Interactive 2D graphics in plain Java

Minvio is a lightweight 2D sketching library for plain Java. It handles the repetitive Java2D setup, creates the application window, and runs the timed update/draw loop so you can focus on graphics, interaction, and experiments.

The API stays small, has no runtime dependencies beyond the JDK, and keeps direct access to standard Java types such as BufferedImage, Color, and Font.

It is designed for:

• Generative and programmatic art
• Algorithm visualization and development
• Experiments and proofs of concept
• Teaching and learning
• Small interactive desktop tools and toys

Minvio is deliberately a lightweight 2D sketch library, not a game engine. For projects that require 3D rendering, GPU shaders, physics, audio, or mobile and web deployment, a larger framework such as Processing, OPENRNDR, libGDX, or FXGL may be a better fit.

Additional examples are available here: https://github.com/nickd3000/minvio-examples

Website with FAQ and Blog posts on the project: https://nickd3000.github.io/minvio/

Installation

Add the Maven dependency:

<dependency>
    <groupId>io.github.nickd3000</groupId>
    <artifactId>minvio</artifactId>
    <version>1.23</version>
</dependency>

Minimal Example

import com.physmo.minvio.MinvioApp;
import com.physmo.minvio.utils.Palette;

class SimpleExample extends MinvioApp {

    public static void main(String... args) {
        MinvioApp app = new SimpleExample();
        app.start(200, 200, "Simple Example", 60);
    }

    @Override
    public void draw(double delta) {
        cls(Palette.SLATE);
        setDrawColor(Palette.AMBER);
        
        drawFilledRect(50, 50, 40, 40);
        drawFilledCircle(120, 70, 20);
        drawCircle(120, 120, 20);
        drawRect(50, 100, 40, 40);

        drawText("X:" + getMouseX() + " Y:" + getMouseY(), 10, 190);

    }
}

2D Drawing API

Minvio includes common outline and filled primitives for circles, ellipses, rectangles, triangles, polygons, polylines, and Java2D Shape objects. Arcs use radians, matching the transform API.

Drawing state includes color, font, stroke width, alpha, composite, and rectangular clipping. Use pushStyle() and popStyle() to make temporary style changes without manually restoring each value:

void drawStyledShape() {
    pushStyle();
    setDrawColor(new Color(70, 170, 255));
    setStrokeWidth(4);
    setAlpha(0.65);
    setClip(20, 20, 160, 100);
    drawFilledEllipse(0, 0, 220, 140);
    popStyle();
}

Transforms use their own independent pushMatrix() and popMatrix() stack.

Examples

Most examples use the high-level MinvioApp style: extend MinvioApp, override init, update, and/or draw, then call start(...). This is the recommended way to write Minvio sketches and small applications.

Examples in this repository live under src/main/java/com/physmo/reference/ and are organized by topic:

• beginner: Java language basics taught with simple visual examples.
• basics: core Minvio app, image, text, resize, timing, and screenshot examples.
• input: keyboard, mouse, and interaction examples.
• drawing: drawing API, style, shape, helper, and pixel-sampling examples.
• concepts: common creative-coding ideas such as particles, forces, collision, color interpolation, transforms, and noise.
• lowlevel: a small set of direct BasicDisplay examples for advanced/manual display-loop control.
• gallery, gui, ecs, experiments, wiki, and rigs: larger sketches, GUI/ECS demos, exploratory tools, and docs-linked examples.

See src/main/java/com/physmo/reference/README.md for a fuller guide to the example packages.

The separate examples repository is here: https://github.com/nickd3000/minvio-examples

Development

Minvio targets Java 17. When running Maven locally, use JDK 17 to avoid JaCoCo trying to instrument newer JDK runtime classes:

JAVA_HOME=$(/usr/libexec/java_home -v 17) PATH="$JAVA_HOME/bin:$PATH" mvn test

More Example Images

Changelist

Version 1.23 - August 2026

• Added Screenshot Functionality
  • Implemented automatic screenshot saving using the F12 key in MinvioApp.
  • Added takeScreenshot() and saveScreenshot() methods with automatic file naming (e.g., AppName_1.png).
  • Added takeScreenshotAndQuit(...) for agent-friendly screenshot capture from examples.
  • Added screenshot APIs that can report success or throw when writing fails.
• Enhanced Drawing Precision
  • Added overloaded drawing methods across MinvioApp and DrawingContext that accept double coordinates (e.g., drawPoint, drawRect, drawText, drawImage) for more sub-pixel precision.
• Added Transformation and State Management (pushMatrix, popMatrix, translate, rotate, scale)
• Added ellipses, triangles, polygon outlines, polylines, arcs, and Java2D Shape drawing.
• Added stroke width, alpha/composite, clipping, and pushStyle/popStyle state management.
• Added Rotations1 gallery example (concentric animated rings)
• Added TransformationExample, FractalTreeExample, and KaleidoscopeExample gallery examples
• Added Fractal Tile example
• Added retro palette constants for C64, ZX Spectrum, BBC Micro, CGA, Game Boy, and MSX-style colors.
• Made Palette color presets immutable constants.
• Improved MinvioApp frame timing so updates run once per rendered frame and frame waits avoid busy-spinning.
• Improved BasicDisplayAwt Swing/input handoff by routing Swing work through the EDT and snapshotting key state.
• Added context-free ECS update methods and deprecated the old DrawingContext update overloads.
• Improved Maven/release hygiene, documentation version references, and artifact contents.
• Expanded automated test coverage for screenshots, ECS compatibility, frame cadence, input snapshots, and palette constants.

Version 1.20 - Aug 2025

• Added Screen resizing functionality
• Added Initial GUI layout support
• Added Palette Class with predefined colours
• Updated to Java 17
• Added Array class for an efficient List style container that avoids reallocation.

Version 1.10 - September 2024

• Gui: Added Label, Slider and text button.
• Gui: Added more color components to GuiContext.
• Cleanup: Moved structure objects to types package.

Version 1.08 - August 2024

• Simplified app startup
• Added pass-through methods in MinvioApp to drawing context

Version 1.07 - May 2023

• Removed all examples - They are now in a separate project - minvio-examples

Version 1.06 - December 23 2021

• Matrix drawer changes
• Added QuickRandom

Version 1.05 - December 13 2021

• Added Entity-Component system
• Added Entity-Component example
• Added Vec3 object
• Added bucket list utility and gravity particle example
• Added Ribbons to gallery projects
• Added getMousePointNormalised

Version 1.04 - October 17 2021

• Added Perlin Noise utility and examples.
• Added colour gradient system and examples.
• Added Matrix and point list rendering helpers with examples.

Version 1.03 - October 10 2021

• Added anchor system.
• Rearranged example file folders.
• Added lerp functions for several types.
• Added FindClosestPointInList helper function.
• Changes to image loading.

http://www.coolbubble.com/cc/ - coolcompare