Tips for compelling diagrams with draw.io
Use draw.io to create compelling diagrams and get people to pay attention to your diagrams.
A friend reached out to me and asked for some tips on creating diagrams with draw.io. I checked Medium.com as well as the web to see if there are any useful articles along the lines of what I want to share and did not find any so I have written this article.
This article does not focus on the basics of draw.io. Instead, emphasis is given to the ‘what’ features in draw.io can be easily utilized for creating compelling diagrams. Given that design principles are tool agnostic, so I won’t delve into the ‘why’ of design principles but I will share URLs where relevant.
There is a fair amount of overlap between draw.io and Lucidchart, so if you are a Lucidchart user, feel free to read along. Many of these concepts can also be applied in Visio, Omnigraffle or PowerPoint although the UI names and UI elements are located in different parts of the UIs.
Readability and color
Black text color
The first thing I like to do when adding text to a diagram is change the black text from the default hex value of #000000. This color presents various readability issues, including eye strain. (More explanation here.) At least one designer recommends using the hex color #212427, but if you find that too difficult to memorize, you can use a value like #222222 and get close-enough results.
Click the color picker next to the “Font Color” label in the right-hand navigation bar to select and apply the font setting.
Depending on your display and settings it might be difficult to see the subtle differences between the black colors #000000, #212427 and #222222. Here is a sample:
Line color
Box edges and arrows/lines can also achieve better readability by avoiding the pure black color. After selecting your box shapes and lines, go to the “Text” tab in the right-hand navigation menu and click the color picker next to the “Line” label to enter and apply the hex color #222222 (or similar).
Lines and arrows
Draw.io provides all kinds of arrow options. Depending on your diagram’s purpose, audience and delivery mechanism (PDF, embedded image in a PowerPoint, printed document, etc.) you will want to consider different settings but here are the default overrides I typically apply when I need to draft up a diagram quickly.
Arrowheads
After adding a line/arrow to your diagram (and keeping the line selected), go to the “Style” tab in the right-hand navigation bar and change the arrowhead style to option #8 from the pull-down menu. Change the “Line end” Size value from 6 to 12. The readability improves dramatically:
Line curves
There are three line curve styles in Draw.io: Sharp, Rounded and Curved. The Sharp style feels rigid but it does get the point across about what flows are happening between diagram components. If in doubt, stay with the “Sharp” style. To make your diagram’s lines aesthetically pleasing, consider using the “Curved” style.
After select the line, go to the “Style” tab and select the pull-down menu next to the “Line” label to set the Curved option.
A comparison of the three different line styles:
The Sharp style is easiest to edit. The Curved style is friendlier to look at but requires more effort to edit.
Depth of curve
The depth of the “Curved” line style can be adjusted by selecting a given line (of the Curved type) and dragging the blue dot displayed near the middle area of the line. Avoid creating line curves that are dramatic. This will distract from the visual balance of the diagram.
Line overlaps
Depending on the complexity of your diagram there might be lines that overlap each other. Here too, we want the relevant level of emphasis to be expressed in the diagram.
Use of the line overlap feature looks best with either the Sharp or Rounded line types. Applying line overlap with Curved line types can be done and look okay but require additional edit effort.
If your diagram has a lot of line overlaps, consider the Rounded line type for readability. After selecting a line and setting it to the Rounded type, go to the “Line jumps” option and select the Arc setting.
Depending on the order you laid lines on the diagram, you might need to select a given line, right click and select the “To Front” option to make sure the overlap arch displays with the expected line.
In the above diagram the line arc is using the default jump size of 6. This arc size is relatively small and not noticeable by audiences that are in a hurry to understand flows between components. Consider bumping the arc size from 6 to 12:
The following diagram contrasts different line arc settings:
“Friendly rectangles”
Objects with 90 degree angles are sharp and typically not found in nature. As humans our visual response system has (likely) evolved to avoid sharp edges.
With diagrams, consider using boxes with rounded corners instead of boxes with square corners. (Additional description about rounded corners can be found here. The second part of the article delves into HTML/CSS implementation so you can skip that if you are not a web front-end designer.)
Notice the difference between the two block diagrams below.
Relative size of rounded box edges
Draw.io allows for flexible adjustments to how rounded a box edge can be but the default level of rounded edge will likely require adjustment.
After you have placed and arranged rounded boxes on your diagram, take care to make sure the rounded edges are visually balanced between larger and smaller boxes. The width and height of boxes (rounded or not) should also be checked and adjusted accordingly.
With larger rounded boxes in Draw.io, the edges become more bulky. You will need to adjust the degree of the rounded edge as the box size increases.
In the following example, the outer box in the left-hand diagram uses the default rounded edge which is bulky. The right-hand diagram shows both inner and outer box edges manually rounded to curves that are more visually balanced.
Summary of tips for Draw.io
There are definitely more tricks and tweaks to make a good diagram in Draw.io but the tips shared here will hopefully add some more pizazz to your diagrams. Summing up the points from this article:
- Change the default font and line color from pure black #000000 to something like #212427 or #222222.
- Choose an appropriate arrowhead size for arrow lines.
- Consider which line style (Straight, Curved, Rounded) you need for your diagram purpose.
- Make sure Curved style lines do not get out-of-hand with their curve depth.
- For overlapping lines, adjust the size of the line’s arc jump.
- Rounded box edges or “friendly rectangles” can also draw in the audience’s attention.
Happy diagramming!
