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Mendelbrot Calculation Code Keeps Returning 2 for IterationCount

I'm working on writing a Mendelbrot renderer in C# to practice multithreading, but am having an issue where my calculation code maxes out at 2 iterations. I don't really understand why since the online references I've been looking at seem to calculate it the same way as me. No matter what coordinates of pixels I provide, it always returns 2 (aside from 0,0 and 0,1).
`
using System;
using System.Numerics;
using SkiaSharp;
namespace Mandelbrot
{
internal class Program
{
const int MaxIterations = 100;
static void Main(string[] args)
{
int size = 250;
int[,] grid = Run(size, 0, 0, 1);
// Console.WriteLine("Please specify a square size for the image.");
// try
// {
// Console.Write("Length: ");
// height = Int32.Parse(Console.ReadLine());
// }
// catch (FormatException e)
// {
// Console.WriteLine(e);
// throw;
// }
using (var surface = SKSurface.Create(width: size, height: size, SKColorType.Rgba8888, SKAlphaType.Premul))
{
SKCanvas canvas = surface.Canvas;
canvas.DrawColor(SKColors.Coral);
for (int i = 0; i < grid.GetLength(0); i++)
{
for (int j = 0; j < grid.GetLength(1); j++)
{
if (grid[i, j] >= MaxIterations)
canvas.DrawPoint(new SKPoint(i, j), SKColors.Black);
}
}
canvas.DrawPoint(new SKPoint(250, 250), SKColors.Chartreuse);
OutputImage(surface);
}
Console.WriteLine("Program successfully completed.");
}
public static int[,] Run(int size, int fromX, int fromY, int h)
{
int[] oulltput = new int[size * size];
int[,] output = new int[size, size];
for (int i = 0; i < output.GetLength(0); i += 1)
{
for (int j = 0; j < output.GetLength(1); j += 1)
{
float x = fromX + i * h;
float y = fromY + j * h;
output[i, j] = IterCount(x, y, MaxIterations);
}
}
return output;
}
public static int IterCount(float constX, float constY, int maxIterations)
{
const float maxMagnitude = 2f;
const float maxMagnitudeSquared = maxMagnitude * maxMagnitude;
int i = 0;
float x = 0.0f, y = 0.0f;
float xSquared = 0.0f, ySquared = 0.0f;
while (xSquared + ySquared <= maxMagnitudeSquared && i < maxIterations)
{
xSquared = x * x;
ySquared = y * y;
float xtmp = xSquared - ySquared + constX;
y = 2.0f * x * y + constY;
x = xtmp;
i++;
}
return i;
}
private static void OutputImage(SKSurface surface)
{
Console.WriteLine("Attempting to write .png to disk...");
using (var image = surface.Snapshot())
using (var data = image.Encode(SKEncodedImageFormat.Png, 80))
using (var stream = File.OpenWrite("out.png"))
{
// save the data to a stream
data.SaveTo(stream);
Console.WriteLine("Success!");
}
}
}
}
`
I tried to use breakpoints and writeline statements to debug but I can't figure out where my math is going wrong. I keep getting 2 for my iteration count.

On a canvas, how do I let the user to only draw a circle in a specified line?

Im doing school project. My task is to write a small Winform application that represents the Bezier Curve, but with some constraints.
I did almost everything, just one more step is ahead of me.
The whole program starts with an empty canvas, then the user can click on it, and a circle is drawn. After every 4th click, the bezier curve appears to that polygon. Now comes my problem.
What I am stuck with is that I have to controll somehow where the 5th click is going to be. It must be on a line that comes from 2 points: the 3rd and 4th points.
Can anybody help me with this? I have really no idea how to even start.
So far, this is my code.
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace grafika_beadando_kettesert
{
public partial class MainForm : Form
{
Graphics g;
int counter = 0;
Pen PenBlack = Pens.Black; //ezzel a tollal rajzolom a vonalat
Pen PenCurve = new Pen(Color.Blue, 3f); //ezzel a tollal rajzolom a görbét
Brush PenPoint; //Ezzel töltöm ki a pontot
int size = 4; // a lerakott pont mérete
int found = -1;
List<PointF> Points = new List<PointF>(); //ebbe a listába tárolom a pontokat
PointF p0, p1;
public MainForm()
{
InitializeComponent();
PenPoint = new SolidBrush(canvas.BackColor);
this.DoubleBuffered = true;
}
private void canvas_Paint(object sender, PaintEventArgs e)
{
g = e.Graphics;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
for (int i = 0; i < Points.Count - 1; i++) // mindig meg kell rajzolni az eddig meghúzott vonalakat a polygonból újra
g.DrawLine(PenBlack, Points[i], Points[i + 1]);
if (counter == 4)
{
DrawBeziergorbe();
counter = 0;
}
for (int i = 0; i < Points.Count; i++) // ezzel rajzolom meg az eddig felrakott pontokat újra
{
g.FillEllipse(PenPoint, Points[i].X - size, Points[i].Y - size, 2 * size, 2 * size);
g.DrawEllipse(PenBlack, Points[i].X - size, Points[i].Y - size, 2 * size, 2 * size);
}
}
private void canvas_MouseUp(object sender, MouseEventArgs e)
{
found = -1;
}
private void canvas_MouseMove(object sender, MouseEventArgs e)
{
if (found != -1)
{
Points[found] = e.Location;
canvas.Invalidate();
}
}
private void canvas_MouseDown(object sender, MouseEventArgs e)
{
for (int i = 0; i < Points.Count; i++)
{
if (Math.Abs(Points[i].X - e.X) <= size && Math.Abs(Points[i].Y - e.Y) <= size)
{
found = i;
break;
}
}
if (found == -1)
{
Points.Add(e.Location); //ha nincs túl közel a lerakott pont egy jelenlegihez, akkor hozzáadja a
//"Points" listához, hogy innen kiolvasva újra belehessen rajzolni
found = Points.Count - 1;
counter++;
canvas.Invalidate();
}
}
private void DrawBeziergorbe() //Mivel n-ed fokú bezier görbe kell, ezért használom a binomiálisos megoldást
{
int n = Points.Count - 1;
double t = 0;
double h = 1.0 / 500.0;
double b = 0.0;
p0 = new PointF(0, 0);
for (int i = 0; i <= n; i++)
{
b = B(n, i, t);
p0.X += (float)(b * Points[i].X);
p0.Y += (float)(b * Points[i].Y);
}
while (t < 1)
{
t += h;
p1 = new PointF(0, 0);
for (int i = 0; i <= n; i++)
{
b = B(n, i, t);
p1.X += (float)(b * Points[i].X);
p1.Y += (float)(b * Points[i].Y);
}
g.DrawLine(PenCurve, p0, p1);
p0 = p1;
}
}
private double B(int n, int i, double t)
{
return Binom(n, i) * (Math.Pow(1 - t, n - i) * Math.Pow(t, i));
}
private uint Binom(int n, int k)
{
if (n == 0) return 0;
else if (k == 0 || k == n) return 1;
else return Binom(n - 1, k - 1) + Binom(n - 1, k);
}
}
}

You can simply project the click position on the desired line.
If c is the click position and A and B are the two last control points, then the projected position p is:
d = B - A
p = A + dot(c - A, d) / dot(d, d) * d

Massive for loop on a image file, frames dipping around 7 fps, I need that to be higher

I am currently trying new techniques for going through every pixel on a image and doing some minor process for each. Here is my active code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
namespace ImageProcessingExmp1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
Timer timer = new Timer();
private void Form1_Load(object sender, EventArgs e)
{
timer.Tick += ChangeColor;
timer.Interval = 1;
timer.Start();
pictureBox1.Width = this.Width;
pictureBox1.Height = this.Height;
pictureBox1.Left = 0;
pictureBox1.Top = 0;
this.WindowState = FormWindowState.Maximized;
}
int timerinc = 0;
public void ChangeColor(object sender, EventArgs e)
{
if (timerinc>=240)
{
timer.Stop();
}
timerinc+=10;
Bitmap bmp = (Bitmap)new Bitmap(this.Width,this.Height);
Benchmark.Start();
///////////////////////////////////////////////////////////////////////////////
// Get the area to be painted
Rectangle areaToPaint = new Rectangle();
BitmapData data = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
int stride = data.Stride;
Random rnd = new Random(DateTime.Now.Millisecond);
unsafe
{
byte* ptr = (byte*)data.Scan0;
// Check this is not a null area
// Go through the draw area and set the pixels as they should be
for (int y = 0; y < bmp.Height; y++)
{
for (int x = 0; x < bmp.Width; x++)
{
// layer.GetBitmap().SetPixel(x, y, m_colour);
byte x2 = Convert.ToByte(x > 255 ? 0 : x);
byte y2 = Convert.ToByte(y > 255 ? 0 : y);
ptr[(x * 3) + y * stride] = x2;
ptr[(x * 3) + y * stride + 1] = y2;
ptr[(x * 3) + y * stride + 2] = 255;
}
}
}
bmp.UnlockBits(data);
/////////////////////////////////////////////////////////////////////////////////
Benchmark.End();
double seconds = Benchmark.GetSeconds();
//MessageBox.Show(seconds.ToString());
richTextBox1.Text += seconds.ToString()+'\n' ;
richTextBox2.Text += DateTime.Now.Second.ToString()+'\n';
pictureBox1.Image= bmp;
String[] lines = richTextBox1.Text.Split('\n');
double avg = 0;
double sum = 0;
double num = 0;
foreach (var line in lines)
{
// MessageBox.Show(line);
double tet = 0;
Double.TryParse(line, out tet);
sum += tet;
num++;
}
avg = sum / num;
label1.Text = "fps = " + (1/avg).ToString();
}
public class Benchmark
{
private static DateTime startDate = DateTime.MinValue;
private static DateTime endDate = DateTime.MinValue;
public static TimeSpan Span { get { return endDate.Subtract(startDate); } }
public static void Start() { startDate = DateTime.Now; }
public static void End() { endDate = DateTime.Now; }
public static double GetSeconds()
{
if (endDate == DateTime.MinValue) return 0.0;
else return Span.TotalSeconds;
}
}
}
}
I need to get the FPS to around, say, 90 fps. How can I do this? Do I need to use something other than C#? The current fps is about 7.
EDIT 1
Stack overflow edited out some of my text.. weird...
Here is the real unsafe code.
unsafe
{
byte* ptr = (byte*)data.Scan0;
// Check this is not a null area
// Go through the draw area and set the pixels as they should be
for (int y = 0; y< bmp.Height; y++)
{
for (int x = 0; x < bmp.Width; x++)
{
// layer.GetBitmap().SetPixel(x, y, m_colour);
byte x2 = Convert.ToByte(x > 255 ? 0 : x);
byte y2 = Convert.ToByte(y > 255 ? 0 : y);
ptr[(x * 3) + y * stride] = x2;
ptr[(x * 3) + y * stride + 1] = y2;
ptr[(x * 3) + y * stride + 2] = 255;
}
}
}
Edit 2
Wow... it did it again... I am replacing the less than symbols with (LESSTHAN)
unsafe
{
byte* ptr = (byte*)data.Scan0;
// Check this is not a null area
// Go through the draw area and set the pixels as they should be
for (int y = 0; y < bmp.Height; y++)
{
for (int x = 0; x < bmp.Width; x++)
{
// layer.GetBitmap().SetPixel(x, y, m_colour);
byte x2 = Convert.ToByte(x > 255 ? 0 : x);
byte y2 = Convert.ToByte(y > 255 ? 0 : y);
ptr[(x * 3) + y * stride] = x2;
ptr[(x * 3) + y * stride + 1] = y2;
ptr[(x * 3) + y * stride + 2] = 255;
}
}
}
Edit 3
Tried changing the format to PixelFormat.Format32bppPArgb. Didn't work. Got this:
Click to view image
Edit 4
Plenty of changes to the code. Here is the current code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
namespace ImageProcessingExmp1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
Timer timer = new Timer();
private void Form1_Load(object sender, EventArgs e)
{
timer.Tick += ChangeColor;
timer.Interval = 1;
timer.Start();
pictureBox1.Width = this.Width;
pictureBox1.Height = this.Height;
pictureBox1.Left = 0;
pictureBox1.Top = 0;
this.WindowState = FormWindowState.Maximized;
bmp=(Bitmap)new Bitmap(this.Width, this.Height);
}
int timerinc = 0;
int stride;
Bitmap bmp;
BitmapData data;
public void ChangeColor(object sender, EventArgs e)
{
timerinc+=10;
Benchmark.Start();
///////////////////////////////////////////////////////////////////////////////
data= bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
stride = data.Stride;
unsafe
{
byte* ptr = (byte*)data.Scan0;
// Check this is not a null area
// Go through the draw area and set the pixels as they should be
for (int y = 0; y < bmp.Height; y++)
{
int yTimeStride = y * stride;
byte y2 = (byte)(y > 255 ? 0 : y);
for (int x = 0; x < bmp.Width; x++)
{
int addressToAssign = (x * 3) + yTimeStride;
byte x2 = (byte)(x > 255 ? 0 : x);
ptr[addressToAssign] = x2;
ptr[addressToAssign + 1] = y2;
ptr[addressToAssign + 2] = x2;
}
}
}
bmp.UnlockBits(data);
/////////////////////////////////////////////////////////////////////////////////
Benchmark.End();
double seconds = Benchmark.GetSeconds();
//MessageBox.Show(seconds.ToString());
richTextBox1.Text += seconds.ToString()+'\n' ;
richTextBox2.Text += DateTime.Now.Second.ToString()+'\n';
pictureBox1.Image= bmp;
String[] lines = richTextBox1.Text.Split('\n');
double avg = 0;
double sum = 0;
double num = 0;
foreach (var line in lines)
{
// MessageBox.Show(line);
double tet = 0;
Double.TryParse(line, out tet);
sum += tet;
num++;
}
avg = sum / num;
label1.Text = "fps = " + (1/avg).ToString();
tst1.Add(1/avg*20);
if (timerinc >= 500)
{
timer.Stop();
Bitmap bmp2 = new Bitmap(pictureBox2.Width,pictureBox2.Height);
data = bmp2.LockBits(new Rectangle(0, 0, bmp2.Width, bmp2.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
stride = data.Stride;
unsafe
{
byte* ptr = (byte*)data.Scan0;
// Check this is not a null area
// Go through the draw area and set the pixels as they should be
for (int x = 0; x < tst1.Count; x++)
{
for (int y = 0; y < (int)tst1[x]; y++)
{
//MessageBox.Show(x.ToString());
if (y<bmp2.Height)
{
ptr[(x * 3) + (int)y * stride] = 255;//b
ptr[(x * 3) + (int)y * stride + 1] =0;//g
ptr[(x * 3) + (int)y * stride + 2] = 255;//r
}
}
}
}
bmp2.UnlockBits(data);
pictureBox2.Image = bmp2;
}
}
public List<double> tst1 = new List<double>();
public class Benchmark
{
private static DateTime startDate = DateTime.MinValue;
private static DateTime endDate = DateTime.MinValue;
public static TimeSpan Span { get { return endDate.Subtract(startDate); } }
public static void Start() { startDate = DateTime.Now; }
public static void End() { endDate = DateTime.Now; }
public static double GetSeconds()
{
if (endDate == DateTime.MinValue) return 0.0;
else return Span.TotalSeconds;
}
}
}
}
Unfortunately, this only gets me 5 fps. I am starting to believe that painting on a bitmap then putting it onto the screen is not the way to quickly render games. Does anybody know another way?

Considering the code you're benchmarking:
rnd is useless (wrong copy/paste?)
you're doing way too much multiplication, consider using:
Code:
for (int y = 0; y < bmp.Height; y++)
{
int yTimeStride = y * stride;
byte y2 = Convert.ToByte(y > 255 ? 0 : y);
for (int x = 0; x < bmp.Width; x++)
{
int addressToAssign = (x * 3) + yTimeStride;
byte x2 = Convert.ToByte(x > 255 ? 0 : x);
ptr[addressToAssign] = x2;
ptr[addressToAssign + 1] = y2;
ptr[addressToAssign + 2] = 255;
}
}
This will reduce multiplication with y from Height*Width*3 to Height and reduce multiplication with x by 3.

Execution of OnPaintBackground Many times C#?

I have created a UserControl that split the screen into rectangles but my control is executing the OnPaintBackground Many times whilst it should execut it just one please help me because it's really important to execut it just once because the scrren starts flickaring much.
public partial class Schedual : UserControl
{
int days;
public int Days
{
get { return days; }
set
{
days = value;
change = true;
Invalidate(true);
}
}
int periods;
public int Periods
{
get { return periods; }
set
{
periods = value;
change = true;
Invalidate(true);
}
}
Brush brush;
bool change = false;
List<Panel> panels;
public Schedual()
{
InitializeComponent();
this.ResumeLayout(true);
this.days = 1;
this.periods = 1;
brush = Brushes.White;
change = false;
}
protected override void OnPaint(PaintEventArgs e)
{
//stuff ....... or base.OnPaint(e);
}
protected override void OnPaintBackground(PaintEventArgs e)
{
Graphics g = e.Graphics;
var h = this.Height / days;
var w = this.Width / periods;
for (int i = 0; i < days; i++)
{
for (int j = 0; j <= periods; j++)
{
g.FillRectangle(brush, j * w, i * h, w, h);
if (change)
{
AddPanel(j * w, i * h, w, h);
}
g.DrawLine(Pens.Black, 0, i * h, this.Right, i * h); //draw the horizantle lines
g.DrawLine(Pens.Black, j * w, 0, this.Bottom, j * w); //draw the verical lines
}
}
change = false;
}
}
the output is that the screen is flickaring much when drawing the background over and over again ......

Double buffering...
See more info here - http://msdn.microsoft.com/en-us/library/3t7htc9c.aspx

Increase bar chart values with button clicks

I am trying to create a graph that will show the progress of a workout. Every five button clicks a tick should be added to the graph. This is a example of how it should look.
For demonstration purposes I am using a button click, In production the clicks will be every twenty revolutions of a wheel.
private int counter = 0;
private void button1_Click(object sender, EventArgs e)
{
counter++;
// code will go here
}
Thanks in advance

You can use either a Bitmap Buffer or a panel to draw on. Here is a headstart: Just a sample.
reference.
This solution is based on WinForms & Panel_Paint(). You may try to add vertical Progress Label and Chart's Y Axis value labeling.
Code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1(){
InitializeComponent();
}
private int counter = 0;
private int px = 10;
private int py = 180;
private int total5Clicks = 0;
private void button1_Click(object sender, EventArgs e)
{
counter++;
label1.Text = "Total Clicks = " + counter.ToString();
if (Math.Abs(counter % 5) == 0){
if (Math.Abs(counter / 5) > 0){
total5Clicks = total5Clicks + 1;
PaintOnChartPanel(total5Clicks);}
}
}
private void panel1_Paint(object sender, PaintEventArgs e){
}
private void PaintOnChartPanel(int total5Times)
{
//Add a new Panel Paint EventHandler
panel1.Paint += new PaintEventHandler(panel1_Paint);
using (Graphics g = this.panel1.CreateGraphics())
{
Brush brush = new SolidBrush(Color.Green);
g.FillRectangle(brush, px, py, 20, 20);
Pen pen = new Pen(new SolidBrush(Color.White));
g.DrawRectangle(pen, px, py, 20, 20);
//add each total5Click into chart block
g.DrawString((total5Times).ToString(), new Font("Arial", 7),
new SolidBrush(Color.AntiqueWhite),
px + 1, py+8, StringFormat.GenericDefault);
pen.Dispose();}
if (py > 20){
py = py - 20;}
else{
MessageBox.Show("Reached Top of the Panel");
if (px < 200){
px = px + 20;
py = 180;}
else{
MessageBox.Show("Reached Right of the Panel");
}
}
}
}
}
Output Form:

You can determine if you have a multiple of five with
bool drawTickMark = clicks % 5 == 0;
% is the modulo operator which returns the remainder of an integer division. E.g. 13 % 5 = 3 and 13 / 5 = 2 because 2 * 5 + 3 = 13.
clicks % 5 will be zero for clicks = 0, 5, 10, 15, ...

I'm not much of an ASP.NET guy but here's an algorithm you can use to draw the squares
int perColumn = Height / squareSize;
int totalColumns = (squareCount / perColumn) + 1;
for (int y = 0; y <= totalColumns - 1; y++)
{
int itemCount = squareCount - (y * perColumn);
if (itemCount > perColumn)
itemCount = perColumn;
for (int x = 0; x <= itemCount - 1; x++)
e.Graphics.FillRectangle(RandomBrush, New Rectangle((column * SquareSize) + 3, (i * SquareSize) + 3, SquareSize - 2, SquareSize - 2))
public sealed class ClickGraph : Control
{
private int squareCount = 1;
public int SquareCount
{
get
{
return squareCount;
}
set
{
squareCount = value;
Invalidate();
}
}
private int squareSize = 25;
public int SquareSize
{
get
{
return squareSize;
}
set
{
squareSize = value;
Invalidate();
}
}
public ClickGraph()
{
SetStyle(ControlStyles.ResizeRedraw, true);
}
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.Clear(BackColor);
int perColumn = Height / squareSize;
int totalColumns = (squareCount / perColumn) + 1;
for (int y = 0; y <= totalColumns - 1; y++)
{
int itemCount = squareCount - (y * perColumn);
if (itemCount > perColumn)
itemCount = perColumn;
for (int x = 0; x <= itemCount - 1; x++)
e.Graphics.FillRectangle(RandomBrush, New Rectangle((column * SquareSize) + 3, (i * SquareSize) + 3, SquareSize - 2, SquareSize - 2))
}
}
}