Use line-clamp and (not fully supported) -webkit-box display for a pure-css...

Use line-clamp and (not fully supported) -webkit-box display for a pure-css multi-line caption truncation.

__tests__/src/components/GalleryView.test.js

@@ -9,7 +9,7 @@ function createWrapper(props) {
   return shallow(
     <GalleryView
       canvases={manifesto.create(manifestJson).getSequences()[0].getCanvases()}
-      classes={{ currentCanvas: 'currentCanvas' }}
+      classes={{ galleryViewItemCurrent: 'galleryViewItemCurrent' }}
       window={{
         canvasIndex: 0,
         id: '1234',
@@ -34,7 +34,7 @@ describe('GalleryView', () => {
     expect(wrapper.find('div[role="button"]').length).toBe(3);
   });
   it('sets a mirador-current-canvas class on current canvas', () => {
-    expect(wrapper.find('div[role="button"]').at(0).props().className).toEqual('currentCanvas');
+    expect(wrapper.find('div[role="button"]').at(0).props().className).toEqual('galleryViewItemCurrent');
   });
   it('renders the canvas labels for each canvas in canvas items', () => {
     expect(wrapper.find('WithStyles(Typography)').length).toBe(3);

src/components/GalleryView.js

@@ -47,7 +47,7 @@ export class GalleryView extends Component {
                     aspectRatio={manifestoCanvas.aspectRatio}
                     style={{ margin: '0 auto' }}
                   />
-                  <Typography variant="caption">
+                  <Typography variant="caption" className={classes.galleryViewCaption}>
                     {manifestoCanvas.getLabel()}
                   </Typography>
                 </div>

src/containers/GalleryView.js

@@ -30,6 +30,16 @@ const styles = theme => ({
     padding: '50px 0 50px 20px',
     width: '100%',
   },
+  galleryViewCaption: {
+    boxOrient: 'vertical',
+    display: '-webkit-box',
+    height: '3em',
+    lineClamp: '2',
+    lineHeight: '1.5em',
+    overflow: 'hidden',
+    textOverflow: 'ellipsis',
+    wordBreak: 'break-word',
+  },
   galleryViewItem: {
     '&:focus': {
       outline: 'none',