Implement justifying for unicode fonts (#3285)

Co-authored-by: Lukas Holländer <[email protected]>

Author: owenl131

src/jspdf.js

@@ -3806,23 +3806,23 @@ function jsPDF(options) {
     flags = Object.assign({ autoencode: true, noBOM: true }, options.flags);
 
     var wordSpacingPerLine = [];
-
+    var findWidth = function(v) {
+      return (
+        (scope.getStringUnitWidth(v, {
+          font: activeFont,
+          charSpace: charSpace,
+          fontSize: activeFontSize,
+          doKerning: false
+        }) *
+          activeFontSize) /
+        scaleFactor
+      );
+    };
     if (Object.prototype.toString.call(text) === "[object Array]") {
       da = transformTextToSpecialArray(text);
       var newY;
       if (align !== "left") {
-        lineWidths = da.map(function(v) {
-          return (
-            (scope.getStringUnitWidth(v, {
-              font: activeFont,
-              charSpace: charSpace,
-              fontSize: activeFontSize,
-              doKerning: false
-            }) *
-              activeFontSize) /
-            scaleFactor
-          );
-        });
+        lineWidths = da.map(findWidth);
       }
       //The first line uses the "main" Td setting,
       //and the subsequent lines are offset by the
@@ -3869,11 +3869,41 @@ function jsPDF(options) {
         for (var h = 0; h < len; h++) {
           text.push(da[h]);
         }
+      } else if (align === "justify" && activeFont.encoding === "Identity-H") {
+        // when using unicode fonts, wordSpacePerLine does not apply
+        text = [];
+        len = da.length;
+        maxWidth = maxWidth !== 0 ? maxWidth : pageWidth;
+        let backToStartX = 0;
+        for (var l = 0; l < len; l++) {
+          newY = l === 0 ? getVerticalCoordinate(y) : -leading;
+          newX = l === 0 ? getHorizontalCoordinate(x) : backToStartX;
+          if (l < len - 1) {
+            let spacing = scale(
+              (maxWidth - lineWidths[l]) / (da[l].split(" ").length - 1)
+            );
+            let words = da[l].split(" ");
+            text.push([words[0] + " ", newX, newY]);
+            backToStartX = 0; // distance to reset back to the left
+            for (let i = 1; i < words.length; i++) {
+              let shiftAmount =
+                (findWidth(words[i - 1] + " " + words[i]) -
+                  findWidth(words[i])) *
+                  scaleFactor +
+                spacing;
+              if (i == words.length - 1) text.push([words[i], shiftAmount, 0]);
+              else text.push([words[i] + " ", shiftAmount, 0]);
+              backToStartX -= shiftAmount;
+            }
+          } else {
+            text.push([da[l], newX, newY]);
+          }
+        }
+        text.push(["", backToStartX, 0]);
       } else if (align === "justify") {
         text = [];
         len = da.length;
         maxWidth = maxWidth !== 0 ? maxWidth : pageWidth;
-
         for (var l = 0; l < len; l++) {
           newY = l === 0 ? getVerticalCoordinate(y) : -leading;
           newX = l === 0 ? getHorizontalCoordinate(x) : 0;

test/reference/justify-custom-font.pdf

@@ -175,6 +175,25 @@ break`
     comparePdf(doc.output(), "alignment.pdf", "text");
   });
 
+  it("should justify custom font", () => {
+    const doc = jsPDF({ floatPrecision: 2 });
+    var PTSans;
+    if (typeof global === "object" && global.isNode === true) {
+      PTSans = doc.loadFile("./test/reference/PTSans.ttf");
+    } else {
+      PTSans = doc.loadFile("base/test/reference/PTSans.ttf");
+    }
+    doc.addFileToVFS("PTSans.ttf", PTSans);
+    doc.addFont("PTSans.ttf", "PTSans", "normal");
+    doc.setFont("PTSans");
+    doc.setFontSize(10);
+    doc.text("А ну чики брики и в дамки! А ну чики брики и в дамки! А ну чики брики и в дамки! А ну чики брики и в дамки! А ну чики брики и в дамки! А ну чики брики и в дамки! А ну чики брики и в дамки! А ну чики брики и в дамки! А ну чики брики и в дамки! ", 10, 10, {
+      align: "justify",
+      maxWidth: 100,
+    });
+    comparePdf(doc.output(), "justify-custom-font.pdf", "text");
+  });
+
   it("should throw an error if not a string", () => {
     expect(() => {
       const doc = jsPDF({ floatPrecision: 2 });