bVisual

bVisual Blog by David Parker

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Ensuring High Contrast Text in Visio Shapes

I am working on a project where I need to ensure high contrast of the text in the Visio shapes for accessibility. At first, I attempted to write my own formula but a colleague pointed my to a website that confirms if the contrast is acceptable ( contrast-ratio.com ), and showed me that a few of my examples failed. So the search was on for a better formula than my own. This lead me to a Stack Exchange answer with just what I was looking for (Formula for Color Contrast between Text and Background). All I needed to do was to convert this into a ShapeSheet formula or two, and then I could apply it to the text inside the shapes.

VisioColorMap



Any text created with Data Graphic Text Callouts cannot have the high contrast formula applied to because they can be moved independent of the background. However any text added with Insert / Field inside the shape changes between black and white with respect to the FillForegnd value in its background.
Following the article above, it is necessary to calculate the lightness, L, of the FillForegnd, and then to check if black or white text is going to provide satisfactory contrast.

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Changing Visio Shape Size and Angle with Linked Data

I was recently laying out a computer room floor plan to scale in Visio, from survey data of the cabinets\racks within it, and it occurred to me that I could work a bit smarter than I first thought. Originally, I was going to just add lots of rectangles, size them, rotate them, and label each them with their name. Then I thought, why not use the Width, Depth and Name columns from the survey data to do most of the work for me? It was so simple to do, and only took a few minutes, so I thought I would share my methodology because it demonstrates how easy it is to work smarter with Visio….

These are the simple steps shown above, written out for your education….

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Using Advanced Installer with Viso VSTO Add-Ins

I have written many add-ins for Visio over the years, some for private clients for use in-house, some as products for public release by my clients or by me, and some just to help me with my day-to-day Visio development tasks. The ease of installation is always an issue, and I have been using a digital certificate to guarantee its authenticity in almost all of these scenarios. I have also included licensing code from a third-party for some of my own products, but have been aware that the third-party product I have been using is not ideal because it needs its own registered component on the client machine. So, when a client asked that I use Advanced Installer to create the installation setups so that their licensing system could be used, then I was (and still am) all for it because it could become a better method for myself. However, there are some issues that I am overcoming through this transition ….not least that an apparently correctly assigned digital certificate was actually not valid.

InvalidDigitalCertificate
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Prototyping Visio ShapeSheet Formulas in Excel

I am working on an application where the horizontal axis of the Visio page represents dates from left to right. In fact, the each of the fixed horizontal grids are 1 day, and I need to have shapes that understand the begin date at the left edge of the shape, and the end date at the right edge of the shape. There is, therefore, a number of elapsed days representing by the width of the shape. However, the underlying grid can either represent all days, or it can be changed to only represent weekdays by omitting the weekends. I struggled to find the best formula to calculate the elapsed days or weekdays between two dates in Visio ShapeSheet formulas, so I turned to Excel to provide an inspiration. The Visio ShapeSheet is modelled on the Excel worksheet, and formulas can be entered into the cells in much the same way. However, the available functions differ since Excel is mainly used for arithmetic and statistics, but Visio is used for graphics and data. In this article, I demonstrate how I used C# and Excel to construct and test formulas for use in a Visio shape.

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