Image Basics

In the first part of this course you will learn the basics of working with images in your computer. Forget Photoshop and illustrator. You 've got the power!

Working with Images

Collecting Images

  1. Pick a topic from the big topic tombola
  2. Go to the Ilm-Park and take 100 photos in 45 minutes
  3.  ???
  4. Profit

Programming Crash Course

Syntax

  • Processing uses Java Syntax
  • A Syntax Error means you got the spelling wrong, or you need to take some grammar lessons.
  • Processing is picky about missing semicolons.
  • Add a semicolon to the end of every line and you're fine (;

Functions

  • Function Calls:
    • function calls can take one or more function arguments given in round braces
    • function calls result in a value (or void)
    • functions can have side effects for example: drawing something on screen.
    • loadImage("park_001.png"); – calling a function to load an image
    • image(i, 0, 0); – calling a function to display an image
  • Examples
  • Functions Definitions:
    • define what argument a function takes (and which types those arguments have)
    • define what a function does
    • define what a function returns (and what type)
    • void draw() – tell the computer what to do to draw a single frame
    • void setup() – tell the computer what to do to set everything up.

Expressions

  • Any combo of numbers and mathematical operators
  • return a result
  • Can be used as argument to a function
  • can be assigned to a variable

Variables

  • In typed languages like Java every variable has a type
  • use variable declaration to tell the computer the variable exists
    • example: int i;
  • use variable definitions to assign a value to a variable
    • example: i = 1;
  • you can combine variable definition and declaration
    • example: int i = 1;'

Types

  • Number Types:
    • float – floating point (Real Numbers), i.e. 0.1, 1e10
    • int – Integer (Whole Number), i.e. 1, -100, 20000
    • byte – 8 bits (Number between -128 and +127)
  • Text Types
    • String – String (Sequence of Characters) i.e. "Processing im Park"
    • char – a single character, i.w. 'A' or 'a' or ' '

If this is all mumbo-jumbo to you, you better be quick, and start learning to code. Here is how to survive:

  1. If you love watching TV check out Dan Shiffmans Vimeo, or go to hello.processing.org (its just 1 hour!) – Highly recommended!
  2. If you prefer to learn by example check out OpenProcessing.org and Sketchbook.cc
  3. If you prefer to read a book, check out the Processing books.

Park Grid Sketch

Let's create our very first program!

  • Loads nine images from our data folde
  • display them in a 3x3 grid on screen
  • scale each picture to 100x100 pixels

park_grid-screenshot.jpg

Source code: park_grid.pde

Interactive Park Sketch

Our very second program ;)

  • Load two images from our data folder
  • Switch between the images every second frame
  • Learn about the power of % a.k.a. modulo a.k.a. division with rest
  • Learning to use Flow control (the if else command)

interactive_park-screenshot.gif

Source code: interactive_park.pde

Homework 1

  • Create a sketch that loads 9 images
    • (feel free to recycle code from our first program)
  • Make the sketch flip through all nine images to create a slideshow / animation
    • Feel free to take inspiration from our second program

Solution

Solution to the homework in progressive steps of abstraction:

Cut-Ups and Collages

This part was about how to create cut-ups, interactive photo puzzles and collages.

Cut-Ups

In this part we will learn how to:

  • use arrays to work with lots of images
  • use loops to let the computer do repetetive tasks
  • create image collages
    • cut up images into stripes and squares
    • rearrange stripes and squares

Simple Tiles Example

We are cutting the original image into 9 tiles and rearrange them.

simple_tiles-screenshot.jpg

Source code: simple_tiles.pde

Final Tiles Example

Here's the final version, that uses variables, arrays and loops to allow for arbitrary number of tiles:

tiles-screenshot.jpg

Source code: tiles.pde

Homework 2

  • Pick an image from the link section below
  • Write a step by step instruction detailing the algorithm
  • Create a processing sketch that applies the algorithm to one of your photos.

Things to keep in mind:

  • Don't tweak my sketch, start from scratch
  • Use comments, to explain your intention

Solution

Links

Collages

Drawing with Images

In this lecture we will learn how to draw with images.

Examples

Sprite Brush 1

sprite_brush_1-screenshot.jpg

Sprite Brush 2

sprite_brush_2-screenshot.jpg

Sprite Brush 3

sprite_brush_3-screenshot.jpg

Sprite Brush 4

sprite_brush_4-screenshot.jpg

Recording im Park

...

Intro to the WikiHaiwaiian for ''fast'' (not an acronym). It is the name for a hypertext system for websites where the user may not only read the content but is also able to change it instantaneously through the browser.

...

Pixel Pushing