GMagic is a simple polygon and line editor, developed to prepare 128x128, 16 color graphics for use on the PICO-8. By using only lines and polygons to compose images, the compressed image data can be shared with PICO-8 renderers and use very little cart space for complex animations. It's basically an extremely simple vector graphics editor.
GMagic is loosely inspired by the Graphics Magician Picture Painter, software used in the late 70s and early 80s to design graphics for adventure games and other programs of the time.
Starting the app
To run locally, download the repo, then open a terminal in the folder. Run:
yarn yarn start
This should start the editor at localhost:3000.
The main concept that drives this editor is that drawings will be composed solely of layered polygons and polylines (chains of lines). These two sorts of drawing methods are referred to as commands from here on, because they can be thought of as tasks for the software to accomplish drawing.
The workspace is broken out into 3 main sections: the Canvas in the upper left of the page, the Commands List in the upper right, and the Tools Palette along the bottom.
The Canvas is where you can view and edit your drawing. There are zoom in/out buttons for adjusting your view, and you will spend most of your time adjusting points in this section.
The Commands List
The Commands List describes the stacking order of all of the polygons and lines in your drawing. Each command has a text box for the name of the command, a glyph indicating the type of command (
Clicking on a command in the Commands List turns it gray, and clicking it again turns it back white. When a command in the Commands List is gray, it is considered the active command. That means that you can use the tools in the Tools Palette to manipulate its properties.
The Tools Palette
In the Tools Palette are three main sections: a set of buttons, two color palettes, and a checkbox grid.
The Add Line button lets you start drawing a line by clicking on the Canvas. When you're done drawing the line, simply click the line's command in the Commands List to stop it from being the active command. Similarly, Add Polygon lets you start drawing a new filled-in shape.
Add Background is just a special-case version of Add Polygon - it's a preset that draws a polygon box to cover the Canvas, and the new command places itself in back of all of your other commands.
While a command is active, three new buttons will appear in this menu: Add Points, Edit Points, and Move Points. Add Points is simple, in that when it is selected (it will have a blue border) and you click on the Canvas, a new point will be added after the last point you added to the command. You might need to switch to Edit Points and move things around to your liking. Edit Points lets you drag existing points to new locations on the Canvas, and Move Points lets you drag whole commands around.
Import/Export calls up a modal that lets you import a drawing previously exported as JSON, and also save your drawing as either JSON or proprietary PICO-8 markup. PICO-8 doesn't have polygon and polyline commmands, so I've written some myself. This section will be updated when the code is ready to share.
The Help Button brings you to this readme!
The Color Palettes let you control the primary and secondary colors for the active command. They work in tandem with the grid of checkboxes, called the Pattern Toggle. With a polygon command selected, try clicking a color in each color palette, then checking and unchecking the boxes in the Pattern Toggle. You should see that the pattern made by the checkboxes determines how the colors you selected fill the polygon. There are lots of interesting combinations possible using this method - try experimenting with different patterns!
Using your drawings in PICO-8
You can find the draw functions necessary in PICO-8.lua. There are commented out yield() statements, in case you want to use the functions in a coroutine for a "draw-in" effect.