Add algorithm for figuring out the recommended height of text

recommend.go

@@ -0,0 +1,37 @@
+package typeset
+
+import "golang.org/x/image/font"
+import "golang.org/x/image/math/fixed"
+
+func recommendHeight (tokens []token, face font.Face, width fixed.Int26_6) fixed.Int26_6 {	
+	metrics := face.Metrics()
+	var dot fixed.Point26_6
+
+	newline := func () {
+		dot.Y  += metrics.Height
+		dot.X   = 0
+	}
+
+	sawLineBreak := false
+	for _, token := range tokens {
+		// demarcate lines
+		if sawLineBreak {
+			newline()
+			sawLineBreak = false
+		}
+		if token.kind == tokenKindLineBreak {
+			sawLineBreak = true
+		} else {
+			needWrap :=
+				token.kind == tokenKindWord &&
+				dot.X + token.width > width
+			if needWrap {
+				newline()
+			}
+			dot.X += token.width
+		}
+	}
+	newline()
+	
+	return dot.Y
+}