Xiaolin Wu's line algorithm: Difference between revisions
Added Wren
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label .wu.l -image $img
pack .wu.l</lang>
=={{header|Wren}}==
{{trans|Kotlin}}
{{libheader|DOME}}
<lang ecmascript>import "graphics" for Canvas, Color
import "dome" for Window
import "math" for Math
class XiaolinWu {
construct new(width, height) {
Window.title = "Xiaolin Wu's line algorithm"
Window.resize(width, height)
Canvas.resize(width, height)
}
init() {
Canvas.cls(Color.white)
drawLine(550, 170, 50, 435)
}
plot(x, y, c) {
var col = Color.rgb(0, 0, 0, c * 255)
x = ipart(x)
y = ipart(y)
Canvas.ellipsefill(x, y, x + 2, y + 2, col)
}
ipart(x) { x.truncate }
fpart(x) { x.fraction }
rfpart(x) { 1 - fpart(x) }
drawLine(x0, y0, x1, y1) {
var steep = Math.abs(y1 - y0) > Math.abs(x1 - x0)
if (steep) drawLine(y0, x0, y1, x1)
if (x0 > x1) drawLine(x1, y1, x0, y0)
var dx = x1 - x0
var dy = y1 - y0
var gradient = dy / dx
// handle first endpoint
var xend = Math.round(x0)
var yend = y0 + gradient * (xend - x0)
var xgap = rfpart(x0 + 0.5)
var xpxl1 = xend // this will be used in the main loop
var ypxl1 = ipart(yend)
if (steep) {
plot(ypxl1, xpxl1, rfpart(yend) * xgap)
plot(ypxl1 + 1, xpxl1, fpart(yend) * xgap)
} else {
plot(xpxl1, ypxl1, rfpart(yend) * xgap)
plot(xpxl1, ypxl1 + 1, fpart(yend) * xgap)
}
// first y-intersection for the main loop
var intery = yend + gradient
// handle second endpoint
xend = Math.round(x1)
yend = y1 + gradient * (xend - x1)
xgap = fpart(x1 + 0.5)
var xpxl2 = xend // this will be used in the main loop
var ypxl2 = ipart(yend)
if (steep) {
plot(ypxl2, xpxl2, rfpart(yend) * xgap)
plot(ypxl2 + 1, xpxl2, fpart(yend) * xgap)
} else {
plot(xpxl2, ypxl2, rfpart(yend) * xgap)
plot(xpxl2, ypxl2 + 1, fpart(yend) * xgap)
}
// main loop
var x = xpxl1 + 1
while (x <= xpxl2 - 1) {
if (steep) {
plot(ipart(intery), x, rfpart(intery))
plot(ipart(intery) + 1, x, fpart(intery))
} else {
plot(x, ipart(intery), rfpart(intery))
plot(x, ipart(intery) + 1, fpart(intery))
}
intery = intery + gradient
x = x + 1
}
}
update() {}
draw(alpha) {}
}
var Game = XiaolinWu.new(640, 640)</lang>
=={{header|Yabasic}}==
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