plot — A Minimal C++ Plotting Library

plot is a small C++ library that wraps SDL2 into a minimal drawing API. It manages the window, renderer, and event loop — you only implement three callbacks.

Download

Dependencies

SDL2, SDL2_ttf, SDL2_image. On Debian/Ubuntu:

apt install libsdl2-dev libsdl2-ttf-dev libsdl2-image-dev

Building

Compile plot.cpp together with your source file:

g++ -std=c++11 -o demo demo.cpp plot.cpp $(sdl2-config --cflags --libs) -lSDL2_ttf -lSDL2_image

Or use the included Makefile:

make

To build a different source file:

make SRC=myprogram.cpp OUT=myprogram

Usage

Include plot.hpp and implement the callbacks. Only frame() is required — all others are optional.

#include "plot.hpp"

void setup() {
    PlotCanvas(640, 480, PLOT_MODE_CROSS);
}

void frame() {
    PlotBackground(255, 255, 255);
    PlotColor(200, 0, 0);
    PlotLine(-100, 0, 100, 0);   // horizontal line through origin
    PlotLine(0, -100, 0, 100);   // vertical line through origin
    PlotText(5, 5, "Frame: %d", g_current_frame);
}

bool event(SDL_Event* e) {
    return false; // return true if event was handled
}

Canvas Modes

PlotCanvas(width, height, mode) sets up the drawing area. The mode controls where the origin is and which direction y increases:

API Reference

// Setup
void PlotCanvas(int width, int height, int mode = PLOT_MODE_DEFAULT);
void PlotMode(int mode);

// Drawing
void PlotBackground(Uint8 r, Uint8 g, Uint8 b);
void PlotColor(Uint8 r, Uint8 g, Uint8 b);
void PlotColor(Uint8 r, Uint8 g, Uint8 b, Uint8 a);
void PlotCross();                                        // draws x/y axes
void PlotPixel(double x, double y);
void PlotLine(double x1, double y1, double x2, double y2);
void PlotTriangle(PlotPoint a, PlotPoint b, PlotPoint c);
void PlotRectangle(double x1, double y1, double x2, double y2);
void PlotFilledRectangle(double x1, double y1, double x2, double y2);
void PlotText(double x, double y, const char* format, ...);  // printf-style

// Timing
void PlotSetFPS(int fps);
void PlotSetFrameDurationMS(Uint32 ms);
void PlotSetFrameLimit(int frames);
uint32_t PlotGetTicks();

// Global state (read-only)
extern int plot_width, plot_height;
extern uint64_t g_current_frame;

All draw functions also accept PlotPoint structs (double x, y) as an alternative to separate coordinates.