Table panel: Add alt and title text options to image cell type (#89930)

* Various updates

* Update form callbacks

* Use defaultValue as opposed to value on input

* Fix things up

* Docs

* Prettier

* Update docs

* Update label text

* Prettier

docs/sources/panels-visualizations/visualizations/table/index.md

@@ -209,6 +209,10 @@ If you have a field value that is an image URL or a base64 encoded image you can
 
 {{< figure src="/static/img/docs/v73/table_hover.gif" max-width="900px" caption="Table hover" >}}
 
+Use the **Alt text** option to set the alternative text of an image. The text will be available for screen readers and in cases when images can't be loaded.
+
+Use the **Title text** option to set the text that's displayed when the image is hovered over with a cursor.
+
 #### Sparkline
 
 Shows values rendered as a sparkline. You can show sparklines using the [Time series to table transformation](ref:time-series-to-table-transformation) on data with multiple time series to process it into a format the table can show.

packages/grafana-schema/src/common/common.gen.ts

@@ -771,6 +771,8 @@ export interface TableJsonViewCellOptions {
  * Json view cell options
  */
 export interface TableImageCellOptions {
+  alt?: string;
+  title?: string;
   type: TableCellDisplayMode.Image;
 }
 

packages/grafana-schema/src/common/table.cue

@@ -48,6 +48,8 @@ TableJsonViewCellOptions: {
 // Json view cell options
 TableImageCellOptions: {
 	type: TableCellDisplayMode & "image"
+	alt?: string
+	title?: string
 } @cuetsy(kind="interface")
 
 // Show data links in the cell

packages/grafana-ui/src/components/Table/ImageCell.tsx

@@ -3,41 +3,41 @@ import * as React from 'react';
 import { getCellLinks } from '../../utils';
 import { DataLinksContextMenu } from '../DataLinks/DataLinksContextMenu';
 
-import { TableCellProps } from './types';
+import { TableCellDisplayMode, TableCellProps } from './types';
+import { getCellOptions } from './utils';
 
 const DATALINKS_HEIGHT_OFFSET = 10;
 
 export const ImageCell = (props: TableCellProps) => {
   const { field, cell, tableStyles, row, cellProps } = props;
-
+  const cellOptions = getCellOptions(field);
+  const { title, alt } =
+    cellOptions.type === TableCellDisplayMode.Image ? cellOptions : { title: undefined, alt: undefined };
   const displayValue = field.display!(cell.value);
-
   const hasLinks = Boolean(getCellLinks(field, row)?.length);
 
+  // The image element
+  const img = (
+    <img
+      style={{ height: tableStyles.cellHeight - DATALINKS_HEIGHT_OFFSET, width: 'auto' }}
+      src={displayValue.text}
+      className={tableStyles.imageCell}
+      alt={alt}
+      title={title}
+    />
+  );
+
   return (
     <div {...cellProps} className={tableStyles.cellContainer}>
-      {!hasLinks && (
-        <img
-          style={{ height: tableStyles.cellHeight - DATALINKS_HEIGHT_OFFSET, width: 'auto' }}
-          src={displayValue.text}
-          className={tableStyles.imageCell}
-          alt=""
-        />
-      )}
+      {/* If there are no links we simply render the image */}
+      {!hasLinks && img}
+      {/* Otherwise render data links with image */}
       {hasLinks && (
         <DataLinksContextMenu
           style={{ height: tableStyles.cellHeight - DATALINKS_HEIGHT_OFFSET, width: 'auto' }}
           links={() => getCellLinks(field, row) || []}
         >
           {(api) => {
-            const img = (
-              <img
-                style={{ height: tableStyles.cellHeight - DATALINKS_HEIGHT_OFFSET, width: 'auto' }}
-                src={displayValue.text}
-                className={tableStyles.imageCell}
-                alt=""
-              />
-            );
             if (api.openMenu) {
               return (
                 <div

public/app/plugins/panel/table/TableCellOptionEditor.tsx

@@ -9,6 +9,7 @@ import { Field, Select, TableCellDisplayMode, useStyles2 } from '@grafana/ui';
 import { AutoCellOptionsEditor } from './cells/AutoCellOptionsEditor';
 import { BarGaugeCellOptionsEditor } from './cells/BarGaugeCellOptionsEditor';
 import { ColorBackgroundCellOptionsEditor } from './cells/ColorBackgroundCellOptionsEditor';
+import { ImageCellOptionsEditor } from './cells/ImageCellOptionsEditor';
 import { SparklineCellOptionsEditor } from './cells/SparklineCellOptionsEditor';
 
 // The props that any cell type editor are expected
@@ -73,6 +74,9 @@ export const TableCellOptionEditor = ({ value, onChange }: Props) => {
       {cellType === TableCellDisplayMode.Sparkline && (
         <SparklineCellOptionsEditor cellOptions={value} onChange={onCellOptionsChange} />
       )}
+      {cellType === TableCellDisplayMode.Image && (
+        <ImageCellOptionsEditor cellOptions={value} onChange={onCellOptionsChange} />
+      )}
     </div>
   );
 };

public/app/plugins/panel/table/cells/ImageCellOptionsEditor.tsx

@@ -0,0 +1,33 @@
+import { FormEvent } from 'react';
+
+import { TableImageCellOptions } from '@grafana/schema';
+import { Field, Input } from '@grafana/ui';
+
+import { TableCellEditorProps } from '../TableCellOptionEditor';
+
+export const ImageCellOptionsEditor = ({ cellOptions, onChange }: TableCellEditorProps<TableImageCellOptions>) => {
+  const onAltChange = (e: FormEvent<HTMLInputElement>) => {
+    cellOptions.alt = e.currentTarget.value;
+    onChange(cellOptions);
+  };
+
+  const onTitleChange = (e: FormEvent<HTMLInputElement>) => {
+    cellOptions.title = e.currentTarget.value;
+    onChange(cellOptions);
+  };
+
+  return (
+    <>
+      <Field
+        label="Alt text"
+        description="Alternative text that will be displayed if an image can't be displayed or for users who use a screen reader"
+      >
+        <Input onChange={onAltChange} defaultValue={cellOptions.alt} />
+      </Field>
+
+      <Field label="Title text" description="Text that will be displayed when the image is hovered by a cursor">
+        <Input onChange={onTitleChange} defaultValue={cellOptions.title} />
+      </Field>
+    </>
+  );
+};