linux-draw.oak

// X11 drawing sample using Linux stdlib wrappers.

{
	println: println
	string: string
} := import('std')
{
	printf: printf
} := import('fmt')

linux := import('linux')

fn drawScene(state, gc) {
	linux.setForeground(state.display, gc, state.black)
	linux.drawString(state.display, state.window, gc, 24, 30, 'Hello from Magnolia + X11')
	linux.drawLine(state.display, state.window, gc, 24, 70, 360, 230)
	linux.fillRectangle(state.display, state.window, gc, 380, 90, 200, 140)
	linux.flush(state.display)
}

fn runLoopAndRedraw(state, eventPtr, gc) {
	step := linux.pumpWindowEvent(state.display, eventPtr)
	if step.type {
		:dispatch -> if step.eventType {
			linux.ClientMessage -> 0
			linux.DestroyNotify -> 0
			linux.Expose -> {
				drawScene(state, gc)
				runLoopAndRedraw(state, eventPtr, gc)
			}
			_ -> runLoopAndRedraw(state, eventPtr, gc)
		}
		:idle -> runLoopAndRedraw(state, eventPtr, gc)
		_ -> step
	}
}

println('== Linux X11 Draw Sample ==')

if linux.isLinux?() {
	true -> {
		state := linux.openDefaultWindow('Magnolia Linux Draw Sample', 900, 560)
		if state.type {
			:ok -> {
				gc := linux.createGC(state.display, state.window, 0, 0)
				if linux.callOk?(gc) & gc.r1 > 0 {
					true -> {
						drawScene(state, gc.r1)
						eventBuf := linux.createXEventBuffer()
						loopResult := runLoopAndRedraw(state, addr(eventBuf), gc.r1)
						printf('Loop ended with: {{ 0 }}', string(loopResult))
						linux.freeGC(state.display, gc.r1)
					}
					_ -> {
						println('XCreateGC failed.')
						println(string(gc))
					}
				}
				linux.closeWindow(state)
			}
			_ -> {
				println('openDefaultWindow failed.')
				println(string(state))
				println('Last error: ' + string(linux.lastErrorMessage()))
			}
		}
	}
	_ -> println('Not on Linux; skipping X11 draw sample.')
}