Move rotation normalization from PDFViewerApplication and into BaseViewer

src/display/display_utils.js

@@ -250,8 +250,11 @@ class PageViewport {
     const centerX = (viewBox[2] + viewBox[0]) / 2;
     const centerY = (viewBox[3] + viewBox[1]) / 2;
     let rotateA, rotateB, rotateC, rotateD;
-    rotation = rotation % 360;
-    rotation = rotation < 0 ? rotation + 360 : rotation;
+    // Normalize the rotation, by clamping it to the [0, 360) range.
+    rotation %= 360;
+    if (rotation < 0) {
+      rotation += 360;
+    }
     switch (rotation) {
       case 180:
         rotateA = -1;

web/app.js

@@ -1856,11 +1856,7 @@ const PDFViewerApplication = {
   },
 
   rotatePages(delta) {
-    if (!this.pdfDocument) {
-      return;
-    }
-    const newRotation = (this.pdfViewer.pagesRotation + 360 + delta) % 360;
-    this.pdfViewer.pagesRotation = newRotation;
+    this.pdfViewer.pagesRotation += delta;
     // Note that the thumbnail viewer is updated, and rendering is triggered,
     // in the 'rotationchanging' event handler.
   },

web/base_viewer.js

@@ -388,6 +388,11 @@ class BaseViewer {
     if (!this.pdfDocument) {
       return;
     }
+    // Normalize the rotation, by clamping it to the [0, 360) range.
+    rotation %= 360;
+    if (rotation < 0) {
+      rotation += 360;
+    }
     if (this._pagesRotation === rotation) {
       return; // The rotation didn't change.
     }