Building a DXF-Compatible Rich Text Editor for a Web-Based CAD Tool

Last week I spent most of my time working on the text editor for my web-based CAD application, https://kulmanlab.com/.

This update was focused on improving DXF compatibility and making text editing more flexible, predictable, and closer to how modern design tools behave.

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📌 DXF MText Support

First of all, MText from DXF is now fully supported.

This means you can:

• Create your blueprint in any CAD tool of your choice
• Export it as DXF
• Import it into KulmanLab
• And keep text styling preserved

This was an important milestone because DXF text handling is often inconsistent between tools. Preserving formatting improves interoperability and reduces manual rework.

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🔄 Unifying Text: One Object Instead of Two

Previously, the system had two separate concepts:

• Text
• MText

I decided to simplify this.

Now everything is unified into a single Text object.

Why?

A "simple" text entity is essentially just a multiline text object with one line. Maintaining two separate implementations added complexity without much real benefit.

Unifying them makes the system:

• Easier to maintain
• More predictable
• More extensible for future formatting features

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✍️ Rich Text Editing Experience

The Text command now supports a more modern editing experience.

When placing text, you can:

• Choose font family
• Set font size
• Apply styles:
  • Bold
  • Italic
  • Strikethrough (more coming soon)

After placement, the text is rendered inside a blue bounding frame, which defines the wrapping area.

Interactive layout control

• A live resize handle allows you to adjust wrapping width dynamically
• Text reflows instantly as you resize the frame

This makes layout control much closer to what you'd expect from modern design tools rather than traditional CAD text input.

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🧠 Smart Cursor & Formatting Behavior

One of the trickier parts was making the cursor behave correctly in a mixed-format text environment.

Now:

• Cursor height adapts to the active character style
• Cursor position reflects font size changes in real time
• Mixed formatting doesn’t break alignment or insertion behavior

This ensures consistent editing even when different styles are applied within the same text block.

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📍 Multiple Attachment Points

Text objects now support multiple attachment anchors:

• Top-left
• Top-right
• Bottom-left
• Bottom-right
• Center (and others)

This makes positioning more flexible, especially in technical drawings where alignment matters.

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🎨 Character-Level Styling

One of the more powerful features is fine-grained text styling.

You can now:

• Bold individual words
• Change font size per character
• Mix fonts within a single text object
• Combine multiple styles in one sentence

This moves the editor closer to a true rich-text system rather than a simple label tool.

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📦 Frame Visibility & Layout Control

A frame toggle allows you to show or hide the bounding box around text.

This is useful for:

• Layout debugging
• Precise alignment
• Clean final rendering

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🚀 What’s Next

I believe the application is now usable enough for most basic workflows.

Next step is shifting focus toward:

• SEO optimization
• Landing page improvements
• Product promotion and visibility

The core editing engine is becoming stable enough to support this transition.

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💭 Closing Thoughts

Building a text system that behaves consistently across CAD + web constraints turned out to be more complex than expected.

But the result is a much more flexible foundation that should support future features without major rewrites.

If you're interested in web-based CAD or DXF tooling, feel free to check out:

👉 https://kulmanlab.com/