Adjusted keyboard nav in gif selector to reduce vertical scroll jumps

refs https://github.com/TryGhost/Team/issues/1225

- `TAB` / `SHIFT+TAB` now cycle through gifs in the search return order. It means the highlight gif will not always be in the next column over but it drastically reduces the vertical scroll jumping
- `LEFT` / `RIGHT` now select the gif to the left/right that visually lines up with the top third of the currently highlighted gif and will stop at the grid edges. The result is `UP` / `DOWN` / `LEFT` / `RIGHT` act more like spatial navigation with no unexpected scroll jumps
- switching to only storing the highlighted gif and relying on indexes added to each gif by the `tenor` service when assigning to columns means that column number changes when resizing the viewport are automatically handled

ghost/admin/app/services/tenor.js

@@ -200,6 +200,9 @@ export default class TenorService extends Service {
         // add to general gifs list
         this.gifs.push(gif);
 
+        // store index for use in templates and keyboard nav
+        gif.index = this.gifs.indexOf(gif);
+
         // add to least populated column
         this._addGifToColumns(gif);
     }
@@ -211,6 +214,10 @@ export default class TenorService extends Service {
         // use a fixed width when calculating height to compensate for different overall sizes
         this._columnHeights[columnIndex] += 300 * gif.ratio;
         this.columns[columnIndex].push(gif);
+
+        // store the column indexes on the gif for use in keyboard nav
+        gif.columnIndex = columnIndex;
+        gif.columnRowIndex = this.columns[columnIndex].length - 1;
     }
 
     _resetColumns() {

ghost/admin/lib/koenig-editor/addon/components/koenig-card-image/selector-tenor.hbs

@@ -33,7 +33,8 @@
                                     @gif={{gif}}
                                     @select={{fn this.select gif}}
                                     @isHighlighted={{eq gif this.highlightedGif}}
-                                    {{scroll-into-view (eq gif this.highlightedGif) offset=20}} />
+                                    {{scroll-into-view (eq gif this.highlightedGif) offset=20}}
+                                    data-tenor-index={{gif.index}}
                             {{/each}}
                         </div>
                     {{/each}}

ghost/admin/lib/koenig-editor/addon/components/koenig-card-image/selector-tenor.js

@@ -12,20 +12,7 @@ const THREE_COLUMN_WIDTH = 940;
 export default class KoenigCardImageTenorSelector extends Component {
     @service tenor;
 
-    @tracked highlightedColumnIndex;
+    @tracked highlightedGif;
-    @tracked highlightedRowIndex;
-
-    get highlightedGif() {
-        if (this.highlightedColumnIndex === undefined || this.highlightedRowIndex === undefined) {
-            return null;
-        }
-
-        return this.tenor.columns[this.highlightedColumnIndex][this.highlightedRowIndex];
-    }
-
-    get highlightedColumn() {
-        return this.tenor.columns[this.highlightedColumnIndex];
-    }
 
     willDestroy() {
         super.willDestroy(...arguments);
@@ -91,74 +78,117 @@ export default class KoenigCardImageTenorSelector extends Component {
 
     @action
     clearHighlight() {
-        this.highlightedColumnIndex = undefined;
+        this.highlightedGif = undefined;
-        this.highlightedRowIndex = undefined;
     }
 
     @action
     highlightFirst() {
-        this.highlightedColumnIndex = 0;
+        this.highlightedGif = this.tenor.gifs[0];
-        this.highlightedRowIndex = 0;
     }
 
     @action
     highlightNext() {
-        if (this.highlightedColumnIndex === this.tenor.columns.length - 1) {
+        if (this.highlightedGif === this.tenor.gifs[this.tenor.gifs.length - 1]) {
-            // at the end of a row, drop down to the next one
-            const newColumn = 0;
-            const newRow = this.highlightedRowIndex + 1;
-
-            if (newRow >= this.tenor.columns[newColumn].length) {
             // reached the end, do nothing
             return;
         }
 
-            this.highlightedColumnIndex = newColumn;
+        this.highlightedGif = this.tenor.gifs[this.highlightedGif.index + 1];
-            this.highlightedRowIndex = newRow;
-        } else {
-            // mid-row, move to next column
-            this.highlightedColumnIndex += 1;
-        }
     }
 
     @action
     highlightPrev() {
-        if (this.highlightedColumnIndex === 0) {
+        if (this.highlightedGif.index === 0) {
-            // at the start of a row, jump up to the prev one
-            const newColumn = this.tenor.columns.length - 1;
-            const newRow = this.highlightedRowIndex - 1;
-
-            if (newRow < 0) {
             // reached the beginning, focus the search bar
             return this.focusSearch();
         }
 
-            this.highlightedColumnIndex = newColumn;
+        this.highlightedGif = this.tenor.gifs[this.highlightedGif.index - 1];
-            this.highlightedRowIndex = newRow;
-        } else {
-            // mid-row, move to prev column
-            this.highlightedColumnIndex -= 1;
-        }
     }
 
     @action
     moveHighlightDown() {
-        if (this.highlightedRowIndex === this.highlightedColumn.length - 1) {
+        const nextGif = this.tenor.columns[this.highlightedGif.columnIndex][this.highlightedGif.columnRowIndex + 1];
-            // aready at bottom, do nothing
-            return;
-        }
 
-        this.highlightedRowIndex += 1;
+        if (nextGif) {
+            this.highlightedGif = nextGif;
+        }
     }
 
     @action
     moveHighlightUp() {
-        if (this.highlightedRowIndex === 0) {
+        const nextGif = this.tenor.columns[this.highlightedGif.columnIndex][this.highlightedGif.columnRowIndex - 1];
-            // already at top, focus to the search bar
+
+        if (nextGif) {
+            this.highlightedGif = nextGif;
+        } else {
+            // already at top, focus the search bar
+            return this.focusSearch();
+        }
+    }
+
+    @action
+    moveHighlightRight() {
+        if (this.highlightedGif.columnIndex === this.tenor.columns.length - 1) {
+            // we don't wrap and we're on the last column, do nothing
+            return;
+        }
+
+        this._moveToNextHorizontalGif('right');
+    }
+
+    @action
+    moveHighlightLeft() {
+        if (this.highlightedGif.index === 0) {
+            // on the first Gif, focus the search bar
             return this.focusSearch();
         }
 
-        this.highlightedRowIndex -= 1;
+        if (this.highlightedGif.columnIndex === 0) {
+            // we don't wrap and we're on the first column, do nothing
+            return;
+        }
+
+        this._moveToNextHorizontalGif('left');
+    }
+
+    _moveToNextHorizontalGif(direction) {
+        const highlightedElem = document.querySelector(`[data-tenor-index="${this.highlightedGif.index}"]`);
+        const highlightedElemRect = highlightedElem.getBoundingClientRect();
+
+        let x;
+        if (direction === 'left') {
+            x = highlightedElemRect.left - (highlightedElemRect.width / 2);
+        } else {
+            x = highlightedElemRect.right + (highlightedElemRect.width / 2);
+        }
+
+        let y = highlightedElemRect.top + (highlightedElemRect.height / 3);
+
+        let foundGifElem;
+        let jumps = 0;
+
+        // we might hit spacing between gifs, keep moving up 5 px until we get a match
+        while (!foundGifElem) {
+            let possibleMatch = document.elementFromPoint(x, y)?.closest('[data-tenor-index]');
+
+            if (possibleMatch?.dataset.tenorIndex !== undefined) {
+                foundGifElem = possibleMatch;
+                break;
+            }
+
+            jumps += 1;
+            y -= 5;
+
+            if (jumps > 10) {
+                // give up to avoid infinite loop
+                break;
+            }
+        }
+
+        if (foundGifElem) {
+            this.highlightedGif = this.tenor.gifs[foundGifElem.dataset.tenorIndex];
+        }
     }
 
     @onKey('Tab')
@@ -186,7 +216,7 @@ export default class KoenigCardImageTenorSelector extends Component {
     handleLeft(event) {
         if (this.highlightedGif) {
             event.preventDefault();
-            this.highlightPrev();
+            this.moveHighlightLeft();
         }
     }
 
@@ -194,7 +224,7 @@ export default class KoenigCardImageTenorSelector extends Component {
     handleRight(event) {
         if (this.highlightedGif) {
             event.preventDefault();
-            this.highlightNext();
+            this.moveHighlightRight();
         }
     }