Add horizontal scale option for text (#3294)

Author: owenl131

src/jspdf.js

@@ -3404,6 +3404,7 @@ function jsPDF(options) {
    * @param {number|Matrix} [options.angle=0] - Rotate the text clockwise or counterclockwise. Expects the angle in degree.
    * @param {number} [options.rotationDirection=1] - Direction of the rotation. 0 = clockwise, 1 = counterclockwise.
    * @param {number} [options.charSpace=0] - The space between each letter.
+   * @param {number} [options.horizontalScale=1] - Horizontal scale of the text as a factor of the regular size.
    * @param {number} [options.lineHeightFactor=1.15] - The lineheight of each line.
    * @param {Object} [options.flags] - Flags for to8bitStream.
    * @param {boolean} [options.flags.noBOM=true] - Don't add BOM to Unicode-text.
@@ -3440,7 +3441,7 @@ function jsPDF(options) {
      */
     options = options || {};
     var scope = options.scope || this;
-    var payload, da, angle, align, charSpace, maxWidth, flags;
+    var payload, da, angle, align, charSpace, maxWidth, flags, horizontalScale;
 
     // Pre-August-2012 the order of arguments was function(x, y, text, flags)
     // in effort to make all calls have similar signature like
@@ -3707,6 +3708,11 @@ function jsPDF(options) {
       this.setCharSpace(this.getCharSpace() || 0);
     }
 
+    horizontalScale = options.horizontalScale;
+    if (typeof horizontalScale !== "undefined") {
+      xtra += hpf(horizontalScale * 100) + " Tz\n";
+    }
+
     //lang
 
     var lang = options.lang;

test/reference/text-horizontal-scaling.pdf

@@ -211,6 +211,15 @@ break`
     comparePdf(doc.output(), "letter-spacing.pdf", "text");
   });
 
+  it("should render horizontally scaled text", () => {
+    const doc = jsPDF({ floatPrecision: 2 });
+    doc.text("hello", 10, 10, { horizontalScale: 0.5 });
+    doc.text("hello", 10, 20, { horizontalScale: 0.75 });
+    doc.text("hello", 10, 30, { horizontalScale: 1 });
+    doc.text("hello", 10, 40, { horizontalScale: 1.5 });
+    comparePdf(doc.output(), "text-horizontal-scaling.pdf", "text");
+  });
+
   it("should respect autoencode and noBOM flags", () => {
     const doc = jsPDF({ floatPrecision: 2 });
 

test/specs/text.spec.js

@@ -549,6 +549,7 @@ declare module "jspdf" {
     };
     rotationDirection?: 0 | 1;
     charSpace?: number;
+    horizontalScale?: number;
     lineHeightFactor?: number;
     maxWidth?: number;
     renderingMode?: