Implement rendering line annotations without appearance stream

src/core/annotation.js

@@ -2280,9 +2280,34 @@ class LineAnnotation extends MarkupAnnotation {
 
     this.data.annotationType = AnnotationType.LINE;
 
-    this.data.lineCoordinates = Util.normalizeRect(
-      parameters.dict.getArray("L")
-    );
+    const lineCoordinates = parameters.dict.getArray("L");
+    this.data.lineCoordinates = Util.normalizeRect(lineCoordinates);
+
+    if (!this.appearance) {
+      // The default stroke color is black.
+      const strokeColor = this.color
+        ? Array.from(this.color).map(c => c / 255)
+        : [0, 0, 0];
+
+      const borderWidth = this.borderStyle.width;
+
+      this._setDefaultAppearance({
+        xref: parameters.xref,
+        extra: `${borderWidth} w`,
+        strokeColor,
+        pointsCallback: (buffer, points) => {
+          buffer.push(`${lineCoordinates[0]} ${lineCoordinates[1]} m`);
+          buffer.push(`${lineCoordinates[2]} ${lineCoordinates[3]} l`);
+          buffer.push("S");
+          return [
+            points[0].x - borderWidth,
+            points[1].x + borderWidth,
+            points[3].y - borderWidth,
+            points[1].y + borderWidth,
+          ];
+        },
+      });
+    }
   }
 }
 

test/pdfs/.gitignore

@@ -393,6 +393,7 @@
 !issue12418_reduced.pdf
 !annotation-freetext.pdf
 !annotation-line.pdf
+!annotation-line-without-appearance.pdf
 !bug1669099.pdf
 !annotation-square-circle.pdf
 !annotation-square-circle-without-appearance.pdf

test/test_manifest.json

@@ -4717,6 +4717,13 @@
        "type": "eq",
        "annotations": true
     },
+    {  "id": "annotation-line-without-appearance",
+       "file": "pdfs/annotation-line-without-appearance.pdf",
+       "md5": "1f60935b2a7719ce40616af60fc308a2",
+       "rounds": 1,
+       "annotations": true,
+       "type": "eq"
+    },
     {  "id": "annotation-square-circle",
        "file": "pdfs/annotation-square-circle.pdf",
        "md5": "cfd3c302f68d61e1d55ed9c7896046c3",