svg-maker: svgc - .svgd text format -> SVG for agent-helm sharing

Line-based DSL (shapes, text, groups, color vars) with strict
validation and line-numbered errors, SVG emitter with visibility
defaults, truecolor terminal preview (same half-block technique as
spritec), info with bbox + outside-canvas warnings. Verified
end-to-end: svgc build -> helmd share -> visible through the hub.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011KikHkfCiC3yELbsMN8fT9

svg-maker/svg/info.go

@@ -0,0 +1,143 @@
+package svg
+
+import (
+	"fmt"
+	"math"
+	"sort"
+	"strings"
+)
+
+// Info summarizes a parsed document: element counts, colors, the
+// drawing's bounding box and warnings (things drawn outside the
+// canvas), so an agent can verify a build without looking at pixels.
+func Info(d *Doc) string {
+	counts := map[string]int{}
+	colors := map[string]bool{}
+	minX, minY := math.Inf(1), math.Inf(1)
+	maxX, maxY := math.Inf(-1), math.Inf(-1)
+	var warnings []string
+
+	var walk func(els []*Elem)
+	walk = func(els []*Elem) {
+		for _, el := range els {
+			if el.Kind == "group" {
+				counts["group"]++
+				walk(el.Kids)
+				continue
+			}
+			counts[el.Kind]++
+			for _, key := range []string{"fill", "stroke"} {
+				if c := el.Attrs[key]; c != "" && c != "none" && c != "transparent" {
+					colors[c] = true
+				}
+			}
+			x0, y0, x1, y1, ok := bbox(el)
+			if !ok {
+				continue
+			}
+			minX = math.Min(minX, x0)
+			minY = math.Min(minY, y0)
+			maxX = math.Max(maxX, x1)
+			maxY = math.Max(maxY, y1)
+			if x1 < 0 || y1 < 0 || x0 > d.W || y0 > d.H {
+				warnings = append(warnings, fmt.Sprintf("line %d: %s is entirely outside the canvas", el.Line, el.Kind))
+			} else if x0 < 0 || y0 < 0 || x1 > d.W || y1 > d.H {
+				warnings = append(warnings, fmt.Sprintf("line %d: %s sticks outside the canvas", el.Line, el.Kind))
+			}
+		}
+	}
+	walk(d.Elems)
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "canvas: %gx%g", d.W, d.H)
+	if d.Bg != "" {
+		fmt.Fprintf(&b, "  bg: %s", d.Bg)
+	}
+	b.WriteString("\n")
+	kinds := make([]string, 0, len(counts))
+	for k := range counts {
+		kinds = append(kinds, k)
+	}
+	sort.Strings(kinds)
+	total := 0
+	parts := make([]string, 0, len(kinds))
+	for _, k := range kinds {
+		parts = append(parts, fmt.Sprintf("%s:%d", k, counts[k]))
+		if k != "group" {
+			total += counts[k]
+		}
+	}
+	fmt.Fprintf(&b, "elements: %d (%s)\n", total, strings.Join(parts, " "))
+	if len(colors) > 0 {
+		cl := make([]string, 0, len(colors))
+		for c := range colors {
+			cl = append(cl, c)
+		}
+		sort.Strings(cl)
+		fmt.Fprintf(&b, "colors: %s\n", strings.Join(cl, " "))
+	}
+	if total > 0 && !math.IsInf(minX, 1) {
+		fmt.Fprintf(&b, "drawing bbox: %.4g,%.4g .. %.4g,%.4g\n", minX, minY, maxX, maxY)
+	}
+	for _, w := range warnings {
+		fmt.Fprintf(&b, "warning: %s\n", w)
+	}
+	return b.String()
+}
+
+// bbox computes an element's geometric bounding box (stroke width and
+// transforms not included — good enough for out-of-canvas warnings).
+func bbox(el *Elem) (x0, y0, x1, y1 float64, ok bool) {
+	switch el.Kind {
+	case "rect":
+		return el.Nums[0], el.Nums[1], el.Nums[0] + el.Nums[2], el.Nums[1] + el.Nums[3], true
+	case "circle":
+		cx, cy, r := el.Nums[0], el.Nums[1], el.Nums[2]
+		return cx - r, cy - r, cx + r, cy + r, true
+	case "ellipse":
+		cx, cy, rx, ry := el.Nums[0], el.Nums[1], el.Nums[2], el.Nums[3]
+		return cx - rx, cy - ry, cx + rx, cy + ry, true
+	case "line":
+		return math.Min(el.Nums[0], el.Nums[2]), math.Min(el.Nums[1], el.Nums[3]),
+			math.Max(el.Nums[0], el.Nums[2]), math.Max(el.Nums[1], el.Nums[3]), true
+	case "polyline", "polygon":
+		return pointsBBox(el.Points)
+	case "path":
+		subs, err := flattenPath(el.D)
+		if err != nil {
+			return 0, 0, 0, 0, false
+		}
+		var all [][2]float64
+		for _, sp := range subs {
+			all = append(all, sp...)
+		}
+		return pointsBBox(all)
+	case "text":
+		size := attrFloat(el.Attrs, "font-size", 16)
+		w := 0.6 * size * float64(len([]rune(el.Text)))
+		x, y := el.Nums[0], el.Nums[1]
+		switch el.Attrs["text-anchor"] {
+		case "middle":
+			x -= w / 2
+		case "end":
+			x -= w
+		}
+		return x, y - size, x + w, y, true
+	}
+	return 0, 0, 0, 0, false
+}
+
+func pointsBBox(pts [][2]float64) (x0, y0, x1, y1 float64, ok bool) {
+	if len(pts) == 0 {
+		return 0, 0, 0, 0, false
+	}
+	x0, y0 = pts[0][0], pts[0][1]
+	x1, y1 = x0, y0
+	for _, p := range pts {
+		x0 = math.Min(x0, p[0])
+		y0 = math.Min(y0, p[1])
+		x1 = math.Max(x1, p[0])
+		y1 = math.Max(y1, p[1])
+	}
+	return x0, y0, x1, y1, true
+}