From 5f8598abb78dcd7bcabbc608b7db01c4cf0ec0a1 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 2 Dec 2022 10:09:35 +0100
Subject: [PATCH] [api-minor] Normalize the `view`-getter on the worker-thread

*Please note:* I don't really expect that this is will be an observable change, since virtually all PDF documents already order e.g. /MediaBox and /CropBox entries correctly.

By normalizing boundingBoxes already on the worker-thread, we can be sure that even a corrupt document won't cause issues.
Note how we're passing the `view`-getter to the `PartialEvaluator.getTextContent` method, in order to detect textContent which is outside of the page, hence it makes sense to ensure that it's formatted as expected.
Furthermore, by normalizing this once on the worker-tread we should no longer have to worry about a possibly negative width/height in the `PageViewport` constructor.

Finally, the patch also simplifies the `view`-getter a little bit.
---
 src/core/document.js         | 23 ++++++++++-------------
 src/display/display_utils.js |  8 ++++----
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/src/core/document.js b/src/core/document.js
index 37a1597c43e44..e733d881cdb1d 100644
--- a/src/core/document.js
+++ b/src/core/document.js
@@ -146,14 +146,14 @@ class Page {
     if (this.xfaData) {
       return this.xfaData.bbox;
     }
-
-    const box = this._getInheritableProperty(name, /* getArray = */ true);
+    let box = this._getInheritableProperty(name, /* getArray = */ true);
 
     if (Array.isArray(box) && box.length === 4) {
-      if (box[2] - box[0] !== 0 && box[3] - box[1] !== 0) {
+      box = Util.normalizeRect(box);
+      if (box[2] - box[0] > 0 && box[3] - box[1] > 0) {
         return box;
       }
-      warn(`Empty /${name} entry.`);
+      warn(`Empty, or invalid, /${name} entry.`);
     }
     return null;
   }
@@ -190,18 +190,15 @@ class Page {
     // extend beyond the boundaries of the media box. If they do, they are
     // effectively reduced to their intersection with the media box."
     const { cropBox, mediaBox } = this;
-    let view;
-    if (cropBox === mediaBox || isArrayEqual(cropBox, mediaBox)) {
-      view = mediaBox;
-    } else {
+
+    if (cropBox !== mediaBox && !isArrayEqual(cropBox, mediaBox)) {
       const box = Util.intersect(cropBox, mediaBox);
-      if (box && box[2] - box[0] !== 0 && box[3] - box[1] !== 0) {
-        view = box;
-      } else {
-        warn("Empty /CropBox and /MediaBox intersection.");
+      if (box && box[2] - box[0] > 0 && box[3] - box[1] > 0) {
+        return shadow(this, "view", box);
       }
+      warn("Empty /CropBox and /MediaBox intersection.");
     }
-    return shadow(this, "view", view || mediaBox);
+    return shadow(this, "view", mediaBox);
   }
 
   get rotate() {
diff --git a/src/display/display_utils.js b/src/display/display_utils.js
index f6d245741dd34..4b9c41164e3de 100644
--- a/src/display/display_utils.js
+++ b/src/display/display_utils.js
@@ -224,13 +224,13 @@ class PageViewport {
     if (rotateA === 0) {
       offsetCanvasX = Math.abs(centerY - viewBox[1]) * scale + offsetX;
       offsetCanvasY = Math.abs(centerX - viewBox[0]) * scale + offsetY;
-      width = Math.abs(viewBox[3] - viewBox[1]) * scale;
-      height = Math.abs(viewBox[2] - viewBox[0]) * scale;
+      width = (viewBox[3] - viewBox[1]) * scale;
+      height = (viewBox[2] - viewBox[0]) * scale;
     } else {
       offsetCanvasX = Math.abs(centerX - viewBox[0]) * scale + offsetX;
       offsetCanvasY = Math.abs(centerY - viewBox[1]) * scale + offsetY;
-      width = Math.abs(viewBox[2] - viewBox[0]) * scale;
-      height = Math.abs(viewBox[3] - viewBox[1]) * scale;
+      width = (viewBox[2] - viewBox[0]) * scale;
+      height = (viewBox[3] - viewBox[1]) * scale;
     }
     // creating transform for the following operations:
     // translate(-centerX, -centerY), rotate and flip vertically,