package main

import (
    "image"
    "image/color"

    "github.com/codeation/impress"
    "github.com/codeation/impress/event"

    _ "github.com/codeation/impress/duo"
)

func main() {
    app := impress.NewApplication(image.Rect(0, 0, 480, 240), "Hello World Application")
    defer app.Close()

    font := app.NewFont(15, map[string]string{"family": "Verdana"})
    defer font.Close()

    w := app.NewWindow(image.Rect(0, 0, 480, 240), color.RGBA{255, 255, 255, 255})
    defer w.Drop()

    w.Text("Hello, world!", font, image.Pt(200, 100), color.RGBA{0, 0, 0, 255})
    w.Line(image.Pt(200, 120), image.Pt(300, 120), color.RGBA{255, 0, 0, 255})
    w.Show()
    app.Sync()

    for {
        e := <-app.Chan()
        if e == event.DestroyEvent || e == event.KeyExit {
            break
        }
    }
}

See an explanation of the source code in a library overview.

To run this example on Debian/ Ubuntu:

Install gcc, make, pkg-config if you don't have them installed.
Install GTK+ 3 libraries if you don't have them installed:

sudo apt-get install libgtk-3-dev

Build impress terminal from source:

git clone https://github.com/codeation/it.git
cd it
make
cd ..

Then run example:

git clone https://github.com/codeation/impress.git
cd impress
IMPRESS_TERMINAL_PATH=../it/it go run ./examples/simple/

Steps 0-2 are needed to build a impress terminal binary. See impress terminal page for other options for downloading or building impress terminal app.

Technical details

Basic Principles of Library Design:

Performance of the application as well as native applications.
Facade pattern for masking complex components behind an API.
Simple and clean application code.
Minimal library API to follow the Go-way.
Limited use of other libraries (graphic, low-level or native).
Creating a GUI application without form designer or hard-coded widgets.

The main idea is to stay away from the event driven programming paradigm. See "What's wrong with event-driven programming" page.

The library uses a separate application (GTK+ 3 terminal) for drawing instead of binding low-level library to a Golang.

Project State

The project is currently in its beta stage. It is highly suitable for the development of in-house applications.
The project was tested on Debian 12.8 and macOS 15.1.
While the API remains stable, please note that the specific details may be subject to change.

The project roadmap includes both short-term and long-term project stages.

A cross-platform mind-map application is being developed to showcase the core principles of the library.

Up to 2 ms from the moment you press the key, the mind-map application window is redrawn. Measured on a computer with an N200 processor without a video card.