Irregular shaped graphical progress indicators

[Ed B]

Fundraising campaigns are often accompanied by a graphical image —traditionally a thermometer (a kind of vertical bar chart)— that is progressively filled up as donations are received.  I'm wondering how to take this to the next level in Affinity Designer with irregular shaped images instead of a thermometer —images such as vehicles, airplanes, household objects, map outlines, etc.— and filling them with a mathematically-based formula that works based on the calculated area of the image rather than just eyeballing it by appearance.  I've looked for an app to do this but no success.  (There is an area calculation service at SketchAndCalc, but it is a subscription service and is just for calculating areas, not for filling them to a specific percentage or amount.) 

[Callum]

Hi Ed B,

Its difficult to say for sure but I don't think it will be possible to do what you are looking for in Affinity specifically filling the object with a mathematically based formula. I can't imagine what you are attempting is standard practice for these sorts of images I'd expect a large majority are eyeballed or have pre defined fill levels for certain funding levels.

Thanks
C

[Ed B]

Thanks for the response, Callum.  I thought that maybe since Affinity Designer already has so much math built into it (vectors are known as math to the computer), and since the math that SketchAndCalc uses is a known thing ("The math behind SketchAndCalc is called the shoelace formula or shoelace algorithm. It also goes by the name of Gauss’s area formula and the surveyor’s formula"), that perhaps there could be a way to fill an object beginning at a given axis up to a certain percentage of the entire object.  Would it be reasonable to add that to the feature request list?   

[GarryP]

Would anyone looking at the image know, or care, that the amount of the shape that was filled was exactly the value required?

For instance, which of the shapes in my attached image is filled with exactly 50% red and 50% black?

Also, the exact fill percentage may not look ‘right’ for the shape, or the shape of the image may not allow for ‘pleasing’ results when exact measurements are used.

An automatic solution might not look ‘nice’ and therefore impel you into messing around with the result to get it looking ‘nice’.

Also, filling the shape exactly would prevent you from using certain psychological ‘tricks’, such as filling the shape ‘faster’ at the start to perhaps get more people to join in with ‘the rush’.

My advice would be to do it by eye rather than worrying about precision.

[thomaso]

21 hours ago, Ed B said:

based on the calculated area of the image rather than just eyeballing it by appearance

For what goal or advantage – if you consider that readers will have to judge your colour fills via eyeballing it by appearance ? (other than to mislead people or to use statistics to manipulate their opinions in ways like "As you can see!")

Scientifically it is well known that humans are rather bad in imagine mathematical sizes, for instance in estimating numbers (not counting) or sizes of areas of different shapes. At least since Corona we globally experienced the human limitation to imagine logarithmic increase, although this is based on a very simple formula.

Nevertheless, there is a workaround in APhoto's Histogram which displays the number of pixels of a selection:

But again, @GarryP's example illustrates & proofs the difficulties that result from your approach: not only the shape size is hard to estimate (not to mention 'judge') …

… also it can become tricky with smaller parts of a shape, as in the selection below the red parts on the right which might not get noticed by readers. Then what is the purpose of mathematical perfection?

This also leads to another problem: even if you would write below your graph that the size of the colour areas should matter, readers will intuitively rather evaluate complex shapes according to other parameters like height or width (i.e. an imaginary rectangular bounding box) – additionally encouraged to 'misread' your graph this way because they know and are used to 'understand' it that way from the huge number of rectangular bar charts.

There is various scientific literature about different visual ways that exist incidentally or used on purpose to manipulate and lead to misreading, misinterpreting, misunderstanding … and finally to "fake news". Especially for your mentioned "fundraising" goals the use of ambiguous diagrams can also achieve distrust and thus the opposite goal than the intent of conveying information and/or increasing consent.

An easy-to-create and read alternative could be for instance to display a rectangular shape and integrate the desired object illustration in one of the two areas.

[Ed B]

Hello Garry P and Thomas O.  Thank you for taking the time to provide an excellent discussion of the topic.  I hope that what you two have so generously taken the time to write will continue to be easily accessible for others who might have the same question.  Your suggestions for simplicity and a visual-factored approach confirms the conclusion that I had come to.  The current project's fundraising goal, purpose, methodology, and reporting is very simple and clear, and the progress indicator will be equally straightforward.  FWIW, what I was trying to figure out originally was a way that updating donation data as it comes in could be immediately, easily and accurately be reflected.  Cheers.

Edited September 15, 2023 by Ed B
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