Saturday, July 9, 2016

On displaying theorems in slides

Last week, Freddy left this comment on On why I hate LaTeX/Beamer:
We have to think something about the theorem issue. If it is a mathematical presentation, the most important contribution is indeed a theorem. Think about a math thesis presentation: most results will be theorems :(
and I replied
I agree that in a math presentations theorems have a big role. The question is how you present them. As University of Manchester Mathematics Professor Nicholas Higham in "Handbook of Writing for the Mathemetical sciences write" writes "When you write a slide, aim for economy of words. Chop sentences mercilessly to leave the bare minimum that is readily comprehensible." Think about it, people may take their theorems directly out of their latex articles and dump them into their beamer slides without further thought. That is that Beamer fosters, but ultimately it Beamer is just a tool. As I wrote on the post, the responsibility lies on the person using it. 
Let me repeat this again
 Chop sentences mercilessly to leave the bare minimum that is readily comprehensible. – N. Higham
 If we slightly modify this, we can apply this advise to good slides
Chop sentences ideas mercilessly to leave the bare minimum that is readily comprehensible but meaningful.
Meaningful in the sense that the ideas retain their meaning, that ideas are not dumbed-down. Which brings me to the concept of atomic slides.
A slide should be like an atom: the smallest unit of self-contained meaning. And just as molecules are made out atoms, so are visual stacks.

There are so many different atoms! So decay faster than others, some are heavier than other, some bond easier than other, some don't bond at all. Just like the universe mostly made of Hydrogen, most slides should resemble that character. Other important atoms for life are Carbon, Oxygen and Nitrogen.

Back to Freddy comment, here is an example out of Nicholas Higham book. No f*king Beamer!

Sunday, July 3, 2016

How to include sketches into slides

Nobody who is working alone on its own presentation should attempt this. This post is intended for people what to help a close friend, a family member or the significant other. So there you have been warn. Having said that, keep reading. I have some cool stuff to share!

For the last two weeks, I have been helping on a visual stack.  My frequent client described it as the best collaboration so far. We expanded on the "sketching theme" I wrote back in May of 2016.  Although you my client and I really like the results, I'll let the readers be the judge of it.  Here are some of the slides:

  •  Untersuchungsziele is german for Goals the of examination.  

I traced an image of a dart I found on Wikicommons. We had used the image as-is before, but this time we need to fit it into the sketch style.

  • Perspektivierung or the Perspective one takes on a topic.


Here we used show the real meaning of the word. Again, we recycled the idea, but this time I used Inkscape's Create 3D Boxes together if Inkscape's sketch Path Effect tool. I imported into Keynote as a native shape and change the type of the stoke.

  • Rahmen der Untersuchung (engl. Frame of the Examination)


Here we map the word frame to an actually frame and use the analogy of a magnifying glass for Examination.  I drew the frame with Inkscape and downloaded the magnifying glass from The Noun Project and apply the  Path Effect on the composition.

  • Institutionelle Passung 

Similar to the first example, I traced this using public domain icons from The Noun Project.

How to import sketches into slides

I'm not an artists or designer, I need to cheat to get these results. I trace images and icons on paper and scan them. On a further steps I worked the scanned images into native Keynote shapes. Here are the major steps once you have scanned the images

  • Increase the contrast of the scan image only if necessary.
  • Convert the Raster image into a vector graphics.
  • Convert the vector graphics into a native shape.

Increasing the contrast

In Gimp, duplicate the layer and set mode to Multiply

Convert Scan to SVG

In Inkscape use the Trace Bitmap Tool. I had to set the Threshold value of the Brightness cutoff to 0.8


Convert the vector graphics into a native shape

So far, so good. Here is where it starts to be painful. If you are using a Keynote, you'll need Adobe Illustration (AI) and a free plugin from Christian Holz to convert the SVG into a Keynote shape. But if you already have AI, you can convert from Bitmap to Vector inside it.

Other options

If you neither working on Keynote nor have AI, there is still hope.
  • You can do your slides in Inkscape or Scribus, or a combination and export every finished slide as png or pdf and import them into PowerPoint or Keynote, or  export the finished presentation  with all of your slides into a single pdf using Scribus.  
  • You can directly use the scanned images in your slides. If the background of the presentation matches the background of your scans you're good to go. Note that this will limit your options on how you applied your colours.

Tips on sketching

  • Use tracing paper and tape with masking tape.
  • Try different pencil types and pens.