bring in HarfbuzzShaper into code as a function so we can modify it.

utils.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"hash/maphash"
 	"html"
 	"html/template"
 	"math/rand"
@@ -12,6 +13,7 @@ import (
 	"regexp"
 	"strings"
 	"time"
+	"unsafe"
 
 	"github.com/microcosm-cc/bluemonday"
 	"golang.org/x/exp/slices"
@@ -516,3 +518,18 @@ func maxIndex(slice []int) int {
 	}
 	return maxIndex
 }
+
+// clamp ensures val is in the inclusive range [low,high].
+func clamp(val, low, high int) int {
+	if val < low {
+		return low
+	}
+	if val > high {
+		return high
+	}
+	return val
+}
+
+func pointerHasher[V any](_ maphash.Seed, k *V) uint64 {
+	return uint64(uintptr(unsafe.Pointer(k)))
+}