Custom Visuals Development: Starting from Default Visuals?

[davidz106]

Hi,

I'm interested in developing custom visuals for Power BI and have a few questions regarding the starting point for such development:

1. Does Microsoft share the source code behind its default visuals (e.g., the Line chart)?
2. Is it possible to take a default visual, such as the Line chart, and programmatically add building blocks to it?
3. Or do all third-party visual developers need to start from scratch and build their visuals independently?

Use Case: We want to set up the default Microsoft Line chart with two legends. Currently, it has one legend, which could also be called "Color by" (since it distingusihes series by colors). We would like to add a second legend, which we would call "Dash by" (shape of the line). This functionality would tremendously expand the capabilities of the Line chart.

It would be extremely beneficial if developers could start from Microsoft's default visuals and simply modify or add code to create custom visuals. We would also prefer this since the speed and integration with other parts could potentially stay up there.

[dm-p]

Hi @davidz106,

No, Microsoft doesn't open-source its visuals. Even if the code were available, there are implementation differences between core visuals and custom visuals due to how MS sandboxes visuals and their APIs for third-party developers. Essentially, not all features in the core visuals are available for us unless MS creates specific APIs for us to leverage, and while they have closed some in recent years, there are still many gaps.

If you want to customize the line chart beyond the basics, you need to build all desired functionality as well. This is a common sticking point for clients approaching me for bespoke development, and it usually makes the costs untenable if all they want is a simple addition. 

This is probably not the answer you're looking for, but should hopefully confirm your questions.

Regards,

Daniel

[davidz106]

Thank you. I hope MS standpoint here changes in the future. After all, those would not modify the core visual directly but rather make a "duplicate" of it which should not interfere with core PBI functionalities.