John Roach » Coding for fun

How to add images to DataGridView cell using C# and Windows Forms

John Roach — Fri, 13 Jan 2012 14:14:02 +0000

There are many ways to skin this old cat. When choosing the way, you must first decide when should the adding of images take place. I chose to add images during sorting.

Let us assume you already added some data to gridview via datatable using ;

   1: dataGridView1.DataSource = siparis_tablo_guncel;

So now you know we have a filled up dataGridView.

Now let us assume in the dataGridView1 we want to add images according to the data within the 6th column. So what we first need to do is to create an image column by writing;

DataGridViewImageColumn img = new DataGridViewImageColumn();
  
img.Name = "img";
img.HeaderText = "Image Column";
img.ValuesAreIcons = true;
  
dataGridView1.Columns.Add(img);

Now we have a image column. With the name “img” with the header “Image Column” As you can see in the 5th line I have stated that my images are actually icons. The reason I did this was that I found out that icons take up less space and flickers less. You can if you want change this option as you see fit.

Now let us get cracking and add those images according to the columns;

int number_of_rows = dataGridView1.RowCount;
for (int i = 0; i < number_of_rows; i++)
{
    if (dataGridView1.Rows[i].Cells[6].Value.ToString() == "true")
    {
        Icon image = SUT.Properties.Resources.succcess_icon;
        dataGridView1.Rows[i].Cells["img"].Value = image;
    }
    else
    {
        Icon image = SUT.Properties.Resources.cancel_icon;
        dataGridView1.Rows[i].Cells["img"].Value = image;
    }
}

I hope this has been informative. Please do tell if you see any mistakes and wish to make suggestions.

Have fun!

Installing node.js 0.6.2 on Fedora 16

John Roach — Sun, 20 Nov 2011 12:07:28 +0000

Image via Wikipedia

This one was a little hard. I got lots of help so I decided to post it online since it doesn’t exist on the internet yet… I wonder why….

The simple step by step instruction:

sudo yum install git

git clone --depth 1 git://github.com/joyent/node.git

cd node
git checkout v0.6.2
sudo yum install openssl-devel
sudo yum install gcc # you can skip this if you already have gcc
sudo yum install gcc-c++ # you can skip this if you already have gcc-c++
./configure [ thank you Ed for the heads up! ]
make -j2
make install
export PATH=$PATH:/usr/local/bin:/usr/local #this is to add usr local to your path wher nodejs was installed
sudo visudo
Find Defaults secure_path=/sbin:/bin:/usr/sbin:/usr/bin
go to the end “a” for append, type “:/usr/local/bin”, ESC, “:wq”
curl http://npmjs.org/install.sh |sudo sh #installing npm a very good too to install nodejs packages
sudo yum install mongodb #installing mongodb
#go to the dir where you wish to code and use npm!!
npm install mongodb
npm install mongoose
npm install express
npm install coffee-script
npm install stylus
npm install underscore
npm list
/home/john/someproject
├── coffee-script@1.1.3
├─┬ express@2.5.1
│ ├─┬ connect@1.8.0
│ │ └── formidable@1.0.7
│ ├── mime@1.2.4
│ ├── mkdirp@0.0.7
│ └── qs@0.3.2
├── mongodb@0.9.7-0
├─┬ mongoose@2.3.13
│ ├── colors@0.5.1
│ ├── hooks@0.1.9
│ └── mongodb@0.9.6-23
├─┬ stylus@0.19.3
│ ├── cssom@0.2.0
│ ├── growl@1.1.0
│ └── mkdirp@0.0.7
└── underscore@1.2.2

Blinking lights MSP430 FG461x

John Roach — Sat, 14 May 2011 15:16:23 +0000

Image via Wikipedia

I have been working on MSP430 for sometime now. It is an TI (Texas Instruments ) chip. Very fun to play with. We are using a MSP430FG461x series experimental board. This little experimental board has all the bells and whistles one may need to create any application from a home automation controller to a simple step-motor driver. TI provides very good documentation for this grown up toy.

Our first lab homework for this baby was :

By using the MSP430 FG4618 Microcontroller, write a program that controls the LED #1, #2,#4.When we perpetually push the two buttons at the right bottom corner of the board, all ofthe LEDs turn on.When we push perpetually one of the buttons, only the LED #4 blinks, the others turn off.When we push no buttons, the LED #1 and #2 blinks complementarily and the LED#4 turnsoff.

My biggest problem with this exercise was to find what led was connected to what port. However in the end I figured it all out.

Below you will find the program :

#include 

void initPortPins(void);

void main(void)
{
	 WDTCTL=WDTPW + WDTHOLD;
	 initPortPins();
	 while(1) {
	 	if (P1IN == (0x00))
	 	{
			P2OUT |= 0x06;
			P5OUT |= 0x02;
		}
		else if (P1IN == 0x03)
		{
			P2OUT &= 0x00;
			P5OUT &= 0x00;
			P2OUT |= 0x02;
			__delay_cycles (40000);
			P2OUT &= 0x00;
			P2OUT |= 0x04;
			__delay_cycles (40000);
		}
		else
		{
			P2OUT &= 0x00;
			P5OUT &= 0x00;
			__delay_cycles (40000);
			P5OUT |= 0x02;
			__delay_cycles (40000);
		}
	 }
};

void initPortPins(void)
{
  P1DIR = 0x00;	// Set P2.2,1 as outputs
  P5DIR = 0x02; // Set P5.1 as output
  P2DIR = 0x06; // Set P2.1 to 1
};

Installing node.js and npm to a Fedora 14 PC

John Roach — Wed, 16 Mar 2011 18:02:05 +0000

Hi! Below is the step by step instructions to install the following in a Fedora 14 PC; ( no sudo yum install shortcut )

+ nodejs

+ npm

+ mongo database

node components

+ mongoose

+ express

+ coffeescript

+ stylus

+ underscore

Step1. Install nodejs : First download the latest nodejs and un-tar it. Than;

export JOBS=2 # optional, sets number of parallel commands.
./configure
make
make install

Step 2. Install npm :

sudo ln -s /usr/local/bin/node /usr/bin/node
sudo ln -s /usr/local/lib/node /usr/lib/node
sudo ln -s /usr/local/bin/npm /usr/bin/npm
sudo ln -s /usr/local/bin/node-waf /usr/bin/node-waf
git clone http://github.com/isaacs/npm.git
cd npm
sudo make install

Step 3. So now you have npm and nodejs. The next step is to install components;

sudo npm install mongoose
sudo npm install express
sudo npm install coffee-script
sudo npm install stylus
sudo npm install underscore

And thats all folks!! Now I have Nodejs and its components installed.

Image Capturing from WebCAM using OpenCV and Pygame in Python

John Roach — Wed, 02 Mar 2011 16:03:29 +0000

I know there a lot of examples of WebCAM image capturing on the net. Mine is one of that but the main difference is that this little script here simply captures frames in a certain fps and simply saves those images. There a numerous usages fro such a thing. One usage could be a script that uploads this image to a certain ftp site so you can display it in your web page. I needed this little script to follow a moving object. I did not write the whole script. You may think this as a little upgrade from the one on the internet. The script uses OpenCV and Pygame libs. Without further ado the script :

import pygame
import Image
from pygame.locals import *
import sys

import opencv
import cv

#this is important for capturing/displaying images
from opencv import highgui

camera = highgui.cvCreateCameraCapture(0)
i=0
def get_image():
    im = highgui.cvQueryFrame(camera)
    # Add the line below if you need it (Ubuntu 8.04+)
    #im = opencv.cvGetMat(im)
    #convert Ipl image to PIL image
    return opencv.adaptors.Ipl2PIL(im)

fps = 25.0
pygame.init()
window = pygame.display.set_mode((640,480))
pygame.display.set_caption("WebCAM Demo")
screen = pygame.display.get_surface()

while True:
    events = pygame.event.get()
    for event in events:
        if event.type == QUIT or event.type == KEYDOWN:
            sys.exit(0)
    im = get_image()
    if i>100:
	#allowing the camera to focus
	#auto focus is really annoying
        im.save("image_"+str(i)+"", "JPEG")
    i=i+1
    pg_img = pygame.image.frombuffer(im.tostring(), im.size, im.mode)

    screen.blit(pg_img, (0,0))
    pygame.display.flip()
    pygame.time.delay(int(1000 * 1.0/fps))

Why mysql_real_escape_string() isn’t enough to stop SQL injection attacks!

John Roach — Thu, 17 Feb 2011 11:56:11 +0000

We have all been there writing PHP code and trusting mysql_real_escape_string(). Alas it seems it is not enough, let us look at the example below ;

$id = “0; DELETE FROM users”;
$id = mysql_real_escape_string($id); // 0; DELETE FROM users
mysql_query(“SELECT * FROM users WHERE id={$id}”);

As you can see above simply using mysql_real_escape_string is not enough because the new output is in the end “0; Delete from users”.

However don’t fret dear reader because there is a solution! Make sure the $id is indeed only a number! This can be done by simply using the code below;

$id = “123; DELETE FROM users”;
$id = (int) $id; // 123

This way any string elements will simply won’t be added the system. Now a question may arise on how to make sure you don’t get injected with attack if the parameter is in fact a string. My answer is simply : USE THE FRICKEN SQL QUOTES! Like below;

$username = "DELETE FROM users";
$username = mysql_real_escape_string($username);
mysql_query(“SELECT * FROM users WHERE username='{$username}' ”);

The quotes will allow some protection.

I hope this helps you all! And please don’t tell newbies that mysql_real_escape_string() is enough! IT IS NOT!

Getting raw data from a USB mouse in Linux using Python

John Roach — Wed, 16 Feb 2011 07:15:32 +0000

If you are geek your mouth should be watering by now. I will like to thank Oscar Lindberg and his cool Linux friend for this code! I was trying to get multiple-mice movement data. This is the code that got me started. Once I beautify my multiple-mouse code I will be posting it here as well. Without further ado :

mouse = file('/dev/input/mouse0')
while True:
    status, dx, dy = tuple(ord(c) for c in mouse.read(3))

    def to_signed(n):
        return n - ((0x80 & n) << 1)

    dx = to_signed(dx)
    dy = to_signed(dy)
    print "%#02x %d %d" % (status, dx, dy)

I hope this just made your day!

Getting VGA output using VHDL and a Spartan-3AN board

John Roach — Sat, 15 Jan 2011 14:19:39 +0000

Hi there! Have been busy busy and busy! And you know what that means! New Code!

We were given a homework to write a game for the Spartan-3AN board. Our team decided to write a Simon Says game.(http://en.wikipedia.org/wiki/Simon_(game)) I was responsible for writing the VGA output of the program. I must say it was fun! ( I split the post as there a lot of images in this post )

So there are a few things you must know first about the Spartan-3AN board. The VGA output actually looks like as below;

The top 510 Ohms is where you want your connections. You must also follow the standard connection guidelines for your UCF file. Your VGA connections must be as below;

The other thing you must know is that the output does not has to be a std_logic_vector type unless you want lots of colors. Since the Simon Says game uses only a few colors ( 4 main colors ) I decided to go easy on the board and instead of std_logic_vector for color outputs I simply used std_logic.

You must always keep in mind that the CRT screen acts like as below;

Below you will find a sample code that simply paints the screen… red! Why red you may ask? Because it’s my girlfriends favorite color!

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity clockmodule is
  port(clk50_in  : in std_logic;
       red_out   : out std_logic;
       green_out : out std_logic;
       blue_out  : out std_logic;
       hs_out    : out std_logic;
       vs_out    : out std_logic);
end clockmodule;

architecture Behavioral of clockmodule is

signal clk25              : std_logic;
signal horizontal_counter : std_logic_vector (9 downto 0);
signal vertical_counter   : std_logic_vector (9 downto 0);

begin

-- generate a 25Mhz clock
process (clk50_in)
begin
  if clk50_in'event and clk50_in='1' then
    if (clk25 = '0') then
      clk25 <= '1';
    else
      clk25 <= '0';
    end if;
  end if;
end process;

process (clk25)
begin
  if clk25'event and clk25 = '1' then
    if (horizontal_counter >= "0010010000" ) -- 144
    and (horizontal_counter < "1100010000" ) -- 784
    and (vertical_counter >= "0000100111" ) -- 39
    and (vertical_counter < "1000000111" ) -- 519
    then

     --here you paint!!
       red_out <= '1';
      green_out <= '0';
      blue_out <= '0';

    else
      red_out <= '0';
      green_out <= '0';
      blue_out <= '0';
    end if;
    if (horizontal_counter > "0000000000" )
      and (horizontal_counter < "0001100001" ) -- 96+1
    then
      hs_out <= '0';
    else
      hs_out <= '1';
    end if;
    if (vertical_counter > "0000000000" )
      and (vertical_counter < "0000000011" ) -- 2+1
    then
      vs_out <= '0';
    else
      vs_out <= '1';
    end if;
    horizontal_counter <= horizontal_counter+"0000000001";
    if (horizontal_counter="1100100000") then
      vertical_counter <= vertical_counter+"0000000001";
      horizontal_counter <= "0000000000";
    end if;
    if (vertical_counter="1000001001") then
      vertical_counter <= "0000000000";
    end if;
  end if;
end process;

end Behavioral;

Everything else is straight forward after this actually. All you have to do is to follow which point you are on. If you are good enough you can draw a simple Simon Says interface like below;

Mid-rise type quantizer

John Roach — Thu, 25 Nov 2010 22:45:35 +0000

A mid-rise type quantizer for my DSP lab course. The question is as below.

Generate a discrete-time sinusoidal signal x[n] with the SinSamples() function implemented in preliminary work of experiment 1, with the parameters: A=3, w=2*pi, ws=2*pi*50, .θ=0, d=2sec. Implement 3-bit midrise type quantizer. Make the reconstruction levels be spaced so as to span the entire amplitude range of the signal. You may use the maximum amplitude of the signal in designing reconstruction levels. Plot original signal, quantized version, and quantization error. Calculate output signal to noise ratio in dB (all signal to noise ratios must be calculated in dB).

Generate a discrete-time sinusoidal signal x[n] with the SinSamples() function implemented in preliminary work of experiment 1, with the parameters: A=3, w=2*pi, ws=2*pi*50, .θ=0, d=2seca) Implement 3-bit midrise type quantizer. Make the reconstruction levels be spaced so as to span the entire amplitude range of the signal. You may use the maximum amplitude of the signal in designing reconstruction levels. Plot original signal, quantized version, and quantization error. Calculate output signal to noise ratio in dB (all signal to noise ratios must be calculated in dB).

A=3;
w=2*pi
w_s=2*pi*50;
d=2;
teta=0;
 
f = w/(2*pi);
T = 1/f;
tmin = 0;
dt = T/100;
dt1 = 1/(w_s/(2*pi));
t = tmin:dt:d;
t1 = tmin:dt1:d;
x = A*sin(w*t+teta);
x1 = A*sin(w*t1+teta);
subplot(3,1,1);
plot(t,x,'r');
hold on
stem(t1,x1);
title('The sampled and original signal');
xlabel(''), ylabel('amplitude');
grid on;
hold on
 
% Quatization part (midrise)
bit=3; %number of bits that will be used
signal=x1; %get the signal
m_max=max(abs(signal)); %find the highest magnitude used
delta=(2*m_max)/(2^bit) ;  %our step size
k_max=(2^bit)/2; %how many levels we have in one side of the quatization graph
for i=1:length(signal)
    for k=0:1:(k_max-1)
        if (((k*delta)<=abs(signal(i)))&&(abs(signal(i))<=((k+1)*delta)))
            if(signal(i)>0)
                new_signal(i)=(0.5+k)*delta;
            elseif(signal(i)<0)
                new_signal(i)=(-0.5-k)*delta;
            elseif(signal(i)==0)    
                new_signal(i)=0;
            end 
        end
 
    end
end
subplot(3,1,2);
stem(t1,new_signal);
xlabel(''), ylabel('amplitude');
grid on;
hold on
 
error=signal-new_signal;
subplot(3,1,3);
stem(t1,error);
xlabel(''), ylabel('amplitude');
grid on;
hold on

And the output is as below;

Plotting and finding the magnitude of a wav file in MATLAB[edited]

John Roach — Wed, 20 Oct 2010 19:14:00 +0000

Edited: Changed code to a more correct version!
The question was;

Load the file sound1.wav(Download from here => SoundWav (125) ) (You would use MATLAB command ‘wavread’ to loadthis file. Use MATLAB help to learn the usage of ‘wavread’). This file contains a portion of speech waveform. Take the first 512 point the signal, plot the waveformand its magnitude spectrum.

%call it like question_8('sound1.wav')
function question_8(url)
[x,fs]=wavread(url);
new_x=x(1:512);
subplot(2,1,1);
stem(new_x);
title('The sampled sound signal');
xlabel('time'), ylabel('amplitude');
grid on;
hold on
 
 
subplot(2,1,2)
N=(fs/2)*linspace(-1,1,length(x));
stem(N,fftshift(abs(fft(new_x))));
 
title('Sampled signal at frequency-domain');
xlabel('frequency'), ylabel('amplitude');
grid on;
end