnKeyDownEvent);
            this.KeyPress += new KeyPressEventHandler(this.OnKeyPressEvent);
            this.KeyUp += new KeyEventHandler(this.OnKeyUpEvent);
            this.Resize += new EventHandler(this.OnResizeEvent);

            this.MouseMove += new MouseEventHandler(this.OnMouseMove);
            this.MouseDown += new MouseEventHandler(this.OnMouseDown);
            this.MouseUp += new MouseEventHandler(this.OnMouseUp);

            FlipBuffer();
            Cursor.Show();
        }

        //Render a Drawing
        public static void Render(DnaDrawing drawing,Graphics g,int scale)
        {
            g.Clear(Tools.avgColour);

            foreach (DnaPolygon polygon in drawing.Polygons)
                Render(polygon, g, scale);
        }

 public IDisposable CreateContext()
 {
     _gfx = Graphics.FromImage(_bitmap);
     _gfx.Init();
     _gfx.Clear(System.Drawing.Color.Transparent);
     return _gfx;
 }

        //Render a Drawing
        public static void Render(DnaDrawing drawing,Graphics g,int scale)
        {
            g.Clear(Color.Black);

            foreach (DnaPolygon polygon in drawing.Polygons)
                Render(polygon, g, scale);
        }

 // ���»���
 public void PaintPalette(Graphics gp)
 {
     gp.Clear(this._bgColor);
     this._food.Paint(gp);
     foreach (Block b in this._blocks)
         b.Paint(gp);
 }

 void Former.new21file()
 {
     pixels = new PixelButton[64, 32];
     map = new Bitmap(64,32);
     gra = Graphics.FromImage(map);
     gra.Clear(Color.Transparent);
 }

        /// <summary>
        /// 压缩图片，返回map
        /// </summary>
        /// <param name="width">宽度</param>
        /// <param name="height">高度</param>
        /// <returns></returns>
        public Bitmap ResizeImg(int width, int height)
        {
            if (_oldImg == null)
                return null;
            int ow = _oldImg.Width, oh = _oldImg.Height; //原始大小
            if (height == -2)
            {
                var rale = (double)width / Math.Max(ow, oh); //压缩比例
                width = (int)Math.Ceiling(ow * rale);
                height = (int)Math.Ceiling(oh * rale);
            }
            else
            {
                width = (width != -1 ? width : ow);
                height = (height != -1 ? height : oh);
            }
            var bm = new Bitmap(width, height, PixelFormat.Format32bppRgb);

            _newGraphics = Graphics.FromImage(bm);
            //呈现质量
            _newGraphics.CompositingQuality = CompositingQuality.HighQuality;
            //像素偏移方式
            _newGraphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
            //平滑处理
            _newGraphics.SmoothingMode = SmoothingMode.HighQuality;
            //插补模式,双三次插值法
            _newGraphics.InterpolationMode = InterpolationMode.HighQualityBicubic;

            _newGraphics.Clear(Color.Transparent);

            _newGraphics.DrawImage(_oldImg, new Rectangle(0, 0, width, height), new Rectangle(0, 0, ow, oh),
                                  GraphicsUnit.Pixel);
            //return "处理成功";
            return bm;
        }

        public FormMain()
        {
            InitializeComponent();

            BGpath = currentDir + @"DATA\IMG\background.jpg";
            CHpath = currentDir + @"DATA\IMG\actor.png";

            btnSTART.Enabled = false;
            btnStep.Enabled = false;
            checkBG.Checked = checkCH.Checked = checkTXT.Checked = true;
            btnBackColor.BackColor = Color.White;
            btnForeColor.ForeColor = Color.White;
            btnBackColor.ForeColor = Color.Black;
            btnForeColor.BackColor = Color.Black;

            Label lab = new Label();
            lab.BackColor = Color.Transparent;
            ThumbPicCH.Controls.Add(lab);
            btnStep.Text = "��ʼ��������";

            GThumb = panel1.CreateGraphics();
            GThumb.Clear(Color.White);

            LoadFile();
        }