Clean up jsPDF override code

andrewcmyers · Apr 20, 2021 · 108a4f0 · 108a4f0
1 parent 6f85788
commit 108a4f0
Showing 1 changed file with 24 additions and 23 deletions.
diff --git a/constrain-pdf.js b/constrain-pdf.js
@@ -252,46 +252,46 @@ function override_jsPDF(jspdf, ctx, figure) {
     const prototype = jspdf.context2d.constructor.prototype,
         Point = jspdf.internal.Point
 
+    // Allow recognizing special contexts
     prototype.printMedia = true
 
+    // setLineDash() is not implemented by jsPDF.Context2d
     prototype.setLineDash = function(pattern) {
         this.ctx.lineDash = pattern
         jspdf.setLineDashPattern(pattern.map(x => x * figure.scale))
     }
+    // getLineDash() is not implemented by jsPDF.context2d
     prototype.getLineDash = function() {
         const r = this.ctx.lineDash
         if (!r) return []
         if (r.length % 2 == 0) return r
         else return r.concat(r)
     }
+    // Need to use original context to make text measurements correct
     prototype.measureText = function(s) {
         ctx.font = this.font
         return ctx.measureText(s)
     }
-  prototype.closePath = function() {
-    let pathBegin = new Point(0, 0);
-    let i = 0;
-    for (i = this.path.length - 1; i !== -1; i--) {
-      if (this.path[i].type === "begin") {
-        if (
-          typeof this.path[i + 1] === "object" &&
-          typeof this.path[i + 1].x === "number"
-        ) {
-          pathBegin = new Point(this.path[i + 1].x, this.path[i + 1].y);
-          this.path.push({
-            type: "lt",
-            x: pathBegin.x,
-            y: pathBegin.y
-          });
-          break;
+    // Remove extra path segment that Context2d.closePath() adds for
+    // some reason.
+    prototype.closePath = function() {
+        let pathBegin = new Point(0, 0)
+        for (let i = this.path.length - 1; i >= 0; i--) {
+        if (this.path[i].type === "begin") {
+            if (typeof this.path[i + 1] === "object" && typeof this.path[i + 1].x === "number") {
+                pathBegin = new Point(this.path[i + 1].x, this.path[i + 1].y)
+                this.path.push({
+                    type: "lt",
+                    x: pathBegin.x,
+                    y: pathBegin.y
+                })
+                break
+            }
         }
-      }
+        }
+        this.path.push({ type: "close" })
+        this.ctx.lastPoint = new Point(pathBegin.x, pathBegin.y)
     }
-    this.path.push({
-      type: "close"
-    });
-    this.ctx.lastPoint = new Point(pathBegin.x, pathBegin.y);
-  }
 }
 
 class PrintJob {
@@ -312,9 +312,10 @@ class PrintJob {
         const figure = this.figure
         const save_ctx = figure.ctx
         const orientation = (figure.width > figure.height) ? "l" : "p"
+        const unit = "px"
         const output = new jspdf.jsPDF({
                orientation,
-               unit: "px",
+               unit,
                format: [figure.width * figure.scale, figure.height * figure.scale],
                hot_fixes: ["px_scaling"]
             })