Circuits and Software
x86 Instruction Chart
9 Volt Battery Chargers
Use your color monitor as an RGB Photography Light
SMPTE Colorbars Test Pattern (in Javascript)
255 Shades of Grey, Red, Green and Blue Test Pattern (in Javascript)
Spice BJT Model Viewer
Ohm's Law Calculator
Prime Factorization
Convert a Decimal Fraction to a Simple Fraction
Solid State Circuit Breaker (20V 650mA)
Example POV-Ray Animation
Example Virtual Machine
Salt Flats & Aeromods
Locating a Gunshot with an Array of Microphones
Audio Amp + Spice References
Image Processing
8087 FPU Instruction Chart
KFC 'Secret' Recipe
Neddy's Brownies
Ham and Cheese Muffins
Railroad Tracks
The Bike Shed
The Guy That Invented Fire
Mods for the TRS-80 Color Computer

Image Processing

Convert Text to a 'C' Subroutine
When you want to embed a large amount of text in your program.

Useful to eliminate dependencies on external resources.

Convert a Binary File to 'C' Unsigned Character Byte Array
When you want to embed binary data, like a jpeg image, into your program.

Using Cairo Graphics Library for Dynamic Web Graphics

Here is an example of a CGI web application that dynamically creates a PNG graphic image and displays it in a web browser without creating an intermediate file.

Download cairohello.c 'C' source code

To compile

gcc cairohello.c -L /usr/local/lib -lcairo
hello.png generated by Cairo Web CGI App

exif: Extract Thumbnails from Digital Photos

exif -e HPIM4809.JPG -o thumb4809.jpg

Extract the thumbnail image from an HP digital photo.

[FreeBSD] / ports / graphics / exif

Most digital cameras produce EXIF files, which are JPEG files with extra tags that contain information about the image. The EXIF library allows you to parse an EXIF file and read the data from those tags.


libgd - Boutelle Graphics - gcc command line

gcc imgpage.c -I /usr/local/include -L /usr/local/lib -lgd

Command line for compiling a C program that uses the GD graphics library.

The GD library creates PNG, JPEG and GIF images, among other formats. GD is commonly used to generate charts, graphics, thumbnails, and most anything else, on the fly. While not restricted to use on the web, the most common applications of GD involve web site development.

LIBGD: the GD library

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