Fix: Scaling canvas context when the canvas re-scales (#347)

box · Aug 29, 2017 · 1bfa954 · 1bfa954
1 parent 2318581
commit 1bfa954
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diff --git a/src/lib/annotations/doc/__tests__/docAnnotatorUtil-test.js b/src/lib/annotations/doc/__tests__/docAnnotatorUtil-test.js
@@ -224,6 +224,11 @@ describe('lib/annotations/doc/docAnnotatorUtil', () => {
 
         beforeEach(() => {
             stubs.annotationLayer = document.createElement('canvas');
+            stubs.context = {
+                scale: sandbox.stub()
+            };
+            sandbox.stub(stubs.annotationLayer, 'getContext').returns(stubs.context);
+
             stubs.pageEl = {
                 getBoundingClientRect: sandbox.stub().returns({
                     width,
@@ -252,6 +257,7 @@ describe('lib/annotations/doc/docAnnotatorUtil', () => {
             expect(scaledCanvas.height).equals(stubs.canvasHeight * pxRatio);
             expect(scaledCanvas.style.width).equals(`${width}px`);
             expect(scaledCanvas.style.height).equals(`${stubs.canvasHeight}px`);
+            expect(stubs.annotationLayer.getContext).to.be.called;
         });
     });
 

diff --git a/src/lib/annotations/doc/docAnnotatorUtil.js b/src/lib/annotations/doc/docAnnotatorUtil.js
@@ -388,6 +388,9 @@ export function scaleCanvas(pageEl, annotationLayerEl) {
     if (pxRatio !== 1) {
         scaledCanvas.style.width = `${width}px`;
         scaledCanvas.style.height = `${height}px`;
+
+        const context = annotationLayerEl.getContext('2d');
+        context.scale(pxRatio, pxRatio);
     }
 
     return scaledCanvas;