circle-rgb.c File Reference

Advanced example demonstrating pixel-level RGB color manipulation. More...

#include "gfx/simplegfx.h"

Functions
int	main ()

Detailed Description

Advanced example demonstrating pixel-level RGB color manipulation.

Author

Sukesh Ashok Kumar

This example creates a beautiful filled circle with dynamic RGB color gradients. Unlike basic shape drawing, this demonstrates pixel-by-pixel color control, combining geometric calculations with color mathematics.

Mathematical Concepts:

• Distance formula: dist² = (x - cx)² + (y - cy)²
• Circle equation: x² + y² ≤ r² (filled circle)
• Normalized coordinates for color mapping
• Linear interpolation for gradients

Programming Concepts:

• Nested loops for 2D iteration
• Integer distance calculation (avoiding sqrt for performance)
• RGB color components (0-255 range)
• Typecasting to unsigned char
• Gradient calculations using position

What you'll learn:

• How to check if a point is inside a circle
• Creating color gradients based on position
• Efficient distance calculation without square root
• RGB color theory and mixing
• Using gfx_putpixel_color() for custom colors
• Bounding box optimization (only checking pixels near circle)

Color Gradient Explanation:

• Red: varies from left to right (horizontal gradient)
• Green: varies from top to bottom (vertical gradient)
• Blue: varies by distance from center (radial gradient)

Compile:

gcc circle-rgb.c gfx/simplegfx.c -o output/circle-rgb -lX11

Run:

./output/circle-rgb

Function Documentation

main()

int main

(

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