From 88304c9b5b00d1bb7a71fa4190715356d0625736 Mon Sep 17 00:00:00 2001
From: Tony Jin <github@tonyjin.com>
Date: Tue, 11 Apr 2017 15:58:48 -0700
Subject: [PATCH] Update: Decrease mobile web max pdf.js canvas size to 3MP
 (#66)

- This should help prevent memory issues on mobile web
---
 src/lib/viewers/doc/DocBaseViewer.js                | 4 ++++
 src/lib/viewers/doc/__tests__/DocBaseViewer-test.js | 8 +++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/lib/viewers/doc/DocBaseViewer.js b/src/lib/viewers/doc/DocBaseViewer.js
index 911af7b01..a639dc72c 100644
--- a/src/lib/viewers/doc/DocBaseViewer.js
+++ b/src/lib/viewers/doc/DocBaseViewer.js
@@ -32,6 +32,7 @@ const MAX_SCALE = 10.0;
 const MIN_SCALE = 0.1;
 const DEFAULT_RANGE_REQUEST_CHUNK_SIZE = 393216; // 384KB
 const LARGE_RANGE_REQUEST_CHUNK_SIZE = 1048576; // 1MB
+const MOBILE_MAX_CANVAS_SIZE = 2949120; // ~3MP 1920x1536
 const SHOW_PAGE_NUM_INPUT_CLASS = 'show-page-number-input';
 const IS_SAFARI_CLASS = 'is-safari';
 const SCROLL_EVENT_THROTTLE_INTERVAL = 200;
@@ -661,6 +662,9 @@ class DocBaseViewer extends BaseViewer {
 
         // Disable text layer if user doesn't have download permissions
         PDFJS.disableTextLayer = !checkPermission(file, PERMISSION_DOWNLOAD);
+
+        // Decrease mobile canvas size to ~3MP (1920x1536)
+        PDFJS.maxCanvasPixels = Browser.isMobile() ? MOBILE_MAX_CANVAS_SIZE : PDFJS.maxCanvasPixels;
     }
 
     /**
diff --git a/src/lib/viewers/doc/__tests__/DocBaseViewer-test.js b/src/lib/viewers/doc/__tests__/DocBaseViewer-test.js
index 82249c735..56afee1e6 100644
--- a/src/lib/viewers/doc/__tests__/DocBaseViewer-test.js
+++ b/src/lib/viewers/doc/__tests__/DocBaseViewer-test.js
@@ -27,6 +27,7 @@ const DEFAULT_SCALE_DELTA = 1.1;
 const MAX_SCALE = 10.0;
 const MIN_SCALE = 0.1;
 const SCROLL_END_TIMEOUT = 500;
+const MOBILE_MAX_CANVAS_SIZE = 2949120; // ~3MP 1920x1536
 
 const sandbox = sinon.sandbox.create();
 let docBase;
@@ -1055,7 +1056,6 @@ describe('src/lib/viewers/doc/DocBaseViewer', () => {
 
         it('should enable range requests if the file and browser meet the conditions', () => {
             stubs.browser.returns('Chrome');
-
             docBase.setupPdfjs();
             expect(PDFJS.disableRange).to.be.false;
         });
@@ -1069,6 +1069,12 @@ describe('src/lib/viewers/doc/DocBaseViewer', () => {
             docBase.setupPdfjs();
             expect(PDFJS.disableTextLayer).to.be.true;
         });
+
+        it('should decrease max canvas size to 3MP if on mobile', () => {
+            sandbox.stub(Browser, 'isMobile').returns(true);
+            docBase.setupPdfjs();
+            expect(PDFJS.maxCanvasPixels).to.equal(MOBILE_MAX_CANVAS_SIZE);
+        });
     });
 
     describe('initAnnotations()', () => {