Add support to scale text horizontally

inspired by #445

Author: liborm85

CHANGELOG.md

@@ -5,6 +5,7 @@
 - Update fontkit to 2.0
 - Update linebreak to 1.1
 - Add support for spot colors
+- Add support to scale text horizontally
 - Fix sets tab order to "Structure" when a document is tagged
 - Fix font cache collision for fonts with missing postscript name or bad TTF metadata
 - Fix measuring text when OpenType features are passed in to .text()

docs/text.md

@@ -94,6 +94,7 @@ below.
 * `lineGap` - the amount of space between each line of text
 * `wordSpacing` - the amount of space between each word in the text
 * `characterSpacing` - the amount of space between each character in the text
+* `horizontalScaling` - ability to scale text horizontally (`100` percent by default)
 * `fill` - whether to fill the text (`true` by default)
 * `stroke` - whether to stroke the text
 * `link` - a URL to link this text to (shortcut to create an annotation)

examples/kitchen-sink.js

@@ -118,4 +118,36 @@ doc.moveDown()
     .fillColor('PANTONE185C')
     .text('This text uses spot color!');
 
+doc.moveDown();
+
+doc
+  .font('Helvetica')
+  .fillColor('#000')
+  .text('Horizontal scaling support:');
+
+doc.moveDown();
+
+doc
+  .text(loremIpsum, {
+    height: 100,
+    width: 300,
+    align: 'justify',
+  });
+
+doc
+  .text(loremIpsum, {
+    height: 100,
+    width: 300,
+    align: 'justify',
+    horizontalScaling: 75
+  });
+
+doc
+  .text(loremIpsum, {
+    height: 100,
+    width: 300,
+    align: 'justify',
+    horizontalScaling: 130
+  });
+
 doc.end();

examples/kitchen-sink.pdf

@@ -8,13 +8,13 @@ class LineWrapper extends EventEmitter {
   constructor(document, options) {
     super();
     this.document = document;
-    this.indent = options.indent || 0;
-    this.characterSpacing = options.characterSpacing || 0;
-    this.wordSpacing = options.wordSpacing === 0;
+    this.horizontalScaling = options.horizontalScaling || 100;
+    this.indent = ((options.indent || 0) * this.horizontalScaling) / 100;
+    this.characterSpacing = ((options.characterSpacing || 0) * this.horizontalScaling) / 100;
+    this.wordSpacing = ((options.wordSpacing === 0) * this.horizontalScaling) / 100;
     this.columns = options.columns || 1;
-    this.columnGap = options.columnGap != null ? options.columnGap : 18; // 1/4 inch
-    this.lineWidth =
-      (options.width - this.columnGap * (this.columns - 1)) / this.columns;
+    this.columnGap = ((options.columnGap != null ? options.columnGap : 18) * this.horizontalScaling) / 100; // 1/4 inch
+    this.lineWidth = (((options.width * this.horizontalScaling) / 100) - (this.columnGap * (this.columns - 1))) / this.columns;
     this.spaceLeft = this.lineWidth;
     this.startX = this.document.x;
     this.startY = this.document.y;
@@ -165,14 +165,15 @@ class LineWrapper extends EventEmitter {
 
   wrap(text, options) {
     // override options from previous continued fragments
+    this.horizontalScaling = options.horizontalScaling || 100;
     if (options.indent != null) {
-      this.indent = options.indent;
+      this.indent = (options.indent * this.horizontalScaling) / 100;
     }
     if (options.characterSpacing != null) {
-      this.characterSpacing = options.characterSpacing;
+      this.characterSpacing = (options.characterSpacing * this.horizontalScaling) / 100;
     }
     if (options.wordSpacing != null) {
-      this.wordSpacing = options.wordSpacing;
+      this.wordSpacing = (options.wordSpacing * this.horizontalScaling) / 100;
     }
     if (options.ellipsis != null) {
       this.ellipsis = options.ellipsis;

lib/line_wrapper.js

@@ -47,7 +47,7 @@ export default {
     const addStructure = () => {
       if (options.structParent) {
         options.structParent.add(this.struct(options.structType || 'P',
-          [ this.markStructureContent(options.structType || 'P') ]));
+          [this.markStructureContent(options.structType || 'P')]));
       }
     };
 
@@ -80,10 +80,8 @@ export default {
   },
 
   widthOfString(string, options = {}) {
-    return (
-      this._font.widthOfString(string, this._fontSize, options.features) +
-      (options.characterSpacing || 0) * (string.length - 1)
-    );
+    const horizontalScaling = options.horizontalScaling || 100;
+    return ((this._font.widthOfString(string, this._fontSize, options.features) + (options.characterSpacing || 0) * (string.length - 1)) * horizontalScaling) / 100;
   },
 
   heightOfString(text, options) {
@@ -121,7 +119,7 @@ export default {
     const levels = [];
     const numbers = [];
 
-    var flatten = function(list) {
+    var flatten = function (list) {
       let n = 1;
       for (let i = 0; i < list.length; i++) {
         const item = list[i];
@@ -141,7 +139,7 @@ export default {
 
     flatten(list);
 
-    const label = function(n) {
+    const label = function (n) {
       switch (listType) {
         case 'numbered':
           return `${n}.`;
@@ -153,7 +151,7 @@ export default {
       }
     };
 
-    const drawListItem = function(listItem, i) {
+    const drawListItem = function (listItem, i) {
       wrapper = new LineWrapper(this, options);
       wrapper.on('line', this._line);
 
@@ -299,6 +297,7 @@ export default {
     const align = options.align || 'left';
     let wordSpacing = options.wordSpacing || 0;
     const characterSpacing = options.characterSpacing || 0;
+    const horizontalScaling = options.horizontalScaling || 100;
 
     // text alignments
     if (options.width) {
@@ -320,7 +319,7 @@ export default {
           wordSpacing = Math.max(
             0,
             (options.lineWidth - textWidth) / Math.max(1, words.length - 1) -
-              spaceWidth
+            spaceWidth
           );
           break;
       }
@@ -388,13 +387,13 @@ export default {
         this._fontSize < 10 ? 0.5 : Math.floor(this._fontSize / 10);
       this.lineWidth(lineWidth);
 
-      let lineY = (y + this.currentLineHeight())  - lineWidth
+      let lineY = (y + this.currentLineHeight()) - lineWidth
       this.moveTo(x, lineY);
       this.lineTo(x + renderedWidth, lineY);
       this.stroke();
       this.restore();
     }
-    
+
     // create strikethrough line
     if (options.strike) {
       this.save();
@@ -457,6 +456,11 @@ export default {
       this.addContent(`${number(characterSpacing)} Tc`);
     }
 
+    // Horizontal scaling
+    if (horizontalScaling !== 100) {
+      this.addContent(`${horizontalScaling} Tz`);
+    }
+
     // Add the actual text
     // If we have a word spacing value, we need to encode each word separately
     // since the normal Tw operator only works on character code 32, which isn't