Add sprite target highlighter on sprite-tile click

src/components/stage/stage.css

@@ -89,7 +89,7 @@ to adjust for the border using a different method */
     padding-bottom: calc($stage-full-screen-stage-padding + $stage-full-screen-border-width);
 }
 
-.monitor-wrapper, .color-picker-wrapper {
+.monitor-wrapper, .color-picker-wrapper, .frame-wrapper {
     position: absolute;
     top: 0;
     left: 0;
@@ -127,3 +127,18 @@ to adjust for the border using a different method */
 .question-wrapper {
     pointer-events: auto;
 }
+
+.frame {
+    box-sizing: content-box !important;
+    background: $motion-transparent;
+    border: 2px solid $motion-primary;
+    border-radius: 0.5rem;
+    animation-name: flash;
+    animation-duration: 0.75s;
+    animation-fill-mode: forwards; /* Leave at 0 opacity after animation */
+}
+
+@keyframes flash {
+    0% { opacity: 1; }
+    100% { opacity: 0; }
+}

src/components/stage/stage.jsx

@@ -6,6 +6,7 @@ import Box from '../box/box.jsx';
 import DOMElementRenderer from '../../containers/dom-element-renderer.jsx';
 import Loupe from '../loupe/loupe.jsx';
 import MonitorList from '../../containers/monitor-list.jsx';
+import TargetHighlight from '../../containers/target-highlight.jsx';
 import Question from '../../containers/question.jsx';
 import MicIndicator from '../mic-indicator/mic-indicator.jsx';
 import {STAGE_DISPLAY_SIZES} from '../../lib/layout-constants.js';
@@ -63,6 +64,9 @@ const StageComponent = props => {
                         stageSize={stageDimensions}
                     />
                 </Box>
+                <Box className={styles.frameWrapper}>
+                    <TargetHighlight className={styles.frame} />
+                </Box>
                 {isColorPicking && colorInfo ? (
                     <Box className={styles.colorPickerWrapper}>
                         <Loupe colorInfo={colorInfo} />

src/containers/target-highlight.jsx

@@ -0,0 +1,78 @@
+import bindAll from 'lodash.bindall';
+import React from 'react';
+import PropTypes from 'prop-types';
+
+import {connect} from 'react-redux';
+import VM from 'scratch-vm';
+
+class TargetHighlight extends React.Component {
+    constructor (props) {
+        super(props);
+        bindAll(this, [
+            'getPageCoords'
+        ]);
+    }
+
+    // Transform scratch coordinates into page coordinates
+    getPageCoords (x, y) {
+        const nativeSize = this.props.vm.renderer.getNativeSize();
+        const rect = this.props.vm.renderer.canvas.getBoundingClientRect();
+        return [
+            ((rect.width / nativeSize[0]) * x) + (rect.width / 2),
+            -((rect.height / nativeSize[1]) * y) + (rect.height / 2)
+        ];
+    }
+
+    render () {
+        const {
+            className,
+            highlightedTargetId,
+            highlightedTargetTime,
+            vm
+        } = this.props;
+
+        if (!(highlightedTargetId && vm && vm.renderer)) return null;
+
+        const target = vm.runtime.getTargetById(highlightedTargetId);
+        const bounds = vm.renderer.getBounds(target.drawableID);
+        const [left, top] = this.getPageCoords(bounds.left, bounds.top);
+        const [right, bottom] = this.getPageCoords(bounds.right, bounds.bottom);
+
+        const pad = 2; // px
+
+        return (
+            <div
+                className={className}
+                // Ensure new DOM element each update to restart animation
+                key={highlightedTargetTime}
+                style={{
+                    position: 'absolute',
+                    top: `${top - pad}px`,
+                    left: `${left - pad}px`,
+                    width: `${(right - left) + (2 * pad)}px`,
+                    height: `${(bottom - top) + (2 * pad)}px`
+                }}
+            />
+        );
+    }
+}
+
+TargetHighlight.propTypes = {
+    className: PropTypes.string,
+    highlightedTargetId: PropTypes.string,
+    highlightedTargetTime: PropTypes.number,
+    vm: PropTypes.instanceOf(VM)
+};
+
+const mapStateToProps = state => ({
+    highlightedTargetTime: state.scratchGui.targets.highlightedTargetTime,
+    highlightedTargetId: state.scratchGui.targets.highlightedTargetId,
+    vm: state.scratchGui.vm
+});
+
+const mapDispatchToProps = () => ({});
+
+export default connect(
+    mapStateToProps,
+    mapDispatchToProps
+)(TargetHighlight);

src/containers/target-pane.jsx

@@ -18,6 +18,7 @@ import spriteLibraryContent from '../lib/libraries/sprites.json';
 import {handleFileUpload, spriteUpload} from '../lib/file-uploader.js';
 import sharedMessages from '../lib/shared-messages';
 import {emptySprite} from '../lib/empty-assets';
+import {highlightTarget} from '../reducers/targets';
 
 class TargetPane extends React.Component {
     constructor (props) {
@@ -109,6 +110,7 @@ class TargetPane extends React.Component {
     }
     handleSelectSprite (id) {
         this.props.vm.setEditingTarget(id);
+        this.props.onHighlightTarget(id, Date.now());
     }
     handleSurpriseSpriteClick () {
         const item = spriteLibraryContent[Math.floor(Math.random() * spriteLibraryContent.length)];
@@ -195,6 +197,7 @@ class TargetPane extends React.Component {
         const {
             onActivateTab, // eslint-disable-line no-unused-vars
             onReceivedBlocks, // eslint-disable-line no-unused-vars
+            onHighlightTarget, // eslint-disable-line no-unused-vars
             dispatchUpdateRestore, // eslint-disable-line no-unused-vars
             ...componentProps
         } = this.props;
@@ -265,6 +268,9 @@ const mapDispatchToProps = dispatch => ({
     },
     dispatchUpdateRestore: restoreState => {
         dispatch(setRestore(restoreState));
+    },
+    onHighlightTarget: (id, time) => {
+        dispatch(highlightTarget(id, time));
     }
 });
 

src/reducers/targets.js

@@ -1,8 +1,11 @@
 const UPDATE_TARGET_LIST = 'scratch-gui/targets/UPDATE_TARGET_LIST';
+const HIGHLIGHT_TARGET = 'scratch-gui/targets/HIGHLIGHT_TARGET';
 
 const initialState = {
     sprites: {},
-    stage: {}
+    stage: {},
+    highlightedTargetId: null,
+    highlightedTargetTime: null
 };
 
 const reducer = function (state, action) {
@@ -23,6 +26,11 @@ const reducer = function (state, action) {
                 .filter(target => target.isStage)[0] || {},
             editingTarget: action.editingTarget
         });
+    case HIGHLIGHT_TARGET:
+        return Object.assign({}, state, {
+            highlightedTargetId: action.targetId,
+            highlightedTargetTime: action.updateTime
+        });
     default:
         return state;
     }
@@ -37,8 +45,16 @@ const updateTargets = function (targetList, editingTarget) {
         }
     };
 };
+const highlightTarget = function (targetId, updateTime) {
+    return {
+        type: HIGHLIGHT_TARGET,
+        targetId: targetId,
+        updateTime: updateTime
+    };
+};
 export {
     reducer as default,
     initialState as targetsInitialState,
-    updateTargets
+    updateTargets,
+    highlightTarget
 };