C#

Member 7921268 wrote:

Thanks in advance to those who want to give me a tip.

using System.Collections.Generic;
using System.Text;
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Imaging;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        bool flgDraw = false;

        Pen redPen;
        Pen blackPen1;
        Pen blackPen2;
        Pen orangePen;

        Bitmap drawing;
        GraphicsPath path = new GraphicsPath();

        private List<Point> polygonPoints = new List<Point>();

        public Form1()
        {
            InitializeComponent();

            redPen = new Pen(Color.Red, 2);
            blackPen1 = new Pen(Color.Black, 1);
            blackPen2 = new Pen(Color.Black, 2);
            orangePen = new Pen(Color.Orange, 1);

            panel1.MouseMove += new System.Windows.Forms.MouseEventHandler(this.panel1_MouseMove);
            panel1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.panel1_MouseDown);
            panel1.MouseUp += new System.Windows.Forms.MouseEventHandler(this.panel1_MouseUp);
            panel1.Paint += new System.Windows.Forms.PaintEventHandler(this.panel1_Paint);
            
            Shown += Form1_Shown;

            drawing = new Bitmap(panel1.Width, panel1.Height, panel1.CreateGraphics());
            Graphics.FromImage(drawing).Clear(Color.White);
        }

        private void Form1_Shown(Object sender, EventArgs e)
        {
            Grid(); // draw grid
        }

        private void panel1_MouseMove(object sender, MouseEventArgs e)
        {
            if (flgDraw)
            {
                Graphics Gpanel = Graphics.FromImage(drawing);
                panel1.CreateGraphics().DrawImageUnscaled(drawing, new Point(0, 0));
            }
        }

        private void panel1_MouseDown(object sender, MouseEventArgs e)
        {
            flgDraw = true;

            Graphics Gpanel = Graphics.FromImage(drawing);

            switch (e.Button)
            {
                // left button, add line to path
                case MouseButtons.Left:
                    polygonPoints.Add(new Point(e.X, e.Y));

                    if (polygonPoints.Count > 1)
                    {
                        path.AddLine(polygonPoints[polygonPoints.Count - 2], polygonPoints[polygonPoints.Count - 1]);
                        
                        // draw segment
                        Gpanel.DrawPath(redPen, path);
                    }
                    
                    break;

                // right button, redraw shape from path and fill it
                case MouseButtons.Right:
                    if (polygonPoints.Count > 2)
                    {
                        path.CloseAllFigures();

                        Gpanel.DrawPath(redPen, path);
                        Gpanel.FillPath(new SolidBrush(Color.Orange), path);
                    }
                    break;
            }
            
            panel1.CreateGraphics().DrawImageUnscaled(drawing, new Point(0, 0));
        }

        private void panel1_MouseUp(object sender, MouseEventArgs e)
        {
            flgDraw = false;
        }

        private void panel1_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.DrawImageUnscaled(drawing, new Point(0, 0));
        }

        // draw grid every 10 pixel
        private void Grid()
        {
            Graphics Gpanel = Graphics.FromImage(drawing);

            for (int i = 0; i < panel1.Width; i += 10)
                Gpanel.DrawLine(blackPen1, i, panel1.Height, i, 0);

            for (int i = 0; i < panel1.Height; i += 10)
                Gpanel.DrawLine(blackPen1, 0, i, panel1.Width, i);

            Gpanel.DrawLine(blackPen2, 0, panel1.Height - 90, panel1.Width, panel1.Height - 90);

            panel1.CreateGraphics().DrawImageUnscaled(drawing, new Point(0, 0));
        }

        // save image       
        private void btnSave_Click(object sender, EventArgs e)
        {
            drawing.Save("c:\\test.png", ImageFormat.Png);
        }
    }
}

Rob Philpott wrote:

If you run it, you'll find that the Select query(2nd) takes almost exactly twice as long as basic iteration (1st)

Rob Philpott wrote:

half the performance is a serious issue in a real-time system

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

Eddy Vluggen wrote:

One does not build real-time systems in a managed language

Rob Philpott wrote:

The JIT can optimise for the installed processor

Rob Philpott wrote:

the managed code was quicker)

Rob Philpott wrote:

And why not?

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

List<int> data = new List<int>();

for (int i = 0; i < 100; i++) data.Add(i);

Stopwatch sw = Stopwatch.StartNew();

int value = 1;

for (int i = 0; i < 99; i++)
{
 value *= data[i];
}

Console.WriteLine(";Simple Iteration time {0}", sw.Elapsed.TotalMilliseconds);

sw = Stopwatch.StartNew();

int linqAgg = data.Aggregate((first, second) =>; first * second);

Console.WriteLine("Linq Iteration time {0}", sw.Elapsed.TotalMilliseconds );
Console.ReadLine();

Quote:

LINQ-to-Objects generally is going to add some marginal overheads (multiple iterators, etc). It still has to do the loops, and has delegate invokes, and will generally have to do some extra dereferencing to get at captured variables etc. In most code this will be virtually undetectable, and more than afforded by the simpler to understand code.

var x = from g in numbers where g % 7 == 0 select g;
count = x.Count();

int Count = numbers.Count(p => p % 7 ==0);

• Release mode:
  
  • Simple Iteration : 2107
  • LINQ Query : 2168
  • Count Query : 2255
• Debug mode:
  
  • Simple Iteration : 2273
  • LINQ Query : 2281
  • Count Query : 2758

count = numbers.AsParallel().Count(g => g % 7 == 0);

• Simple Iteration : 2218
• PLINQ Query : 1749

Rob Philpott wrote:

half the performance is a serious issue in a real-time system

Rob Philpott wrote:

Because, unless I'm missing something