Fix Markerjs3 Control Points Not Displayed On Loaded Annotations

Have you encountered an issue where control points aren't displayed on loaded annotations in markerjs3-3.7.1? You're not alone! This article dives deep into this problem, offering a comprehensive guide to help you identify and resolve it. We'll break down the potential causes, examine the provided code, and offer step-by-step solutions to get your annotations working smoothly. Let’s get started and figure out why those control points are hiding!

Understanding the Issue: Control Points Not Visible

When using markerjs3, a common problem arises when loaded annotations don't display their control points. This means you can see the annotation itself, but you can't interact with it to resize or move it. This can be frustrating, especially when you need to edit existing annotations. The core issue is that while the annotation data is being loaded, the markerjs3 library isn't correctly initializing the interactive elements (the control points) for these annotations.

In essence, control points are the handles that appear around a selected annotation, allowing users to manipulate it. Without them, annotations become static elements, defeating the purpose of an interactive annotation tool. The provided scenario highlights this perfectly: newly created annotations show control points as expected, but those loaded from a saved state do not. This discrepancy suggests a problem in how the state is being restored or how the annotations are being re-initialized. Let's delve into the code and explore the possible causes and solutions.

This problem often stems from how the annotation state is being handled during the loading process. It could be an issue with the data structure, the timing of the state restoration, or even a conflict in the rendering process. To effectively troubleshoot this, we'll examine the code snippets provided, focusing on the loadTestAnnotation and loadSampleAnnotation functions. These functions are crucial because they handle the restoration of annotation states, and any discrepancies within them could lead to the control points failing to render. By carefully analyzing these functions, we can pinpoint the exact cause and implement the necessary fixes.

Analyzing the Code: Potential Culprits

To effectively tackle this issue, let's dissect the provided Vue.js component code. The problem likely lies within how the annotations are loaded and restored using markerjs3. Here’s a breakdown of the key areas and potential issues:

1. Component Setup and Initialization

The code uses Vue.js composition API with ref to manage reactive variables. The testEditorContainer ref is linked to the DOM element where markerjs3 is mounted. The testEditor ref holds the MarkerArea instance. The initTestEditor function initializes markerjs3 when the component is mounted.

Potential Issue: The initialization sequence might have timing issues. If the image loading is asynchronous, markerjs3 might initialize before the image dimensions are available, leading to incorrect scaling or positioning of annotations.

2. loadTestAnnotation Function

This function fetches annotation data from an API (markerInfoApi.maMarkerInfoDetail) based on a markImageId. It then parses the JSON response and uses testEditor.value.restoreState to load the annotation.

Key Code Snippet:

const loadTestAnnotation = async () => {
  if (!testEditor.value) {
    return
  }

  try {
    console.log('🔍 Loading test annotation for markImageId: 1952539175934283778')

    const response = await markerInfoApi.maMarkerInfoDetail({
      markImageId: '1952539175934283778'
    })

    if (response && (response as any).markInfo) {
      const annotationState = JSON.parse((response as any).markInfo)
      console.log('🔍 Test annotation loaded:', annotationState)

      const currentState = testEditor.value.getState()
      const currentStateJson = JSON.stringify(currentState)
      const newStateJson = JSON.stringify(annotationState)

      if (currentStateJson !== newStateJson) {
        console.log('🔍 Restoring test annotation state')
        testEditor.value.restoreState(annotationState)
      } else {
        console.log('🔍 Test annotation state unchanged')
      }
    } else {
      console.log('❌ No annotation data found')
    }
  } catch (error) {
    console.error('❌ Failed to load test annotation:', error)
  }
}

Potential Issues:

• Asynchronous State Restoration: The restoreState function might be updating the state asynchronously, and the component might not be re-rendering correctly to display the control points.
• State Comparison: The state comparison logic (currentStateJson !== newStateJson) might be too strict. Even minor differences in the JSON structure (e.g., whitespace) could prevent the state from being restored.
• Data Structure Mismatch: There might be a discrepancy between the expected data structure of annotationState and what restoreState can handle.

3. loadSampleAnnotation Function

This function loads a sample annotation from a hardcoded JSON object. It’s structurally similar to loadTestAnnotation but uses a local JSON object instead of an API call.

Key Code Snippet:

const loadSampleAnnotation = () => {
  if (!testEditor.value) {
    return
  }

  // sample-state.json
  const sampleAnnotation = {
    "version": 3,
    "width": 1140,
    "height": 854.4066620402498,
    "defaultFilter": "url(#glow)",
    "markers": [
      {
        "fillColor": "#ff0000",
        "color": "#ffffff",
        "fontFamily": "Helvetica, Arial, sans-serif",
        "fontSize": {
          "value": 1,
          "units": "rem",
          "step": 0.1
        },
        "text": "Main board",
        "left": 161,
        "top": 54.541664123535156,
        "width": 550.6666870117188,
        "height": 320.66668701171875,
        "rotationAngle": 0,
        "visualTransformMatrix": {
          "a": 1,
          "b": 0,
          "c": 0,
          "d": 1,
          "e": 0,
          "f": 0
        },
        "containerTransformMatrix": {
          "a": 1,
          "b": 0,
          "c": 0,
          "d": 1,
          "e": 0,
          "f": 0
        },
        "typeName": "CaptionFrameMarker",
        "strokeColor": "#ff0000",
        "strokeWidth": 3,
        "strokeDasharray": "",
        "opacity": 1,
        "notes": "Unknown board with a lot of components."
      },
      {
        "arrowType": "end",
        "x1": 62.33332824707031,
        "y1": 718.5416641235352,
        "x2": 113,
        "y2": 289.2083511352539,
        "typeName": "ArrowMarker",
        "strokeColor": "#22c55e",
        "strokeWidth": 3,
        "strokeDasharray": "",
        "opacity": 1,
        "notes": "This must be a camera."
      },
      {
        "color": "#ec4899",
        "fontFamily": "Helvetica, Arial, sans-serif",
        "fontSize": {
          "value": 3,
          "units": "rem",
          "step": 0.1
        },
        "text": "Where's the battery?",
        "left": 627.6666870117188,
        "top": 763.2083511352539,
        "width": 445.3231201171875,
        "height": 57.33335876464844,
        "rotationAngle": 0,
        "visualTransformMatrix": {
          "a": 1,
          "b": 0,
          "c": 0,
          "d": 1,
          "e": 0,
          "f": 0
        },
        "containerTransformMatrix": {
          "a": 1,
          "b": 0,
          "c": 0,
          "d": 1,
          "e": 0,
          "f": 0
        },
        "typeName": "TextMarker",
        "strokeColor": "transparent",
        "strokeWidth": 0,
        "strokeDasharray": "",
        "opacity": 1,
        "notes": "The battery is missing!"
      }
    ]
  }

  console.log('🔍 Loading sample annotation with', sampleAnnotation.markers.length, 'markers')

  const currentState = testEditor.value.getState()
  const currentStateJson = JSON.stringify(currentState)
  const newStateJson = JSON.stringify(sampleAnnotation)

  if (currentStateJson !== newStateJson) {
    console.log('🔍 Restoring sample annotation state')
    testEditor.value.restoreState(sampleAnnotation)
  } else {
    console.log('🔍 Sample annotation state unchanged')
  }
}

Potential Issues:

• Same as loadTestAnnotation: The asynchronous state restoration, strict state comparison, and data structure mismatch issues apply here as well. If loadSampleAnnotation also fails to display control points, it strengthens the case for a core issue with how restoreState is used.

4. General Considerations

• markerjs3 Version: The issue is reported on markerjs3-3.7.1. It’s worth checking if there are any known bugs or updates related to state restoration in this version.
• Event Handling: The markerselect and markerdeselect event listeners are present but don’t directly relate to the control points issue. However, ensure that no other event handlers or external libraries interfere with markerjs3’s rendering.

By understanding these potential issues, we can move towards implementing targeted solutions. The next section will outline practical steps to troubleshoot and resolve the problem.

Troubleshooting Steps: A Practical Guide

Now that we've pinpointed the potential problem areas, let’s walk through a series of troubleshooting steps. These steps are designed to help you systematically identify and resolve the issue of missing control points on loaded annotations in markerjs3.

1. Verify Data Structure

The first step is to ensure that the annotation data being loaded is correctly structured and compatible with markerjs3. Inspect the annotationState object in the loadTestAnnotation function and the sampleAnnotation object in the loadSampleAnnotation function.

• Log the Data: Use console.log(annotationState) right before testEditor.value.restoreState(annotationState) in loadTestAnnotation. Similarly, log sampleAnnotation before restoring the state in loadSampleAnnotation.
• Compare with Documentation: Refer to the markerjs3 documentation for the expected structure of the state object. Pay close attention to the properties and their types.
• Check for Missing Properties: Ensure all required properties (like version, width, height, and markers) are present and correctly formatted. If there are any discrepancies, adjust the data accordingly.

2. Simplify State Comparison

The current state comparison logic (currentStateJson !== newStateJson) is very strict and can fail due to minor differences in JSON formatting (e.g., whitespace, key order). Let’s simplify this comparison to focus on the essential data.

• Compare Marker Arrays: Instead of comparing the entire JSON strings, compare only the markers arrays. This will ignore differences in metadata or formatting.
• Implement a Utility Function: Create a function to compare two marker arrays. This function should iterate through the arrays and compare the relevant properties of each marker (e.g., typeName, left, top, width, height).
• Example Implementation:

function compareMarkers(markers1: any[], markers2: any[]): boolean {
  if (markers1.length !== markers2.length) {
    return false
  }

  for (let i = 0; i < markers1.length; i++) {
    const marker1 = markers1[i]
    const marker2 = markers2[i]
    if (
      marker1.typeName !== marker2.typeName ||
      marker1.left !== marker2.left ||
      marker1.top !== marker2.top ||
      marker1.width !== marker2.width ||
      marker1.height !== marker2.height
    ) {
      return false
    }
  }
  return true
}

// Use this function in loadTestAnnotation and loadSampleAnnotation
if (!compareMarkers(currentState.markers, annotationState.markers)) {
  console.log('🔍 Restoring test annotation state')
  testEditor.value.restoreState(annotationState)
} else {
  console.log('🔍 Test annotation state unchanged')
}

3. Ensure Proper Initialization Timing

The timing of markerjs3 initialization relative to the image loading could be a factor. Ensure that markerjs3 is initialized only after the target image has loaded and its dimensions are available.

• Verify Image Dimensions: Log the image’s naturalWidth and naturalHeight in the targetImg.onload callback. Ensure these values are correct.
• Delay Initialization: If necessary, add a slight delay before initializing markerjs3 to ensure the image is fully loaded. However, this is generally not the best approach; a more robust solution is to rely on the onload event.
• Check for Race Conditions: Ensure that no other asynchronous operations are interfering with the initialization process. If necessary, use async/await to synchronize operations.

4. Try nextTick After Restore State

Vue.js's nextTick can help ensure that DOM updates are applied after the state has been restored. This can be crucial for markerjs3 to correctly render the control points.

• Import nextTick: Ensure you've imported nextTick from Vue (import { nextTick } from 'vue').
• Apply nextTick: Add await nextTick() after calling testEditor.value.restoreState in both loadTestAnnotation and loadSampleAnnotation.

Example Implementation:

if (currentStateJson !== newStateJson) {
  console.log('🔍 Restoring test annotation state')
  testEditor.value.restoreState(annotationState)
  await nextTick()
} else {
  console.log('🔍 Test annotation state unchanged')
}

5. Check for CSS Conflicts or Overrides

CSS styles can sometimes interfere with the rendering of markerjs3’s control points. Inspect the CSS to ensure no styles are inadvertently hiding or disabling the control points.

• Inspect Element: Use your browser’s developer tools to inspect the marker elements and check for any applied CSS styles that might be affecting the control points.
• Look for Overrides: Pay attention to styles that might be setting display: none, visibility: hidden, or opacity: 0 on the control points.
• Test in Isolation: Try running markerjs3 in a minimal environment without other CSS styles to see if the issue persists.

6. Review markerjs3 Documentation and Examples

The markerjs3 documentation and examples can provide valuable insights into the correct usage of the library and help identify any misconfigurations.

• Consult the Docs: Carefully review the documentation for the restoreState function and any related topics.
• Examine Examples: Look for examples that demonstrate state restoration and compare your implementation.
• Check for Updates: Check the markerjs3 GitHub repository or website for any known issues or updates related to state restoration in version 3.7.1.

7. Implement a Force Update (If Necessary)

In some cases, a force update might be necessary to ensure that markerjs3 re-renders the annotations and control points correctly. This should be considered as a last resort, as it indicates a potential issue with the library’s reactivity.

• Use a Key: Add a key attribute to the markerjs3 component and toggle its value to force a re-render.
• Example Implementation:

<div
  ref="testEditorContainer"
  class="border border-gray-300 bg-white"
  style="min-height: 400px;"
  :key="forceUpdateKey"
>
</div>

<script setup lang="ts">
import { ref, onMounted, nextTick } from 'vue'
// ... other imports

const forceUpdateKey = ref(0)

const loadTestAnnotation = async () => {
  // ... existing code
  if (currentStateJson !== newStateJson) {
    console.log('🔍 Restoring test annotation state')
    testEditor.value.restoreState(annotationState)
    await nextTick()
    forceUpdateKey.value++ // Increment the key to force a re-render
  } else {
    console.log('🔍 Test annotation state unchanged')
  }
}
</script>

By following these troubleshooting steps, you should be able to identify the root cause of the missing control points and implement the necessary fixes. Remember to test each step thoroughly and isolate the problem as much as possible.

Solutions and Fixes: Applying the Knowledge

After systematically troubleshooting, you're likely closer to identifying the root cause. This section provides specific solutions and code adjustments based on the potential issues discussed earlier.

1. Solution: Correct Data Structure Issues

If the issue stems from an incorrect data structure, the solution involves ensuring that the annotationState object matches the expected format by markerjs3. This typically means aligning your data model with markerjs3’s requirements.

• Validate the API Response: If you're fetching annotations from an API, verify that the API response structure matches the expected format. If necessary, transform the data before passing it to restoreState.
• Example Transformation: If your API returns markers in a different format, you might need to map them to markerjs3’s format:

const response = await markerInfoApi.maMarkerInfoDetail({
  markImageId: '1952539175934283778'
})

if (response && (response as any).markInfo) {
  const apiAnnotationState = JSON.parse((response as any).markInfo)
  // Transform API format to markerjs3 format
  const annotationState = {
    version: apiAnnotationState.version,
    width: apiAnnotationState.imageWidth,
    height: apiAnnotationState.imageHeight,
    markers: apiAnnotationState.markers.map((apiMarker) => ({
      typeName: apiMarker.type,
      left: apiMarker.x,
      top: apiMarker.y,
      width: apiMarker.width,
      height: apiMarker.height,
      // ... other properties
    })),
  }
  testEditor.value.restoreState(annotationState)
}

2. Solution: Implement Robust State Comparison

To avoid issues with strict JSON comparisons, use the compareMarkers function suggested earlier or a similar method to compare only the relevant marker properties.

• Refined Comparison: Implement a utility function that deeply compares the marker arrays, checking individual properties instead of relying on JSON stringification.
• Simplified Logic: Use this function in your loadTestAnnotation and loadSampleAnnotation functions to determine if a state restoration is necessary.
• Complete Implementation (from previous section):

function compareMarkers(markers1: any[], markers2: any[]): boolean {
  if (markers1.length !== markers2.length) {
    return false
  }

  for (let i = 0; i < markers1.length; i++) {
    const marker1 = markers1[i]
    const marker2 = markers2[i]
    if (
      marker1.typeName !== marker2.typeName ||
      marker1.left !== marker2.left ||
      marker1.top !== marker2.top ||
      marker1.width !== marker2.width ||
      marker1.height !== marker2.height
    ) {
      return false
    }
  }
  return true
}

// Use this function in loadTestAnnotation and loadSampleAnnotation
if (!compareMarkers(currentState.markers, annotationState.markers)) {
  console.log('🔍 Restoring test annotation state')
  testEditor.value.restoreState(annotationState)
} else {
  console.log('🔍 Test annotation state unchanged')
}

3. Solution: Address Initialization Timing

Ensure that markerjs3 is initialized only after the target image has loaded and its dimensions are available. This prevents issues with incorrect scaling and positioning.

• Confirm Image Loaded: Verify that the image onload event is firing correctly and that the image dimensions are available within the callback.
• Asynchronous Initialization: Use async/await to ensure that initialization occurs after the image is loaded:

const initTestEditor = async () => {
  if (!testEditorContainer.value) return

  const targetImg = document.createElement('img')
  targetImg.src = '/img/bg.jpg'

  await new Promise((resolve) => {
    targetImg.onload = () => {
      console.log('✅ Image loaded', targetImg.naturalWidth, targetImg.naturalHeight)
      resolve(true)
    }
    targetImg.onerror = () => {
      console.error('❌ Failed to load test image: /img/logo.png')
      resolve(false)
    }
  })

  if (testEditorContainer.value) {
    testEditor.value = new MarkerArea()
    testEditor.value.targetImage = targetImg
    testEditor.value.targetWidth = 600
    testEditorContainer.value.appendChild(testEditor.value)
    console.log('✅ Test editor initialized')
  }
}

4. Solution: Ensure DOM Updates with nextTick

Vue.js's nextTick ensures that DOM updates are applied after the state has been restored, allowing markerjs3 to correctly render the control points.

• Apply nextTick: Add await nextTick() after calling testEditor.value.restoreState in both loadTestAnnotation and loadSampleAnnotation.
• Example Implementation:

if (currentStateJson !== newStateJson) {
  console.log('🔍 Restoring test annotation state')
  testEditor.value.restoreState(annotationState)
  await nextTick()
} else {
  console.log('🔍 Test annotation state unchanged')
}

5. Solution: Resolve CSS Conflicts

CSS styles can interfere with the rendering of control points. Inspect and adjust CSS to ensure no styles inadvertently hide or disable them.

• Inspect Styles: Use browser developer tools to identify any conflicting styles on the marker elements.
• Override Styles: If necessary, override conflicting styles with more specific CSS rules or use markerjs3’s styling options to customize the appearance.
• Isolate Components: Test the markerjs3 component in isolation to rule out global CSS conflicts.

By implementing these solutions, you should be able to address the issue of missing control points on loaded annotations in markerjs3. Remember to test thoroughly after each fix to ensure the problem is resolved and no new issues are introduced.

Conclusion: Restoring Control

The issue of control points not displaying on loaded annotations in markerjs3 can be a tricky one, but by systematically troubleshooting and applying the appropriate solutions, you can get your annotation tool working smoothly. This article has provided a comprehensive guide, covering potential causes, detailed troubleshooting steps, and practical fixes.

Remember, the key is to understand the underlying problem, whether it’s a data structure mismatch, timing issue, or CSS conflict. By carefully analyzing your code, verifying data, and applying the suggested solutions, you can restore control over your annotations and ensure a seamless user experience. Happy annotating!