C#繪圖：帶背景，拖滑鼠畫矩形和直線

標籤：ogr   width   math   初始化   com   技術分享   實現   graph   click   

基於

Visual Studio 2012

.net framework 4.5

 

效果：

 代碼：

https://download.csdn.net/download/talkwah/10482880

 代碼預覽：

using System;using System.Drawing;using System.Windows.Forms;namespace WFA畫圖{    public partial class Form1 : Form    {        #region 成員變數        Point m_p1, m_p2;        bool m_flgKeuDowm = false;        Bitmap m_mapStart;        Bitmap m_mapEnd;        Bitmap m_mapInit;        Graphics m_graphics;        #endregion        public Form1()        {            InitializeComponent();            m_graphics = pictureBox1.CreateGraphics();                        // 最初的背景圖存起來，清除繪製圖形時用            m_mapInit = (Bitmap)pictureBox1.BackgroundImage;        }        #region 滑鼠事件        /// <summary>        /// 滑鼠按下        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void pictureBox1_MouseDown(object sender, MouseEventArgs e)        {            m_flgKeuDowm = true;            _initPoint(e);                    }                /// <summary>        /// 滑鼠移動        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void pictureBox1_MouseMove(object sender, MouseEventArgs e)        {            if (!m_flgKeuDowm)            {                return;            }            else            {                m_p2 = new Point(e.X, e.Y);            }            int width = Math.Abs(e.X - m_p1.X);            int height = Math.Abs(e.Y - m_p1.Y);            _draw();        }        /// <summary>        /// 滑鼠抬起        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private void pictureBox1_MouseUp(object sender, MouseEventArgs e)        {            m_flgKeuDowm = false;            // 最終的圖片設為背景圖            pictureBox1.BackgroundImage = m_mapEnd;            // 起止點初始化            _initPoint(e);        }        #endregion        private void _draw(){            // 每次的【終止圖】都是取自【起始圖】            m_mapEnd = (Bitmap)m_mapStart.Clone();            Graphics g = Graphics.FromImage(m_mapEnd);            Pen pen = new Pen(Color.Red,3);            if (rdoRect.Checked)            {                Point p1,p2;                _swapPoint(out p1,out p2 );                int width = Math.Abs(p2.X - p1.X);                int height = Math.Abs(p2.Y - p1.Y);                g.DrawRectangle(pen, p1.X, p1.Y, width, height);            }else if(rdoLine.Checked){                // 畫直線不用轉換點座標，直接用成員變數的Point                g.DrawLine(pen, m_p1, m_p2);            }            m_graphics.DrawImage(m_mapEnd, new Point(0, 0));        }        private void _initPoint(MouseEventArgs e)        {            m_p1 = new Point(e.X, e.Y);            m_p2 = m_p1;            if (pictureBox1.BackgroundImage != null)            {                m_mapStart = (Bitmap)pictureBox1.BackgroundImage;            }        }        private void _printPoint(Point p)        {            Console.WriteLine(p.X+","+p.Y);        }        private void _swapPoint(out Point _p1, out Point _p2)        {            //實現畫框隨意翻轉            _p1 = m_p1;            _p2 = m_p2;            if (m_p1.X > m_p2.X)            {                int tmp = _p1.X;                _p1.X = _p2.X;                _p2.X = tmp;            }            if (m_p1.Y > m_p2.Y)            {                int tmp = _p1.Y;                _p1.Y = _p2.Y;                _p2.Y = tmp;            }        }        #region 按鈕        private void btnClear_Click(object sender, EventArgs e)        {            pictureBox1.BackgroundImage = m_mapInit;        }        private void btnSave_Click(object sender, EventArgs e)        {            // 儲存            SaveFileDialog dlg = new SaveFileDialog();            dlg.DefaultExt = "png";            dlg.Filter = "Png Files|*.png";            dlg.FileName = "";            DialogResult dlgRet = dlg.ShowDialog();            if (dlgRet == DialogResult.OK)            {                pictureBox1.BackgroundImage.Save(dlg.FileName, System.Drawing.Imaging.ImageFormat.Png);            }        }        #endregion    }}

 

C#繪圖：帶背景，拖滑鼠畫矩形和直線