补充画圆画线

这是一个很简单的画图工具的例子
直接上图吧:
这里定义了线,矩形,椭圆等五种类型的外观,还有PEN,刷子,很简单的一个画图工具,希望能提起大家的兴趣
  private void Form1_Load(object sender,
                                System.EventArgs e)
        {
            // Get the full size of the form
            //取得窗口的完整大小
            fullSize = SystemInformation
                .PrimaryMonitorMaximizedWindowSize;

            //其实也即时初始化一副BMP图
            // Create a bitmap using full size
            bitmap = new Bitmap(fullSize.Width,
                                fullSize.Height);
            // Create a Graphics object from Bitmap
            //并由于创建一份GRAPHICS
            curGraphics = Graphics.FromImage(bitmap);
            // Set background color as form's color
            curGraphics.Clear(this.BackColor);
            // Create a new pen and brush as
            // default pen and brush
            curPen = new Pen(Color.Black);
            curBrush = new SolidBrush(Color.Black);
        }

在DOWN的时候,即取得开始的位置
        private void Form1_MouseDown(object sender,
                                     System.Windows.Forms.MouseEventArgs e)
        {
            // Store the starting point of
            // the rectangle and set the drag mode
            // to true
            curX = e.X;
            curY = e.Y;
            dragMode = true;
        }
每次移动,都是重新画,只是肉眼所不能分得清而已
        private void Form1_MouseMove(object sender,
                                     System.Windows.Forms.MouseEventArgs e)
        {
            // Find out the ending point of
            // the rectangle and calculate the
            // difference of starting and ending
            // points to find out the height and width
            // of the rectangle
            x = e.X;
            y = e.Y;
            diffX = e.X - curX;
            diffY = e.Y - curY;
            // If drag mode is true, call refresh
            // that forces window to repaint
            if (dragMode)
            {
//每次刷新其实都是调用ONPAINT函数
                this.Refresh();
            }
        }
在UP的时候,也画,并把标志量改为FALSE
   private void Form1_MouseUp(object sender,
                                   System.Windows.Forms.MouseEventArgs e)
        {
            diffX = x - curX;
            diffY = y - curY;
            //这里下一个留个问题?SWITCH是OO被人痛批的,可这里如果不采用SWITCH,有什么好的办法呢!
            switch (drawIndex)
            {
                    //不管是矩形或者是椭圆形,都是取X,Y,差值就可以了
                case 1:
                    {
                        // Draw a line
                        curGraphics.DrawLine(curPen,
                                             curX, curY, x, y);
                        break;
                    }
                case 2:
                    {
                        // Draw an ellipse
                        curGraphics.DrawEllipse(curPen,
                                                curX, curY, diffX, diffY);
                        break;
                    }
                case 3:
                    {
                        // Draw rectangle
                        curGraphics.DrawRectangle(curPen,
                                                  curX, curY, diffX, diffY);
                        break;
                    }
                case 4:
                    {
                        // Fill rectangle
                        curGraphics.FillRectangle(curBrush,
                                                  curX, curY, diffX, diffY);
                        break;
                    }
                case 5:
                    {
                        // Fill ellipse
                        curGraphics.FillEllipse(curBrush,
                                                curX, curY, diffX, diffY);
                        break;
                    }
            }
            // Refresh
            RefreshFormBackground();
            // Set drag mode to false
            dragMode = false;
        }

定义每次点击样式BUTTON的值,其实应该定一个枚举才对
   private void LineDraw_Click(object sender,
                                    System.EventArgs e)
        {
            drawIndex = 1;
        }

     private void RefreshFormBackground()
        {
            //将原来的保存起来,作为背景图像
            curBitmap = bitmap.Clone(
                new Rectangle(0, 0, this.Width, this.Height),
                bitmap.PixelFormat);
            this.BackgroundImage = curBitmap;
        }
//GDI一直强调的一个模式吧
        private void Form1_Closed(object sender,
                                  System.EventArgs e)
        {
            // Dispose all public objects
            curPen.Dispose();
            curBrush.Dispose();
            curGraphics.Dispose();
        }

        private void SaveBtn_Click(object sender,
                                   System.EventArgs e)
        {
            // Save file dialog
            SaveFileDialog saveFileDlg = new SaveFileDialog();
            saveFileDlg.Filter =
                "Image files (*.bmp)|*.bmp|All files (*.*)|*.*";
            if (saveFileDlg.ShowDialog() == DialogResult.OK)
            {
                // Create bitmap and call Save method
                // to save it
                Bitmap tmpBitmap = bitmap.Clone
                    (new Rectangle(0, 0,
                                   this.Width, this.Height),
                     bitmap.PixelFormat);
                tmpBitmap.Save(saveFileDlg.FileName,
                               ImageFormat.Bmp);
            }
        }
剩下一个ONPAINT,和前面差不多,这里就略了
这是网上一个例子的代码,比较有趣贴近生活,但作者原来的代码里出现了好多重复,还有一些硬编码的,就不完全贴出了
,只当给大家一个兴趣,GDI其实能完成很多事的哦

还有一个是画饼图的,其实也是画圆啦
    Graphics g = this.CreateGraphics();
            g.Clear(this.BackColor);
            Rectangle rect = new Rectangle(350, 150, 200, 200);
            float angle = 0;
            float sweep = 0;         
            foreach(sliceData dt in sliceList)
            {
百分比值*360
                sweep = 360f * dt.share / shareTotal;
画扇形部分,范围即矩形内,
                if(flMode)
                    g.FillPie(new SolidBrush(dt.clr), rect, angle, sweep);
                else
                    g.DrawPie(new Pen(dt.clr), rect, angle, sweep);
                angle += sweep;
            }
            g.Dispose();

一个画线,一个填充




到具体的工程里可能还要写一些百分比,具体数目之类的,但有了前面的基础,大家应该都知道很简单的吧!就略啦!

下星期看到好玩的例子再贴!嘿嘿!加油