Posts on ZK Punk

Flood Fill: Recursion versus Iterative Solution

Wed, 25 Jan 2023 20:09:10 +0530

Last Run on Python 3.11.1

Intro Link to heading

I have been working on a SwiftUI app to develop a Pixel Editor inspired by the simplicty of the pico8 fantasy game console. One of the most common feature in a drawing application apart from the pencil tool … doh =P, is the bucket tool. The bucket tool performs a flood fill operation, which basically as the name suggests floods the screen and/or a region in the canvas with the selected color.

Hello 2023

Tue, 17 Jan 2023 16:25:02 +0530

Is 2023 the year I blog more frequently? Link to heading

I have been blogging on/off for the past decade. This is another attempt at rekindling the fire. The motivation this time is that I would like to maintain a central repository of all the various projects/ideas I have worked on …

In the last few years I have done some side projects like building a webapp to generate Alexa Skills with no code. A few iOS games using SpriteKit, mobile/web games in love2d, pico8, webapps in React, web3 apps for EVM chains like Ethereum, Polygon, Avalanche and generative art in Processing.

Select Sections From Images of Newspaper clippings, receipts etc Using Opencv and Python

Wed, 25 Sep 2019 13:53:05 -0500

We often take pictures of menus, receipts, and message boards etc. They are often not aligned properly. In this post, I will show you how to select the pertinet parts and allign them as correctly as possible.

Original	Processed

Let’s get started.

1. Find the anchor points Link to heading

We will first load the image of a newspaper clipping containing the sudoku puzzle. Next, we will find out the cordinates of the four corners of the puzzle in the original image.

Create and apply simple filters to an image using OpenCV and Python

Mon, 16 Sep 2019 13:55:46 -0500

In this blog post, I will show you how we can enhance our images using colored filters and add border backgrounds.

Original	Original w/ color filter	Original w/ color border

Let’s get started.

1. Simple color filter Link to heading

Lets start with first creating a color filter - an image with just a single color. This is as simple as creating a 3-D array and filling each pixel with the same value. In the code below I create an array of the same size (682,512,3) as that of the target image and fill each pixel with the color red (0,0,255).

Adding text to an image using OpenCV and Python

Thu, 22 Aug 2019 23:08:06 -0700

In a series of upcoming blog posts, I will be using OpenCV to manipulate images. In this post, I will be adding text to an image (below), I took of a Dervish monastery at the beautiful village of Blagaj in Bosnia.

Resized Original	Resized Original w/ text

Lets get started.

Read Image
Resize Image by aspect ratio
Add text to resized image
Save resized image with text

1. `cv2.imread()` - Read an Image Link to heading

The function cv2.imread() takes a path to the image file and reads it into a variable for further computations. You can use cv2.imshow() to display the image. However, the execution would be so fast, that you won’t be able to see the picture loaded. Hence, you would want to pause the program while it’s displaying the image using cv2.waitKey().

WC implementation in Go Lang

Mon, 11 Mar 2019 00:21:00 -0800

Continuing the theme of exploring Go Lang, today I will be writing a simple version of the Unix utility wc that displays the number of lines, words, and bytes contained in each input file.

This exploration process will involve the following pieces

Getting a file name from command line. os
Opening the file for reading. os
Reading the contents of the file. bufio
Count the lines, words and bytes. unicode
Display the results.

1. Read filename from the commandline Link to heading

Any arguments typed after the programs named are passed into the os.Args array with the name of the program accessible at the first index.

Exploring filesystem in golang

Wed, 06 Mar 2019 00:12:00 -0800

I am currently dabbling in [GoLang] go-lang and trying to get familiar with it’s syntax and style of programming. I also want to get familiar with the built-in packages for basic tasks witout having to google for basic features.

In this post I will be working my way up to building a simple program that can list the files of a given path to it as a command line argument.

1. Print to console Link to heading

Lets start with a simple program that can print a statement to the console using the "fmt" package and the "Println()" fucntion.

ls implementation in python3

Thu, 28 Feb 2019 00:08:00 -0800

“ls” is unix utility that lists the files and directories in the current path or a user passed path. In this post we will explore how to achive such a basic implementation if it using python. Lets explore the ls command line utility.

Some basic information Link to heading

First, we execute ls command line utility to get some preliminary information of a directory. Here is an example of the output from the ls command on a sample directory.

Using Python's map() AND reduce()

Sun, 29 Jan 2012 00:08:00 -0800

Sum of the Squares of the first 5 numbers Link to heading

In this post I will try to use the map() and reduce() functions to compute the sum of the squares of the first five numbers. The map() function takes a function and an iterable as a parameter. The items of the iterable are fed to the function to create a new list. The reduce() function also takes a function and an iterable as a parameter. However, this takes two arguments cumulatively to the items of iterable, from left to right, so as to reduce the iterable to a single value.

What is memoization?

Sat, 07 Jan 2012 00:08:00 -0800

Memoization is a computer science concept to optimize programs by avoiding computations that have already been done and to reuse it. This is achieved by storing the computaions in a lookup table and retrieving them if a need for it arrives in a future computation step.

Now, lets try to walk this concept using a Fibonacci series where each number in the series is sum of the previous two numbers. In the subsequent code, we are trying to find the value of the N’th term in the series.

Traceroute implementation using scapy

Wed, 28 Sep 2011 00:08:00 -0800

Traceroute Link to heading

Traceroute is a network diagnostic utility used for displaying the path taken by a packet to it’s destination. It uses the ICMP protocol to help traverse the path. Each IP packet has an 8 bit TTL field that gets decremented by every router on the path, to prevent the packet from indefinitely circulating the internet (or network). When the TTL value reaches zero an ICMP error ‘Time To Live Exceeded’ is sent back to the sender. We can use this fact to our advantage by discovering all the hops between the source and the destination.

Dropbox: LAN Sync Protocol

Sat, 10 Sep 2011 00:08:00 -0800

A year ago, I fired up wire shark on my home network to check out the packet flow of the DHCP process. I closed all my browser windows and other chat/im services, and still noticed a lot of chatter on the network. One that got my particular attention was a packet that was related to the popular service dropbox. I had not updated/edited any files recently, so was surprised to see it. I then decided to dig a little more on wire shark and with some google search came to the conclusion that it was a dropbox feature to sync data changes within the local network.

How does DHCP work?