zard-white

libzard is a lightweight C graphics library that implements a simple software renderer for generating images in the PPM format.

Features

• Minimal, ergonomic API with a begin/end session model
• Pure software rendering — no GPU, no external dependencies
• Primitive drawing support:
  • Lines
  • Rectangles (outline and filled)
  • Circles (outline and filled)
  • Triangles (outline and filled)
• Direct pixel manipulation
• PPM image output (P3 ASCII and P6 binary)
• 2D vector support (zvec2_t) with float precision
• Vector math helpers for composing point-list shapes
• Frame-by-frame animation helpers for generating PPM sequences

About the PPM Format

PPM (Portable Pixmap) is a straightforward image format designed for simplicity and portability. libzard supports both variants:

P3 (ASCII)

P3
<width> <height>
255
R G B R G B R G B ...

P6 (Binary)

P6
<width> <height>
255
<raw binary RGB data>

Each pixel is represented by three 8-bit channel values:

• Red (0–255)
• Green (0–255)
• Blue (0–255)

Example

P3
2 1
255
255 0 0 0 255 0

This produces a 2-pixel wide image consisting of one red pixel followed by one green pixel.

P3 vs P6

Installation

Build

make

Install system-wide

sudo make install

This installs:

• libzard.a → /usr/local/lib
• zard.h → /usr/local/include

Uninstall

sudo make uninstall

Clean

make clean

Usage

Example

Example 1:

#include <zard.h>
int main() {
 zard_begin("output_1.ppm", 400, 300, ZARD_P6);
 zard_clear(ZARD_BLACK);
 zard_line(0, 0, 399, 299, ZARD_WHITE);
 zard_rect(50, 50, 100, 80, ZARD_RED);
 zard_fill_circle(200, 150, 40, ZARD_BLUE);
 zard_end();
 return 0;
}

Example 2:

#include <zard.h>
int main() {
 zard_begin("output_2.ppm", 400, 300, ZARD_P6);
 zard_clear(ZARD_BLACK);
 zvec2_t a = {50.0f, 50.0f};
 zvec2_t b = {350.0f, 250.0f};
 zvec2_t center = {200.0f, 150.0f};
 zard_line_v(a, b, ZARD_WHITE);
 zard_circle_v(center, 40, ZARD_BLUE);
 zard_end();
 return 0;
}

Example 3:

#include <zard.h>
int main() {
 int frames = 60;
 zard_anim_init("output-%02d.ppm", 960, 540, ZARD_P6);
 for (int i = 0; i < frames; i++) {
 zard_frame_begin(i);
 zard_clear(ZARD_BLACK);
 zard_fill_circle(i * 8, 270, 40, ZARD_RED);
 zard_frame_end();
 }
 zard_anim_done(frames);
 return 0;
}

Vector shape example:

#include <math.h>#include <zard.h>
int main() {
 zard_begin("shape.ppm", 400, 400, ZARD_P6);
 zard_clear(ZARD_BLACK);
 float pi = acosf(-1.0f);
 zvec2_t center = zard_vec2(200.0f, 200.0f);
 zvec2_t star[10];
 zard_make_star(star, 5, center, 50.0f, 140.0f, -pi * 0.5f);
 zard_fill_polygon_v(star, 10, ZARD_BLUE);
 zard_polygon_v(star, 10, ZARD_WHITE);
 zard_end();
 return 0;
}

Compile

gcc main.c -lzard -lm -o app

When using the local build without installing system-wide:

gcc main.c -I./src -L./build -lzard -lm -o app

Run examples

make run

Run a single example by name:

make run-one NAME=basic

API Reference

Session

Primitives

Vectorized

Vector Math And Shapes

Animation

Generated frames can be converted with tools such as ffmpeg:

ffmpeg -framerate 60 -i output-%02d.ppm output.mp4

Built-in Colors

ZARD_BLACK, ZARD_WHITE, ZARD_RED, ZARD_GREEN, ZARD_BLUE, ZARD_CYAN, ZARD_MAGENTA, ZARD_YELLOW, ZARD_GRAY, ZARD_ORANGE

Custom colors can be defined with ZARD_RGB(r, g, b).

License

MIT License — Copyright (c) 2026 grassleaff. All Rights Reserved.