fix for lines (stroke) are rendered too thick (Bug 1743245)

This commit fixes Bug 1743245 (Grided PDF file lines rendered too thick) which was created by a fix for  #12868 .
The lineWidth was set to round(1 * this._combinedScaleFactor) when the pixel is drawn as a parallelorgam with a height <1. This fix changes this to floor(1*this._combinedScaleFactor) .

This change shows a visual result comparable to Chrome and Acrobat.
Regarding the last PR 3 statements in canvas.js are affected and will change with this commit (stroke and paintChar).

renaming the reference files to naming comvention

src/display/canvas.js

@@ -1770,7 +1770,7 @@ class CanvasGraphics {
           // parallelogram where both heights are lower than 1 and not equal.
           ctx.save();
           ctx.resetTransform();
-          ctx.lineWidth = Math.round(this._combinedScaleFactor);
+          ctx.lineWidth = Math.floor(this._combinedScaleFactor);
           ctx.stroke();
           ctx.restore();
         } else {
@@ -2040,7 +2040,7 @@ class CanvasGraphics {
       ) {
         if (resetLineWidthToOne) {
           ctx.resetTransform();
-          ctx.lineWidth = Math.round(this._combinedScaleFactor);
+          ctx.lineWidth = Math.floor(this._combinedScaleFactor);
         }
         ctx.stroke();
       }
@@ -2060,7 +2060,7 @@ class CanvasGraphics {
           ctx.save();
           ctx.moveTo(x, y);
           ctx.resetTransform();
-          ctx.lineWidth = Math.round(this._combinedScaleFactor);
+          ctx.lineWidth = Math.floor(this._combinedScaleFactor);
           ctx.strokeText(character, 0, 0);
           ctx.restore();
         } else {

test/pdfs/.gitignore

@@ -471,6 +471,7 @@
 !issue11442_reduced.pdf
 !issue11549_reduced.pdf
 !issue8097_reduced.pdf
+!bug1743245.pdf
 !quadpoints.pdf
 !transparent.pdf
 !issue13931.pdf

test/test_manifest.json

@@ -4042,6 +4042,12 @@
        "type": "eq",
        "annotations": true
     },
+    {  "id": "bug1743245",
+       "file": "pdfs/bug1743245.pdf",
+       "md5": "01eadf118ec05fe02e91db63536d50f6",
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "issue1002",
       "file": "pdfs/issue1002.pdf",
       "md5": "af62d6cd95079322d4af18edd960d15c",