Anonymous user
Greyscale bars/Display: Difference between revisions
→{{header|Nim}}
(Add Plain English) |
|||
Line 1,110:
display b
</lang>
=={{header|Nim}}==
{{libheader|gintro}}
<lang Nim>import gintro/[glib, gobject, gtk, gio, cairo]
const
Width = 640
Height = 480
#---------------------------------------------------------------------------------------------------
proc draw(area: DrawingArea; context: Context) =
## Draw the greyscale bars.
const
Black = 0.0
White = 1.0
var y = 0.0
var nrect = 8
let rectHeight = Height / 4
# Draw quarters.
for quarter in 0..3:
let rectWidth = Width / nrect
var x = 0.0
var (grey, incr) = if (quarter and 1) == 0: (Black, 1 / nrect) else: (White, -1 / nrect)
# Draw rectangles.
for _ in 1..nrect:
context.rectangle(x, y, rectWidth, rectHeight)
context.setSource([grey, grey, grey])
context.fill()
x += rectWidth
grey += incr
y += rectHeight
nrect *= 2
#---------------------------------------------------------------------------------------------------
proc onDraw(area: DrawingArea; context: Context; data: pointer): bool =
## Callback to draw/redraw the drawing area contents.
area.draw(context)
result = true
#---------------------------------------------------------------------------------------------------
proc activate(app: Application) =
## Activate the application.
let window = app.newApplicationWindow()
window.setSizeRequest(Width, Height)
window.setTitle("Greyscale bars")
# Create the drawing area.
let area = newDrawingArea()
window.add(area)
# Connect the "draw" event to the callback to draw the spiral.
discard area.connect("draw", ondraw, pointer(nil))
window.showAll()
#———————————————————————————————————————————————————————————————————————————————————————————————————
let app = newApplication(Application, "Rosetta.GreyscaleBars")
discard app.connect("activate", activate)
discard app.run()</lang>
=={{header|OCaml}}==
| |||