original file name: Codeium Chat - 7riDve9rHqfoCxghVcHQhXR7X84eHuSt.md summary: The chat conversation involved a user seeking guidance on integrating scrolling text into a parallax background in a React application. Initially, the user shared code for scrolling text using <canvas> and parallax background elements. The assistant recommended handling the scrolling text using a <canvas> approach or CSS animation for better performance.

Subsequently, the conversation delved into conditionally rendering the scrolling text, adjusting its position using bottom, dynamically calculating the text height based on font properties, and setting the initial position of the scrolling text to start from the far right.

Note: This is purely the output of the chat conversation and does not contain any raw data, codebase snippets, etc. used to generate the output.

User at 12:11 pm, Jun 15, 2024

I was using this to scroll text across the <canvas> background.

 drawScrollingText() {
  // FIXME: This doesn't work anymore.
  console.log("textScrollX", this.textScrollX);

  context.clearRect(0, 0, context.canvas.width, context.canvas.height);
  context.font = 'italic 60px Arial'; // Customize as needed
  context.fillStyle = 'lightgreen'; // Text color
  context.fillText(this.textToScroll, this.textScrollX, 25); // Adjust Y coordinate as needed

  // Update the X position for the next frame
  this.textScrollX -= 50; // Adjust speed as needed

  // Reset text position if it's fully offscreen to the left
  if (this.textScrollX < -context.measureText(this.textToScroll).width) {
   this.textScrollX = this.props.canvasWidth;
  }
 }

I had dificulty troubleshooting the canvas background, so I implemented the parallax backgrounds like this:

     <div 
      className="parallax-background">

      {this.state.layers.map((layer, index) => (
       <ParallaxLayer
        key={index}
        layer={layer}
        offset={this.state.backgroundOffsetX}
        canvasHeight={this.props.canvasHeight}
       />
      ))}
     </div>

Now, I would like to try putting the scrolling text into the parallax background, maybe by adding a new layer to the this.state.layers

I don't know if that is a good idea, considering how React handles state changes.

Can you help me implement this?

Codeium at 12:11 pm, Jun 15, 2024

To incorporate scrolling text into the parallax background as a new layer, you have a few options. However, before you proceed, it's important to consider that React state updates may not be the best approach for animations that require frequent updates, like scrolling text. State updates can lead to re-renders and may affect performance.

Given this, you could handle the scrolling text in the following ways:

1. Canvas Approach: If you want to use a <canvas> for the text scrolling, you could add a method to draw the text within the existing drawParallaxLayer function (if you have access to it) or create a new function that is called alongside drawParallaxLayer. This way, you can manage the text scroll position without involving React state.

2. CSS Animation: You can achieve scrolling text with CSS animations, which would be more performant than using state updates. You could add a new ParallaxLayer component that renders a <div> with the scrolling text and uses CSS keyframes to animate the scrolling.

Here's a quick example of how you might add a CSS-based scrolling text layer:

// ScrollingTextLayer.tsx
import React from 'react';

interface ScrollingTextLayerProps {
  text: string;
  canvasHeight: number;
}

const ScrollingTextLayer: React.FC<ScrollingTextLayerProps> = ({ text, canvasHeight }) => {
  return (
    <div
      className="scrolling-text-container"
      style={{ position: 'absolute', bottom: 0, height: canvasHeight, overflow: 'hidden' }}>
      <div className="scrolling-text" style={{ whiteSpace: 'nowrap' }}>
        {text}
      </div>
    </div>
  );
};

export default ScrollingTextLayer;

And the corresponding CSS might look like this:

@keyframes scrollText {
  0% { transform: translateX(100%); }
  100% { transform: translateX(-100%); }
}

.scrolling-text-container {
  /* Additional styles for positioning if needed */
}

.scrolling-text {
  animation: scrollText 10s linear infinite; /* Adjust duration as needed */
  color: lightgreen; /* Text color */
  font: italic 60px Arial;
}

To use this in your TerminalGame component, you would add a new layer to your layers state that includes the scrolling text component. Make sure to adjust the key prop to avoid collisions with existing layers:

// Inside your TerminalGame component render method
<>
  {/* Other layers */}
  <ScrollingTextLayer text="Your scrolling text here" canvasHeight={this.props.canvasHeight} />
</>

Remember to import the ScrollingTextLayer component and add it to the list of layers in the state where you manage your parallax layers.

Choose the approach that best fits with your game's existing rendering strategy. If you're already using a canvas for rendering, it might be more consistent to draw the text on the canvas. If you're looking to minimize state updates and leverage CSS for performance, consider the second option.

User at 12:32 pm, Jun 15, 2024

My TerminalGame renders this, currently.

Where would I call the <ScrollingTextLayer>, which I've already created, keeping in mind that I only want it to render when I call it, not all the time?

When I call it, it will probably be in a timeout or some other way of turning it off.

Codeium at 12:32 pm, Jun 15, 2024

If you want to render the <ScrollingTextLayer> conditionally, you can manage its visibility with a piece of state that tracks whether the scrolling text should be shown or not. You'll update this state when you want to show or hide the text layer.

Here's how you can implement it:

1. Add a new state property to control the visibility of the scrolling text:

// Inside your TerminalGame class component
state = {
  ...this.state, // Keep existing state properties
  showScrollingText: false, // New state property
};

2. Toggle this state property using a method, which you can call based on certain events or timeouts:

toggleScrollingText = (show: boolean) => {
  this.setState({ showScrollingText: show });
};

3. Use the state property to conditionally render the <ScrollingTextLayer>:

// Inside your TerminalGame component's render method
render() {
  return (
    <>
      <div id={TerminalCssClasses.TerminalGame} style={{ position: 'relative', height: this.props.canvasHeight }}>
        {/* Existing layers */}
        {this.state.showScrollingText && (
          <ScrollingTextLayer text="Your scrolling text here" canvasHeight={this.props.canvasHeight} />
        )}
        {/* Other components */}
      </div>
      {/* ... */}
    </>
  );
}

4. Call toggleScrollingText with true or false when you want to show or hide the text layer. If you're using a timeout:

// To show the scrolling text after a delay
setTimeout(() => {
  this.toggleScrollingText(true);
}, 1000); // Adjust delay as needed

// To hide the scrolling text after some time
setTimeout(() => {
  this.toggleScrollingText(false);
}, 5000); // Adjust delay as needed

You can place the timeouts in lifecycle methods like componentDidMount, or in response to user actions, depending on when you want the scrolling text to appear and disappear. Remember to clear timeouts in componentWillUnmount to prevent memory leaks if the component is unmounted before the timeout fires.

User at 4:31 pm, Jun 15, 2024

I can see the new text scrolling, but it is behind the canvas.

I see this in the browser:

<div class="scrolling-text-container" z-index="2000" style="position: absolute; bottom: 0px; height: 100px; overflow: hidden;"><div class="scrolling-text" style="white-space: nowrap;">Terminal Velocity!</div></div>

Codeium at 4:31 pm, Jun 15, 2024

The z-index property in the div element is not being applied because it's not correctly formatted as a React inline style property. In React, inline styles are specified as objects with camelCased properties, so z-index should be zIndex.

Here's the corrected inline style for the scrolling-text-container:

<div
  className="scrolling-text-container"
  style={{
    position: 'absolute',
    bottom: 0,
    height: canvasHeight,
    overflow: 'hidden',
    zIndex: 2000 // Corrected property
  }}>
  {/* ... */}
</div>

Furthermore, to ensure that the scrolling text is displayed above the <canvas> element, you should ensure that the zIndex of the text layer is higher than that of the <canvas> and any other content you want it to overlay.

If you continue to face issues with the stacking order, double-check the following:

1. Make sure no parent element has a z-index lower than the z-index of the scrolling text container, as it can affect the stacking context.
2. Confirm that the parent element of the scrolling text has a position value other than static (for example, relative or absolute), as z-index only affects positioned elements.
3. Ensure that there are no global CSS styles that could be overriding the z-index you set.

In your TerminalGame component's render method, ensure that the <ScrollingTextLayer> component is rendered after the <canvas> so that it naturally stacks on top when using the same z-index context:

// Inside your TerminalGame component's render method
render() {
  return (
    <>
      <div id={TerminalCssClasses.TerminalGame} style={{ position: "relative", height: this.props.canvasHeight }}>
        <canvas
          style={{ position: "absolute", top: 0, left: 0, zIndex: 1 }}
          ref={this.canvasRef}
          width={this.props.canvasWidth}
          height={this.props.canvasHeight}>
        </canvas>
        {this.state.showScrollingText && (
          <ScrollingTextLayer text="Your scrolling text here" canvasHeight={this.props.canvasHeight} />
        )}
        {/* ... other components ... */}
      </div>
    </>
  );
}

Adjust the zIndex values as needed to ensure the correct stacking order.

User at 4:57 pm, Jun 15, 2024

Ok, it is now displaying properly.

Now I need to be able to change the text height. So, I would like the bottom to be based on the this.props.canvasHeight, in case that changes, and the actual text-height of the font.

How can I do that?

Codeium at 4:57 pm, Jun 15, 2024

To adjust the bottom property of the scrolling text container based on the canvasHeight and the text height, you can follow these steps:

1. Calculate Text Height: Since CSS doesn't provide a direct way to calculate the height of text, you can approximate it by using the font-size of the text. If you're using a fixed font-size, you can hardcode this value. Otherwise, you might need to measure the text height dynamically using a hidden DOM element.

2. Adjust bottom Property: You can then set the bottom property to be a function of the canvasHeight minus the text height.

Here's an example of how to dynamically calculate text height and set the bottom property:

First, you need to set up a reference to the text element so you can measure it:

// Add a ref to your ScrollingTextLayer component
const textRef = React.useRef<HTMLDivElement>(null);

// After the component has mounted, you can measure the height of the text
useEffect(() => {
  if (textRef.current) {
    const textHeight = textRef.current.clientHeight; // This gives you the height of the text
    // You can now use this value to set the bottom property or for other calculations
  }
}, []); // Empty dependency array ensures this runs once after the component mounts

Then, in your render method, use this ref and set the bottom property:

// Inside your ScrollingTextLayer or the component where you want to apply this
const ScrollingTextLayer: React.FC<ScrollingTextLayerProps> = ({ text, canvasHeight }) => {
  const bottomPosition = canvasHeight - textHeight; // You'll need to calculate textHeight

  return (
    <div
      className="scrolling-text-container"
      style={{
        position: 'absolute',
        bottom: bottomPosition, // Use the bottomPosition variable
        height: textHeight, // Set the height of the container to the text height
        zIndex: 2000,
        overflow: 'hidden',
      }}
      ref={textRef} // Attach the ref to the element
    >
      <div className="scrolling-text" style={{ whiteSpace: 'nowrap' }}>
        {text}
      </div>
    </div>
  );
};

If you want the bottom property to be dynamic based on text size changes, you would need to update the state or properties of the component whenever the text size changes. For performance reasons, avoid making these measurements or state updates frequently or in rapid succession.

Remember to account for any additional padding or spacing that may affect the total height of the text container.

User at 5:03 pm, Jun 15, 2024

How can I calculate the text-height based on the font and the font-size?

Or is there any way to query the text-height from the DOM?

Codeium at 5:03 pm, Jun 15, 2024

To calculate the text height based on the font and font-size, you can query the DOM by creating a temporary element with the same font styles, adding it to the document, measuring its dimensions, and then removing it. This technique allows you to get an accurate measurement of the text height.

Here's an example function that creates a temporary element to measure text height:

function getTextHeight(fontFamily: string, fontSize: string, text: string): number {
  // Create a temporary span element
  const span = document.createElement('span');
  span.style.fontFamily = fontFamily;
  span.style.fontSize = fontSize;
  span.style.position = 'absolute'; // Position it out of the normal document flow
  span.style.whiteSpace = 'nowrap'; // Prevent line breaks
  span.style.visibility = 'hidden'; // Make it invisible
  span.textContent = text;

  // Append the span to the body and calculate the height
  document.body.appendChild(span);
  const textHeight = span.getBoundingClientRect().height;

  // Clean up and remove the temporary span
  document.body.removeChild(span);

  return textHeight;
}

You can use this function in your React component to set the bottom property dynamically. Here's an example of how to integrate it with your ScrollingTextLayer component:

const ScrollingTextLayer: React.FC<ScrollingTextLayerProps> = ({ text, canvasHeight }) => {
  // Define the font properties
  const fontFamily = 'Arial';
  const fontSize = '60px'; // Ensure this matches your actual font size

  // Calculate the text height
  const textHeight = getTextHeight(fontFamily, fontSize, text);

  // Calculate the bottom position
  const bottomPosition = canvasHeight - textHeight;

  return (
    <div
      className="scrolling-text-container"
      style={{
        position: 'absolute',
        bottom: bottomPosition,
        height: textHeight,
        zIndex: 2000,
        overflow: 'hidden',
      }}
    >
      <div className="scrolling-text" style={{ whiteSpace: 'nowrap', fontFamily, fontSize }}>
        {text}
      </div>
    </div>
  );
};

Please note that this approach forces a reflow and repaint which can be costly in terms of performance, especially if you're doing it frequently or in a tight loop. If the text, font, and font size do not change often, you may perform this measurement once and store the value, or if they are static, you can calculate it once on component mount.

User at 5:10 pm, Jun 15, 2024

Ok, this is looking very good now.

I am still having one problem. The scrolling text starts at about the middle of the screen, but I want it to start on the far right.

I'm not sure which setting to change, or which code to change.

Codeium at 5:10 pm, Jun 15, 2024

The starting position of the scrolling text is controlled by its initial horizontal position. If the text starts in the middle of the screen, it's likely because the initial left or transform: translateX property value is not correctly set.

To ensure the scrolling text starts from the far right, you should set the initial position to the full width of the container that the scrolling text is within. If this container is the same width as the canvas or the viewport, you can use those measurements.

Here's how you might adjust the ScrollingTextLayer component:

1. Set the initial left or transform: translateX style to 100% of the parent's width, which should place the starting edge of the text just outside the right edge of the container.

// Inside your ScrollingTextLayer component
const ScrollingTextLayer: React.FC<ScrollingTextLayerProps> = ({ text, canvasHeight }) => {
  // ... other code ...

  return (
    <div
      className="scrolling-text-container"
      style={{
        position: 'absolute',
        bottom: bottomPosition, // Calculated from previous steps
        width: '100%', // Ensure this is 100% to use the full width of the parent container
        height: textHeight,
        overflow: 'hidden',
        zIndex: 2000,
      }}
    >
      <div 
        className="scrolling-text" 
        style={{
          whiteSpace: 'nowrap',
          position: 'absolute',
          left: '100%', // Start outside the container on the right
        }}
      >
        {text}
      </div>
    </div>
  );
};

2. If you're using CSS animations to move the text, ensure that the keyframes are set to translate the text from 100% to -100%.

@keyframes scrollLeft {
  from {
    transform: translateX(100%);
  }
  to {
    transform: translateX(-100%);
  }
}

.scrolling-text {
  animation: scrollLeft 10s linear infinite; // Adjust duration as needed
}

By setting the initial left property or transform: translateX to 100%, the text will start just offscreen to the right and move towards the left. If the text still doesn't start from the desired position, ensure that the parent container's width is set correctly and that there's no conflicting CSS that might affect the starting position.