It is now possible to draw a filled ellipse

artist/ellipse.go

@@ -0,0 +1,34 @@
+package artist
+
+import "math"
+import "image"
+import "git.tebibyte.media/sashakoshka/tomo"
+
+// FillEllipse draws a filled ellipse with the specified pattern.
+func FillEllipse (
+	destination tomo.Canvas,
+	source Pattern,
+	bounds image.Rectangle,
+) (
+	updatedRegion image.Rectangle,
+) {
+	data, stride := destination.Buffer()
+	realWidth, realHeight := bounds.Dx(), bounds.Dy()
+	bounds = bounds.Canon().Intersect(destination.Bounds()).Canon()
+	if bounds.Empty() { return }
+	updatedRegion = bounds
+
+	width,  height := bounds.Dx(), bounds.Dy()
+	for y := 0; y < height; y ++ {
+	for x := 0; x < width;  x ++ {
+		xf := float64(x) / float64(width)  - 0.5
+		yf := float64(y) / float64(height) - 0.5
+		if math.Sqrt(xf * xf + yf * yf) <= 0.5 {
+			data[x + bounds.Min.X + (y + bounds.Min.Y) * stride] =
+				source.AtWhen(x, y, realWidth, realHeight)
+		}
+	}}
+	return
+}
+
+// TODO: StrokeEllipse

artist/line.go

@@ -129,8 +129,8 @@ func squareAround (
 	source Pattern,
 	x, y, patternWidth, patternHeight, diameter int,
 ) {
-	minY := y - diameter
-	minX := x - diameter
+	minY := y - diameter + 1
+	minX := x - diameter + 1
 	maxY := y + diameter
 	maxX := x + diameter
 	for y = minY; y < maxY; y ++ {

artist/rectangle.go

@@ -88,7 +88,3 @@ func StrokeRectangle (
 		insetBounds.Max.X, insetBounds.Min.Y,
 		bounds.Max.X, insetBounds.Max.Y))
 }
-
-// TODO: FillEllipse
-
-// TODO: StrokeEllipse