Bug fix: preservation of viewport doesnt work

__tests__/src/actions/canvas.test.js

@@ -9,6 +9,10 @@ const mockStore = configureMockStore(middlewares);
 
 jest.mock('../../../src/state/selectors', () => ({
   getCanvasGrouping: (state, { canvasId }) => [{ id: canvasId }],
+  getConfig: jest.fn((state) => {
+    const osdConfig = { osdConfig: { preserveViewport: true } };
+    return osdConfig;
+  }),
   getNextCanvasGrouping: () => [{ id: 'canvasIndex-2' }],
   getPreviousCanvasGrouping: () => [{ id: 'canvasIndex-0' }],
 }));
@@ -24,6 +28,7 @@ describe('canvas actions', () => {
       const id = 'abc123';
       const expectedAction = {
         canvasId: 'a',
+        preserveViewport: true,
         type: ActionTypes.SET_CANVAS,
         visibleCanvases: ['a'],
         windowId: id,
@@ -42,6 +47,7 @@ describe('canvas actions', () => {
       const id = 'abc123';
       const expectedAction = {
         canvasId: 'canvasIndex-0',
+        preserveViewport: true,
         type: ActionTypes.SET_CANVAS,
         visibleCanvases: ['canvasIndex-0'],
         windowId: id,
@@ -60,6 +66,7 @@ describe('canvas actions', () => {
       const id = 'abc123';
       const expectedAction = {
         canvasId: 'canvasIndex-2',
+        preserveViewport: true,
         type: ActionTypes.SET_CANVAS,
         visibleCanvases: ['canvasIndex-2'],
         windowId: id,

src/components/OpenSeadragonViewer.js

@@ -118,7 +118,13 @@ export class OpenSeadragonViewer extends Component {
     ) {
       viewer.close();
       const canvasesChanged = !(isEqual(canvasWorld.canvasIds, prevProps.canvasWorld.canvasIds));
-      this.addAllImageSources((canvasesChanged || !viewerConfig));
+      if (canvasesChanged && viewer.preserveViewport) {
+        // Do not reset the zoom after add
+        this.addAllImageSources(false);
+      } else {
+        // Reset the zoom if the canvas has changed or if there is no viewerConfig
+        this.addAllImageSources((canvasesChanged || !viewerConfig));
+      }
     } else if (!isEqual(canvasWorld.layers, prevProps.canvasWorld.layers)) {
       this.refreshTileProperties();
     } else if (viewerConfig && !this.osdUpdating) {

src/state/actions/canvas.js

@@ -3,6 +3,7 @@ import {
   getNextCanvasGrouping,
   getPreviousCanvasGrouping,
   getCanvasGrouping,
+  getConfig,
 } from '../selectors';
 
 /**
@@ -15,6 +16,7 @@ import {
 export function setCanvas(windowId, canvasId, newGroup = undefined, options = {}) {
   return ((dispatch, getState) => {
     const state = getState();
+    const { preserveViewport } = getConfig(state).osdConfig;
     let visibleCanvases = newGroup;
 
     if (!visibleCanvases) {
@@ -25,6 +27,7 @@ export function setCanvas(windowId, canvasId, newGroup = undefined, options = {}
     dispatch({
       ...options,
       canvasId,
+      preserveViewport,
       type: ActionTypes.SET_CANVAS,
       visibleCanvases,
       windowId,