window

Open a window and draw to it

The window package brings OSL's original graphical model to compiled programs: you open a real desktop window and draw into it every frame using OSL's rendering commands (the "draw cursor", shapes, text, icons and 3D). This is the same drawing model that powered originOS apps.

import "osl/window"

Program structure

A windowed program has two parts:

1. Setup - top-level statements that run once. Configure the window and load assets here.

2. The main loop - everything after the mainloop: label runs once per frame. This is where you read input and draw.

import "osl/window"

window.setTitle("Hello OSL")
window.setColor("#ffffff")
window.show()
window.resize(800, 450)

number x = 0

mainloop:

x += 1
goto x window.top - 40
centext "hello world" 10 : c#000

mainloop: is a bare label - it has no parentheses and no body brackets. Everything below it is the per-frame loop, and it keeps running until the window closes.

Window properties & methods

Read the window's size and edges as properties (no parentheses):

window.width      window.height
window.left       window.right
window.top        window.bottom

Control the window with methods:

Method	Purpose
window.setTitle(title)	Set the title bar text.
window.setColor(hex)	Set the background colour.
window.show() / window.hide()	Show or hide the window.
window.resize(w, h)	Resize the window.
window.setResizable(bool)	Allow or block user resizing.
window.fullscreen() / window.isFullscreen()	Toggle / query fullscreen.
window.minimise()	Minimise.
window.close()	Close the window and stop the program.
window.on(event, handler)	Listen for window events.

Drawing

Inside the loop you draw with rendering commands. They operate on a moving "draw cursor":

goto x y                 // move the draw cursor
change_x n   change_y n  // move it relatively
c "#ff0000"              // set the draw colour
icon iconString size     // draw an ICN icon
image url w h            // draw an image
text "hello" 10          // draw text from the cursor
centext "hello" 10       // draw text centred on the cursor

Many commands accept an inline modifier after a colon - for example : c#000 sets the colour just for that element:

centext "Score: " ++ score 10 : c#000

See the full reference: Rendering basics, Elements, the ICN icon format, clipping & frames, and 3D rendering.

Input

Keyboard keys are queried by name:

if "space".isKeyDown() (
  jump = true
)
move_left  = "a".isKeyDown()
move_right = "d".isKeyDown()

The window package also exposes per-frame global variables you can read directly in the loop:

Global	Meaning
mouse_x, mouse_y	Mouse position.
x_position, y_position	The current draw-cursor position.
direction	The draw cursor's heading (for pen/turtle drawing).
timer	A steadily increasing timer, handy for timing events.

A complete example

import "osl/window"

object player = { x: 0, y: 0 }

window.setColor("#fff")
window.setTitle("Move me")
window.show()
window.resize(800, 450)

mainloop:

if "a".isKeyDown() (
  player.x -= 4
)
if "d".isKeyDown() (
  player.x += 4
)
if "w".isKeyDown() (
  player.y += 4
)
if "s".isKeyDown() (
  player.y -= 4
)

goto player.x.toNum() player.y.toNum()
icon "c #000 square 0 0 20 20" 2

goto 0 window.top - 30
centext "use WASD" 10 : c#000

Companion packages

• win-buttons - add clickable buttons to a window (import "osl/win-buttons").

• sound - play audio in a windowed app.

Heads-up: the window package depends on native graphics libraries, so the first compile pulls in extra dependencies. Server and CLI programs don't need any of this.

Complete API reference

window

Method	Returns	Description
window.on(name: any, callback: any)	void	Runs the on operation.
window.emit(name: any, ...args: any)	void	Runs the emit operation.
window.show()	void	Runs the show operation.
window.Create()	void	Runs the create operation.
window.Goto(x: any, y: any)	void	Runs the goto operation.
window.hide()	void	Runs the hide operation.
window.resize(width: any, height: any)	void	Runs the resize operation.
window.close()	void	Closes the resource.
window.minimise()	void	Runs the minimise operation.
window.fullscreen()	void	Runs the fullscreen operation.
window.isFullscreen()	boolean	Reports whether fullscreen.
window.color()	string	Runs the color operation.
window.setColor(col: any)	void	Sets color.
window.setTitle(title: any)	void	Sets title.
window.keyPressed(key: string)	boolean	Runs the key pressed operation.
window.setResizable(resizable: boolean)	void	Sets resizable.
window.setDragbox(box: any)	void	Sets dragbox.
window.dragbox()	array	Runs the dragbox operation.

Window values

Methods available on Window values returned by this package or constructed by the language.

Method	Returns	Description
value.Run(loop: function)	void	Runs the window loop callback until the window closes.
value.width()	number	Runs the width operation.
value.height()	number	Runs the height operation.
value.left()	number	Runs the left operation.
value.right()	number	Runs the right operation.
value.top()	number	Runs the top operation.
value.bottom()	number	Runs the bottom operation.
value.SetTitle(title: string)	void	Sets title.
value.resize(width: any, height: any)	void	Runs the resize operation.
value.setResizable(resizable: boolean)	void	Sets resizable.
value.Clear(col: color.Color)	void	Runs the clear operation.
value.Update()	void	Runs the update operation.
value.KeyPressed(key: string)	boolean	Runs the key pressed operation.

winRender values

Methods available on winRender values returned by this package or constructed by the language.

Method	Returns	Description
value.Hex(hex: any)	color.RGBA	Runs the hex operation.
value.Color(col: any)	void	Runs the color operation.
value.Goto(x: any, y: any)	void	Runs the goto operation.
value.Loc(a: any, b: any, c: any, d: any)	void	Runs the loc operation.
value.toScreen(x: number, y: number)	pixel.Vec	Converts to screen.
value.drawColor()	color.Color	Runs the draw color operation.
value.Effect(name: any, value: any)	void	Runs the effect operation.
value.penSize()	number	Runs the pen size operation.
value.beginElement()	void	Runs the begin element operation.
value.updateLast(minX: number, minY: number, maxX: number, maxY: number)	void	Runs the update last operation.
value.checkClick()	void	Runs the check click operation.
value.LineTo(endX: number, endY: number)	void	Runs the line to operation.
value.Rect(...args: any)	void	Runs the rect operation.
value.Icon(icon: any, size: number)	void	Runs the icon operation.
value.batchIcon(iconStr: string, size: number, offsetX: number, offsetY: number)	void	Runs the batch icon operation.
value.drawIconCached(iconStr: string, size: number, offsetX: number, offsetY: number)	void	Runs the draw icon cached operation.
value.executeIconCommands(cmds: array, size: number, offsetX: number, offsetY: number)	void	Runs the execute icon commands operation.
value.batchLine(startX: number, startY: number, endX: number, endY: number, thickness: number, col: color.Color)	void	Runs the batch line operation.
value.batchDot(cx: number, cy: number, thickness: number, col: color.Color)	void	Runs the batch dot operation.
value.batchSquare(cx: number, cy: number, hw: number, hh: number, thickness: number, col: color.Color)	void	Runs the batch square operation.
value.batchRect(cx: number, cy: number, w: number, h: number, col: color.Color)	void	Runs the batch rect operation.
value.batchTri(x1: number, y1: number, x2: number, y2: number, x3: number, y3: number, col: color.Color)	void	Runs the batch tri operation.
value.batchCutcircle(cx: number, cy: number, radius: number, dir: number, arclen: number, thickness: number, col: color.Color)	void	Runs the batch cutcircle operation.
value.batchEllipse(cx: number, cy: number, w: number, mult: number, dir: number, thickness: number, col: color.Color)	void	Runs the batch ellipse operation.
value.icnDot(cx: number, cy: number)	void	Runs the icn dot operation.
value.icnSquare(cx: number, cy: number, hw: number, hh: number)	void	Runs the icn square operation.
value.icnRect(cx: number, cy: number, w: number, h: number)	void	Runs the icn rect operation.
value.icnTri(x1: number, y1: number, x2: number, y2: number, x3: number, y3: number)	void	Runs the icn tri operation.
value.icnCutcircle(cx: number, cy: number, radius: number, dir: number, arclen: number)	void	Runs the icn cutcircle operation.
value.icnEllipse(cx: number, cy: number, w: number, mult: number, dir: number)	void	Runs the icn ellipse operation.
value.Text(text: string, size: any)	void	Runs the text operation.
value.Centext(text: string, size: any)	void	Runs the centext operation.
value.SetThickness(thickness: number)	void	Sets thickness.
value.Change(offsetX: number, offsetY: number)	void	Runs the change operation.
value.Direction(dirFloat: number)	void	Runs the direction operation.
value.Turnright(angle: number)	void	Runs the turnright operation.
value.Turnleft(angle: number)	void	Runs the turnleft operation.
value.Pointat(x: number, y: number)	void	Runs the pointat operation.
value.Image(key: string, w: any, h: any)	void	Runs the image operation.

Notes

• Standard-library imports accept both import "osl/window" and import "window".

• Return values such as array and object are regular OSL values unless a returned object section says otherwise.