Fix scaling issues in html module

src/modules/html.js

@@ -320,11 +320,16 @@ import { globalObject } from "../libs/globalObject.js";
         position: "relative",
         display: "inline-block",
         width:
-          Math.max(
-            this.prop.src.clientWidth,
-            this.prop.src.scrollWidth,
-            this.prop.src.offsetWidth
-          ) + "px",
+          (typeof this.opt.width === "number" &&
+          !isNaN(this.opt.width) &&
+          typeof this.opt.windowWidth === "number" &&
+          !isNaN(this.opt.windowWidth)
+            ? this.opt.windowWidth
+            : Math.max(
+                this.prop.src.clientWidth,
+                this.prop.src.scrollWidth,
+                this.prop.src.offsetWidth
+              )) + "px",
         left: 0,
         right: 0,
         top: 0,
@@ -429,11 +434,20 @@ import { globalObject } from "../libs/globalObject.js";
 
         var pdf = this.opt.jsPDF;
         var fontFaces = this.opt.fontFaces;
+
+        var scale =
+          typeof this.opt.width === "number" &&
+          !isNaN(this.opt.width) &&
+          typeof this.opt.windowWidth === "number" &&
+          !isNaN(this.opt.windowWidth)
+            ? this.opt.width / this.opt.windowWidth
+            : 1;
+
         var options = Object.assign(
           {
             async: true,
             allowTaint: true,
-            scale: 1,
+            scale: scale,
             scrollX: this.opt.scrollX || 0,
             scrollY: this.opt.scrollY || 0,
             backgroundColor: "#ffffff",
@@ -1011,8 +1025,14 @@ import { globalObject } from "../libs/globalObject.js";
    * @param {Html2CanvasOptions} [options.html2canvas] html2canvas options
    * @param {FontFace[]} [options.fontFaces] A list of font-faces to match when resolving fonts. Fonts will be added to the PDF based on the specified URL. If omitted, the font match algorithm falls back to old algorithm.
    * @param {jsPDF} [options.jsPDF] jsPDF instance
-   * @param {number} [options.x] x position on the PDF document
-   * @param {number} [options.y] y position on the PDF document
+   * @param {number=} [options.x] x position on the PDF document in jsPDF units.
+   * @param {number=} [options.y] y position on the PDF document in jsPDF units.
+   * @param {number=} [options.width] The target width in the PDF document in jsPDF units. The rendered element will be
+   * scaled such that it fits into the specified width. Has no effect if either the <code>html2canvas.scale<code> is
+   * specified or the <code>windowWidth</code> option is NOT specified.
+   * @param {number=} [options.windowWidth] The window width in CSS pixels. In contrast to the
+   * <code>html2canvas.windowWidth</code> option, this option affects the actual container size while rendering and
+   * does NOT affect CSS media queries. This option only has an effect, if the <code>width<code> option is also specified.
    *
    * @example
    * var doc = new jsPDF();

test/specs/README.md

@@ -20,7 +20,7 @@ If a reference PDF doesn't exist it will be created if you run this command
 while the tests run:
 
 ```
-node tests/utils/reference-server.js
+node test/utils/reference-server.js
 ```
 
 This generates and collects reference PDFs from real browsers. This should be

test/specs/html.spec.js

@@ -27,7 +27,7 @@ function toFontFaceRule(fontFace) {
   `;
 }
 
-describe("Module: html", function() {
+describe("Module: html", () => {
   if (
     (typeof isNode != "undefined" && isNode) ||
     navigator.userAgent.indexOf("Chrome") < 0
@@ -41,6 +41,89 @@ describe("Module: html", function() {
     comparePdf(doc.output(), "html-basic.pdf", "html");
   });
 
+  it("respects width and windowWidth options", async () => {
+    const markup =
+      "<div>" +
+      "Lorem ipsum dolor sit amet consectetur adipisicing elit. Eveniet reprehenderit nihil natus magnam doloremque voluptate ab, laborum officiis corrupti eius voluptatibus quisquam illum esse corporis quod fugit quibusdam minima provident." +
+      "</div>";
+
+    const doc210$250 = await render(markup, { width: 210, windowWidth: 250 });
+    comparePdf(
+      doc210$250.output(),
+      "html-width-210-windowWidth-250.pdf",
+      "html"
+    );
+
+    const doc210$500 = await render(markup, { width: 210, windowWidth: 500 });
+    comparePdf(
+      doc210$500.output(),
+      "html-width-210-windowWidth-500.pdf",
+      "html"
+    );
+
+    const doc210$1000 = await render(markup, { width: 210, windowWidth: 1000 });
+    comparePdf(
+      doc210$1000.output(),
+      "html-width-210-windowWidth-1000.pdf",
+      "html"
+    );
+
+    const doc100$500 = await render(markup, { width: 100, windowWidth: 500 });
+    comparePdf(
+      doc100$500.output(),
+      "html-width-100-windowWidth-500.pdf",
+      "html"
+    );
+
+    const doc300$500 = await render(markup, { width: 300, windowWidth: 500 });
+    comparePdf(
+      doc300$500.output(),
+      "html-width-300-windowWidth-500.pdf",
+      "html"
+    );
+  });
+
+  it("width should not overwrite user-provided html2canvas.scale option", async () => {
+    const markup =
+      "<div>" +
+      "Lorem ipsum dolor sit amet consectetur adipisicing elit. Eveniet reprehenderit nihil natus magnam doloremque voluptate ab, laborum officiis corrupti eius voluptatibus quisquam illum esse corporis quod fugit quibusdam minima provident." +
+      "</div>";
+    const doc = await render(markup, {
+      width: 300,
+      windowWidth: 500,
+      html2canvas: { scale: 2 }
+    });
+    comparePdf(
+      doc.output(),
+      "html-width-300-windowWidth-500-scale-2.pdf",
+      "html"
+    );
+  });
+
+  it("width and windowWidth should only have an effect if both are supplied", async () => {
+    const markup =
+      "<div>" +
+      "Lorem ipsum dolor sit amet consectetur adipisicing elit. Eveniet reprehenderit nihil natus magnam doloremque voluptate ab, laborum officiis corrupti eius voluptatibus quisquam illum esse corporis quod fugit quibusdam minima provident." +
+      "</div>";
+    const docWidthOnly = await render(markup, {
+      width: 300
+    });
+    comparePdf(
+      docWidthOnly.output(),
+      "html-width-default-windowWidth-default.pdf",
+      "html"
+    );
+
+    const docWindowWidthOnly = await render(markup, {
+      windowWidth: 500
+    });
+    comparePdf(
+      docWindowWidthOnly.output(),
+      "html-width-default-windowWidth-default.pdf",
+      "html"
+    );
+  });
+
   it("renders font-faces", async () => {
     const opts = {
       fontFaces: [

types/index.d.ts

@@ -229,6 +229,8 @@ declare module "jspdf" {
     jsPDF?: jsPDF;
     x?: number;
     y?: number;
+    width?: number;
+    windowWidth?: number;
     fontFaces?: HTMLFontFace[];
   }