SimpleGFX API Quick Reference

Setup & Cleanup

int gfx_init(int width, int height);  // Returns 0 on success, -1 on failure
void gfx_close();                      // Clean up and close window

Display Control

void gfx_clear();                      // Fill window with white
void gfx_present();                    // Show your drawings on screen
void gfx_delay(int ms);                // Pause for milliseconds

Drawing Pixels

void gfx_putpixel(int x, int y);                           // Black pixel
void gfx_putpixel_color(int x, int y, int r, int g, int b); // Colored pixel (RGB 0-255)

Drawing Shapes

void gfx_line(int x1, int y1, int x2, int y2);  // Line from (x1,y1) to (x2,y2)
void gfx_rect(int x, int y, int w, int h);      // Rectangle outline
void gfx_circle(int cx, int cy, int r);         // Circle outline (center + radius)

Text

void gfx_drawtext(int x, int y, const char *text);  // Draw text string

Typical Program Structure

#include "gfx/simplegfx.h"
 
int main() {
    // 1. Initialize
    if (gfx_init(640, 480) != 0)
        return 1;
 
    // 2. Draw things
    gfx_circle(320, 240, 100);
    gfx_drawtext(250, 220, "Hello!");
 
    // 3. Display and wait
    gfx_present();
    gfx_delay(3000);
 
    // 4. Clean up
    gfx_close();
    return 0;
}

Color Examples

// RGB values range from 0-255
gfx_putpixel_color(x, y, 255,   0,   0);  // Red
gfx_putpixel_color(x, y,   0, 255,   0);  // Green
gfx_putpixel_color(x, y,   0,   0, 255);  // Blue
gfx_putpixel_color(x, y, 255, 255,   0);  // Yellow
gfx_putpixel_color(x, y, 255,   0, 255);  // Magenta
gfx_putpixel_color(x, y,   0, 255, 255);  // Cyan
gfx_putpixel_color(x, y, 255, 255, 255);  // White
gfx_putpixel_color(x, y,   0,   0,   0);  // Black

Coordinates

• Origin (0, 0) is at the top-left corner
• X increases going right →
• Y increases going down ↓

(0,0) ────────→ X
  │
  │
  ↓
  Y

Common Patterns

Animation Loop

for (int frame = 0; frame < 100; frame++) {
    gfx_clear();
    // ... draw frame ...
    gfx_present();
    gfx_delay(16);  // ~60 FPS
}

Filled Circle (Manual)

for (int y = cy - r; y <= cy + r; y++) {
    for (int x = cx - r; x <= cx + r; x++) {
        int dx = x - cx;
        int dy = y - cy;
        if (dx*dx + dy*dy <= r*r) {
            gfx_putpixel(x, y);
        }
    }
}

Grid Pattern

for (int y = 0; y < height; y += 10) {
    for (int x = 0; x < width; x += 10) {
        gfx_putpixel(x, y);
    }
}

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📚 Full Documentation

This quick reference covers the basics. For comprehensive documentation:

View Source Documentation

• Header file: gfx/simplegfx.h - Fully documented with Doxygen comments

Generate HTML Documentation

Beautiful, searchable HTML documentation with examples, parameter descriptions, and modern styling:

# 1. First-time setup (download CSS theme)
cd doxygen
bash setup-doxygen.sh
 
# 2. Generate docs (from doxygen folder)
doxygen Doxyfile
 
# 3. View in browser
cd ..
xdg-open docs/html/index.html  # Linux
open docs/html/index.html      # Mac
start docs\html\index.html     # Windows

See README.md - Generating API Documentation for more details.

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SimpleGFX v1.0 - Simple Graphics Library for C Programming Education Made with ❤️ for students learning C