diff --git a/external/qcms/qcms.js b/external/qcms/qcms.js
index 3995a18e3..b19a5da83 100644
--- a/external/qcms/qcms.js
+++ b/external/qcms/qcms.js
@@ -1,5 +1,5 @@
 /* THIS FILE IS GENERATED - DO NOT EDIT */
-import { copy_result, copy_rgb } from './qcms_utils.js';
+import { copy_result, copy_rgb, make_cssRGB } from './qcms_utils.js';
 
 let wasm;
 
@@ -48,9 +48,10 @@ export function qcms_convert_array(transformer, src) {
  * This function is called directly from JavaScript.
  * @param {number} transformer
  * @param {number} src
+ * @param {boolean} css
  */
-export function qcms_convert_one(transformer, src) {
-    wasm.qcms_convert_one(transformer, src);
+export function qcms_convert_one(transformer, src, css) {
+    wasm.qcms_convert_one(transformer, src, css);
 }
 
 /**
@@ -61,9 +62,10 @@ export function qcms_convert_one(transformer, src) {
  * @param {number} src1
  * @param {number} src2
  * @param {number} src3
+ * @param {boolean} css
  */
-export function qcms_convert_three(transformer, src1, src2, src3) {
-    wasm.qcms_convert_three(transformer, src1, src2, src3);
+export function qcms_convert_three(transformer, src1, src2, src3, css) {
+    wasm.qcms_convert_three(transformer, src1, src2, src3, css);
 }
 
 /**
@@ -75,9 +77,10 @@ export function qcms_convert_three(transformer, src1, src2, src3) {
  * @param {number} src2
  * @param {number} src3
  * @param {number} src4
+ * @param {boolean} css
  */
-export function qcms_convert_four(transformer, src1, src2, src3, src4) {
-    wasm.qcms_convert_four(transformer, src1, src2, src3, src4);
+export function qcms_convert_four(transformer, src1, src2, src3, src4, css) {
+    wasm.qcms_convert_four(transformer, src1, src2, src3, src4, css);
 }
 
 /**
@@ -167,6 +170,9 @@ function __wbg_get_imports() {
     imports.wbg.__wbg_copyrgb_d60ce17bb05d9b67 = function(arg0) {
         copy_rgb(arg0 >>> 0);
     };
+    imports.wbg.__wbg_makecssRGB_893bf0cd9fdb302d = function(arg0) {
+        make_cssRGB(arg0 >>> 0);
+    };
     imports.wbg.__wbindgen_init_externref_table = function() {
         const table = wasm.__wbindgen_export_0;
         const offset = table.grow(4);
diff --git a/external/qcms/qcms_bg.wasm b/external/qcms/qcms_bg.wasm
index aa8be2c29..6ed10d710 100644
Binary files a/external/qcms/qcms_bg.wasm and b/external/qcms/qcms_bg.wasm differ
diff --git a/external/qcms/qcms_utils.js b/external/qcms/qcms_utils.js
index f0b6e679d..11d35351e 100644
--- a/external/qcms/qcms_utils.js
+++ b/external/qcms/qcms_utils.js
@@ -14,41 +14,71 @@
  */
 
 class QCMS {
-  static _module = null;
+  static #memoryArray = null;
+
+  static _memory = null;
 
   static _mustAddAlpha = false;
 
   static _destBuffer = null;
+
+  static _destOffset = 0;
+
+  static _destLength = 0;
+
+  static _cssColor = "";
+
+  static _makeHexColor = null;
+
+  static get _memoryArray() {
+    const array = this.#memoryArray;
+    if (array?.byteLength) {
+      return array;
+    }
+    return (this.#memoryArray = new Uint8Array(this._memory.buffer));
+  }
 }
 
 function copy_result(ptr, len) {
   // This function is called from the wasm module (it's an external
   // "C" function). Its goal is to copy the result from the wasm memory
   // to the destination buffer without any intermediate copies.
-  const { _module, _mustAddAlpha, _destBuffer } = QCMS;
-  const result = new Uint8Array(_module.memory.buffer, ptr, len);
-  if (result.length === _destBuffer.length) {
-    _destBuffer.set(result);
+  const { _mustAddAlpha, _destBuffer, _destOffset, _destLength, _memoryArray } =
+    QCMS;
+  if (len === _destLength) {
+    _destBuffer.set(_memoryArray.subarray(ptr, ptr + len), _destOffset);
     return;
   }
   if (_mustAddAlpha) {
-    for (let i = 0, j = 0, ii = result.length; i < ii; i += 3, j += 4) {
-      _destBuffer[j] = result[i];
-      _destBuffer[j + 1] = result[i + 1];
-      _destBuffer[j + 2] = result[i + 2];
+    for (let i = ptr, ii = ptr + len, j = _destOffset; i < ii; i += 3, j += 4) {
+      _destBuffer[j] = _memoryArray[i];
+      _destBuffer[j + 1] = _memoryArray[i + 1];
+      _destBuffer[j + 2] = _memoryArray[i + 2];
       _destBuffer[j + 3] = 255;
     }
   } else {
-    for (let i = 0, j = 0, ii = result.length; i < ii; i += 3, j += 4) {
-      _destBuffer[j] = result[i];
-      _destBuffer[j + 1] = result[i + 1];
-      _destBuffer[j + 2] = result[i + 2];
+    for (let i = ptr, ii = ptr + len, j = _destOffset; i < ii; i += 3, j += 4) {
+      _destBuffer[j] = _memoryArray[i];
+      _destBuffer[j + 1] = _memoryArray[i + 1];
+      _destBuffer[j + 2] = _memoryArray[i + 2];
     }
   }
 }
 
 function copy_rgb(ptr) {
-  QCMS._destBuffer.set(new Uint8Array(QCMS._module.memory.buffer, ptr, 3));
+  const { _destBuffer, _destOffset, _memoryArray } = QCMS;
+  _destBuffer[_destOffset] = _memoryArray[ptr];
+  _destBuffer[_destOffset + 1] = _memoryArray[ptr + 1];
+  _destBuffer[_destOffset + 2] = _memoryArray[ptr + 2];
 }
 
-export { copy_result, copy_rgb, QCMS };
+function make_cssRGB(ptr) {
+  const { _memoryArray } = QCMS;
+  QCMS._cssColor = QCMS._makeHexColor(
+    _memoryArray[ptr],
+    _memoryArray[ptr + 1],
+    _memoryArray[ptr + 2]
+  );
+}
+
+export { copy_result, copy_rgb, make_cssRGB, QCMS };
diff --git a/src/core/icc_colorspace.js b/src/core/icc_colorspace.js
index d955e3da0..b8ed91a6f 100644
--- a/src/core/icc_colorspace.js
+++ b/src/core/icc_colorspace.js
@@ -24,7 +24,7 @@ import {
   qcms_drop_transformer,
   qcms_transformer_from_memory,
 } from "../../external/qcms/qcms.js";
-import { shadow, warn } from "../shared/util.js";
+import { shadow, Util, warn } from "../shared/util.js";
 import { ColorSpace } from "./colorspace.js";
 import { QCMS } from "../../external/qcms/qcms_utils.js";
 
@@ -63,28 +63,30 @@ class IccColorSpace extends ColorSpace {
     switch (numComps) {
       case 1:
         inType = DataType.Gray8;
-        this.#convertPixel = (src, srcOffset) =>
-          qcms_convert_one(this.#transformer, src[srcOffset] * 255);
+        this.#convertPixel = (src, srcOffset, css) =>
+          qcms_convert_one(this.#transformer, src[srcOffset] * 255, css);
         break;
       case 3:
         inType = DataType.RGB8;
-        this.#convertPixel = (src, srcOffset) =>
+        this.#convertPixel = (src, srcOffset, css) =>
           qcms_convert_three(
             this.#transformer,
             src[srcOffset] * 255,
             src[srcOffset + 1] * 255,
-            src[srcOffset + 2] * 255
+            src[srcOffset + 2] * 255,
+            css
           );
         break;
       case 4:
         inType = DataType.CMYK;
-        this.#convertPixel = (src, srcOffset) =>
+        this.#convertPixel = (src, srcOffset, css) =>
           qcms_convert_four(
             this.#transformer,
             src[srcOffset] * 255,
             src[srcOffset + 1] * 255,
             src[srcOffset + 2] * 255,
-            src[srcOffset + 3] * 255
+            src[srcOffset + 3] * 255,
+            css
           );
         break;
       default:
@@ -101,9 +103,16 @@ class IccColorSpace extends ColorSpace {
     IccColorSpace.#finalizer.register(this, this.#transformer);
   }
 
+  getRgbHex(src, srcOffset) {
+    this.#convertPixel(src, srcOffset, /* css */ true);
+    return QCMS._cssColor;
+  }
+
   getRgbItem(src, srcOffset, dest, destOffset) {
-    QCMS._destBuffer = dest.subarray(destOffset, destOffset + 3);
-    this.#convertPixel(src, srcOffset);
+    QCMS._destBuffer = dest;
+    QCMS._destOffset = destOffset;
+    QCMS._destLength = 3;
+    this.#convertPixel(src, srcOffset, /* css */ false);
     QCMS._destBuffer = null;
   }
 
@@ -116,10 +125,9 @@ class IccColorSpace extends ColorSpace {
       }
     }
     QCMS._mustAddAlpha = alpha01 && dest.buffer === src.buffer;
-    QCMS._destBuffer = dest.subarray(
-      destOffset,
-      destOffset + count * (3 + alpha01)
-    );
+    QCMS._destBuffer = dest;
+    QCMS._destOffset = destOffset;
+    QCMS._destLength = count * (3 + alpha01);
     qcms_convert_array(this.#transformer, src);
     QCMS._mustAddAlpha = false;
     QCMS._destBuffer = null;
@@ -143,10 +151,12 @@ class IccColorSpace extends ColorSpace {
     if (this.#useWasm) {
       if (this.#wasmUrl) {
         try {
-          this._module = QCMS._module = initSync({
+          this._module = initSync({
             module: fetchSync(`${this.#wasmUrl}qcms_bg.wasm`),
           });
           isUsable = !!this._module;
+          QCMS._memory = this._module.memory;
+          QCMS._makeHexColor = Util.makeHexColor;
         } catch (e) {
           warn(`ICCBased color space: "${e}".`);
         }