From b8e473b069d9c81e2f6a471fa7636c27cee63fae Mon Sep 17 00:00:00 2001
From: historia <[not public]>
Date: Tue, 23 Jun 2026 04:38:06 -0400
Subject: initial commit

---
 tools.go | 385 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 385 insertions(+)
 create mode 100644 tools.go

(limited to 'tools.go')

diff --git a/tools.go b/tools.go
new file mode 100644
index 0000000..e745892
--- /dev/null
+++ b/tools.go
@@ -0,0 +1,385 @@
+package main
+
+import "fmt"
+
+// Brush applies terrain to a block centered at p. Each cell gets independent random color.
+func Brush(m *Map, center Point, terrain int, size int, palette []Terrain) {
+	half := size / 2
+	for dy := -half; dy <= half; dy++ {
+		for dx := -half; dx <= half; dx++ {
+			color := ""
+			if terrain >= 0 && terrain < len(palette) {
+				color = palette[terrain].PickColor()
+			}
+			m.SetCell(Point{center.X + dx, center.Y + dy}, terrain, color)
+		}
+	}
+}
+
+// ThickenPoints expands a set of points by the given brush size, returning deduplicated points.
+func ThickenPoints(pts []Point, size int) []Point {
+	if size <= 1 {
+		return pts
+	}
+	half := size / 2
+	seen := make(map[Point]bool)
+	var result []Point
+	for _, p := range pts {
+		for dy := -half; dy <= half; dy++ {
+			for dx := -half; dx <= half; dx++ {
+				np := Point{p.X + dx, p.Y + dy}
+				if !seen[np] {
+					seen[np] = true
+					result = append(result, np)
+				}
+			}
+		}
+	}
+	return result
+}
+
+// FloodFill fills a contiguous area from start with terrain.
+func FloodFill(m *Map, start Point, terrain int, palette []Terrain) {
+	if !m.InBounds(start) {
+		return
+	}
+	target := m.CellAt(start).Terrain
+	if target == terrain {
+		return
+	}
+	color := ""
+	if terrain >= 0 && terrain < len(palette) {
+		color = palette[terrain].PickColor()
+	}
+	type pt struct{ x, y int }
+	stack := []pt{{start.X, start.Y}}
+	visited := make([][]bool, m.Height)
+	for i := range visited {
+		visited[i] = make([]bool, m.Width)
+	}
+	for len(stack) > 0 {
+		p := stack[len(stack)-1]
+		stack = stack[:len(stack)-1]
+		if !m.InBounds(Point{p.x, p.y}) || visited[p.y][p.x] {
+			continue
+		}
+		if m.Grid[p.y][p.x].Terrain != target {
+			continue
+		}
+		visited[p.y][p.x] = true
+		m.SetCell(Point{p.x, p.y}, terrain, color)
+		stack = append(stack, pt{p.x + 1, p.y}, pt{p.x - 1, p.y}, pt{p.x, p.y + 1}, pt{p.x, p.y - 1})
+	}
+}
+
+// BresenhamLine returns points along a line from a to b.
+func BresenhamLine(a, b Point) []Point {
+	var pts []Point
+	x0, y0 := a.X, a.Y
+	x1, y1 := b.X, b.Y
+	dx := abs(x1 - x0)
+	dy := -abs(y1 - y0)
+	sx, sy := 1, 1
+	if x0 > x1 {
+		sx = -1
+	}
+	if y0 > y1 {
+		sy = -1
+	}
+	err := dx + dy
+	for {
+		pts = append(pts, Point{x0, y0})
+		if x0 == x1 && y0 == y1 {
+			break
+		}
+		e2 := 2 * err
+		if e2 >= dy {
+			err += dy
+			x0 += sx
+		}
+		if e2 <= dx {
+			err += dx
+			y0 += sy
+		}
+	}
+	return pts
+}
+
+func abs(x int) int {
+	if x < 0 {
+		return -x
+	}
+	return x
+}
+
+// DrawRect returns points for the outline (or fill) of a rectangle.
+func DrawRect(a, b Point, filled bool) []Point {
+	x0, x1 := a.X, b.X
+	y0, y1 := a.Y, b.Y
+	if x0 > x1 {
+		x0, x1 = x1, x0
+	}
+	if y0 > y1 {
+		y0, y1 = y1, y0
+	}
+	var pts []Point
+	if filled {
+		for y := y0; y <= y1; y++ {
+			for x := x0; x <= x1; x++ {
+				pts = append(pts, Point{x, y})
+			}
+		}
+		return pts
+	}
+	for x := x0; x <= x1; x++ {
+		pts = append(pts, Point{x, y0}, Point{x, y1})
+	}
+	for y := y0 + 1; y < y1; y++ {
+		pts = append(pts, Point{x0, y}, Point{x1, y})
+	}
+	return pts
+}
+
+// DrawCircle returns points for the outline (or fill) of a circle.
+func DrawCircle(center, edge Point, filled bool) []Point {
+	r2 := (edge.X-center.X)*(edge.X-center.X) + (edge.Y-center.Y)*(edge.Y-center.Y)
+	r := r2
+	if r < 0 {
+		return nil
+	}
+	// integer sqrt approximation, good enough for grid
+	radius := intSqrt(r)
+	var pts []Point
+	for dy := -radius; dy <= radius; dy++ {
+		for dx := -radius; dx <= radius; dx++ {
+			dist2 := dx*dx + dy*dy
+			if filled {
+				if dist2 <= r {
+					pts = append(pts, Point{center.X + dx, center.Y + dy})
+				}
+			} else {
+				// outline: approximate ring
+				if dist2 <= r && dist2 > (radius-1)*(radius-1) {
+					pts = append(pts, Point{center.X + dx, center.Y + dy})
+				}
+			}
+		}
+	}
+	return pts
+}
+
+// DrawOval returns points for the outline (or fill) of an ellipse with two foci.
+func DrawOval(f1, f2 Point, filled bool) []Point {
+	// semi-major axis: enough to pass through f2 from f1, plus a bit
+	dx := f2.X - f1.X
+	dy := f2.Y - f1.Y
+	// Use distance between foci as 2c, major axis 2a = 2c * 1.5 (so oval extends)
+	dist := intSqrt(dx*dx + dy*dy)
+	if dist == 0 {
+		return nil
+	}
+	a := dist * 3 / 2 // major semi-axis (oval extends beyond both foci)
+	if a < 1 {
+		a = 1
+	}
+	a2 := a * a
+	c2 := dist * dist / 4 // c = half distance between foci
+	b2 := a2 - c2        // b² = a² - c²
+	if b2 < 0 {
+		b2 = 0
+	}
+
+	// Center of ellipse
+	cx := (f1.X + f2.X) / 2
+	cy := (f1.Y + f2.Y) / 2
+
+	// Bounding box
+	minX := cx - a - 1
+	maxX := cx + a + 1
+	minY := cy - a - 1
+	maxY := cy + a + 1
+
+	var pts []Point
+	for py := minY; py <= maxY; py++ {
+		for px := minX; px <= maxX; px++ {
+			// Distances to foci
+			d1 := distSq(px, py, f1.X, f1.Y)
+			d2 := distSq(px, py, f2.X, f2.Y)
+			sum := intSqrt(d1) + intSqrt(d2)
+
+			if filled {
+				if sum <= 2*a {
+					pts = append(pts, Point{px, py})
+				}
+			} else {
+				// Outline: near the ellipse boundary
+				if sum >= 2*a-1 && sum <= 2*a+1 {
+					pts = append(pts, Point{px, py})
+				}
+			}
+		}
+	}
+	return pts
+}
+
+func distSq(x1, y1, x2, y2 int) int {
+	dx := x1 - x2
+	dy := y1 - y2
+	return dx*dx + dy*dy
+}
+
+func intSqrt(n int) int {
+	if n <= 0 {
+		return 0
+	}
+	lo, hi := 0, n
+	for lo < hi {
+		mid := (lo + hi + 1) / 2
+		if mid*mid <= n {
+			lo = mid
+		} else {
+			hi = mid - 1
+		}
+	}
+	return lo
+}
+
+// ApplyPoints writes terrain to all given points.
+func ApplyPoints(m *Map, pts []Point, terrain int, palette []Terrain) {
+	color := ""
+	if terrain >= 0 && terrain < len(palette) {
+		color = palette[terrain].PickColor()
+	}
+	for _, p := range pts {
+		m.SetCell(p, terrain, color)
+	}
+}
+
+// PlaceTextLabel adds a text label at start, clearing any prior text in those cells.
+func PlaceTextLabel(m *Map, start Point, text string, color string) {
+	// Remove any existing label starting at the same point
+	RemoveTextLabel(m, start)
+	tl := TextLabel{Text: text, Start: start, Color: color}
+	m.TextLabels = append(m.TextLabels, tl)
+	runes := []rune(text)
+	for i, r := range runes {
+		p := Point{start.X + i, start.Y}
+		if m.InBounds(p) {
+			m.Grid[p.Y][p.X].Text = string(r)
+		}
+	}
+}
+
+// RemoveTextLabel removes the text label starting at start.
+func RemoveTextLabel(m *Map, start Point) {
+	for i, tl := range m.TextLabels {
+		if tl.Start == start {
+			m.TextLabels = append(m.TextLabels[:i], m.TextLabels[i+1:]...)
+			break
+		}
+	}
+	// Also clear from grid cells
+	for y := range m.Grid {
+		for x := range m.Grid[y] {
+			if m.Grid[y][x].Text == "" {
+				continue
+			}
+			// Check if this cell belongs to a label
+			found := false
+			for _, tl := range m.TextLabels {
+				runes := []rune(tl.Text)
+				for i := range runes {
+					if tl.Start.X+i == x && tl.Start.Y == y {
+						found = true
+						break
+					}
+				}
+				if found {
+					break
+				}
+			}
+			if !found {
+				m.Grid[y][x].Text = ""
+			}
+		}
+	}
+}
+
+// FindTextLabelAt returns the label index that covers point p, or -1.
+func FindTextLabelAt(m *Map, p Point) int {
+	for i, tl := range m.TextLabels {
+		runes := []rune(tl.Text)
+		for j := range runes {
+			if tl.Start.X+j == p.X && tl.Start.Y == p.Y {
+				return i
+			}
+		}
+	}
+	return -1
+}
+
+// MoveTextLabel moves label at oldStart to newStart.
+func MoveTextLabel(m *Map, oldStart, newStart Point) {
+	for i, tl := range m.TextLabels {
+		if tl.Start == oldStart {
+			// Clear old cells
+			for _, p := range LabelPositions(tl) {
+				if m.InBounds(p) {
+					m.Grid[p.Y][p.X].Text = ""
+				}
+			}
+			m.TextLabels[i].Start = newStart
+			// Set new cells
+			runes := []rune(tl.Text)
+			for j, r := range runes {
+				p := Point{newStart.X + j, newStart.Y}
+				if m.InBounds(p) {
+					m.Grid[p.Y][p.X].Text = string(r)
+				}
+			}
+			return
+		}
+	}
+}
+
+func LabelPositions(tl TextLabel) []Point {
+	var pts []Point
+	runes := []rune(tl.Text)
+	for i := range runes {
+		pts = append(pts, Point{tl.Start.X + i, tl.Start.Y})
+	}
+	return pts
+}
+
+func DemoTools() {
+	m := NewMap("test", 10, 10, nil)
+	Brush(m, Point{5, 5}, 0, 3, nil)
+	if m.Grid[5][5].Terrain != 0 {
+		panic("Brush failed")
+	}
+	pts := BresenhamLine(Point{0, 0}, Point{3, 0})
+	if len(pts) != 4 || pts[0] != (Point{0, 0}) || pts[3] != (Point{3, 0}) {
+		panic(fmt.Sprintf("Line failed: %v", pts))
+	}
+	// intSqrt sanity
+	if intSqrt(25) != 5 || intSqrt(26) != 5 || intSqrt(0) != 0 {
+		panic("intSqrt failed")
+	}
+	// Color picking
+	t := Terrain{Colors: []TerrainColor{{Color: "22", Weight: 100}}}
+	if t.PickColor() != "22" {
+		panic("PickColor failed")
+	}
+	// Text labels — Grid[y][x]
+	PlaceTextLabel(m, Point{2, 2}, "ABC", "")
+	if m.Grid[2][2].Text != "A" || m.Grid[2][3].Text != "B" {
+		panic("TextLabel: " + m.Grid[2][2].Text + "," + m.Grid[2][3].Text)
+	}
+	RemoveTextLabel(m, Point{2, 2})
+	if m.Grid[2][2].Text != "" {
+		panic("TextLabel remove failed")
+	}
+	fmt.Println("tools: ok")
+}
+
+
-- 
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