Charles Engelke’s Blog

September 23, 2012

Peter Bell’s talk on Next Generation Web Apps using Backbone.js at #StrangeLoop

Filed under: Uncategorized — Charles Engelke @ 5:47 pm

I don’t expect to have as many notes here as at my last session, because I’ll be trying to code the examples as we go. Also, the conference network is completely worthless; I’m using a Verizon MiFi, but my PC keeps dropping the connection (probably because the Apple device doesn’t like talking to a Samsung one).

We’re starting with an overview of all the well-known JavaScript MVC-ish frameworks. There are a lot of them. But at this point, I want to learn about Backbone, not frameworks in general. And we eventually get there.

We start with routers, which tell which JavaScript function should be invoked for various URLs. For example, the view for “about” would be a specific function that would be invoked when the URL ended in “#about”. We move on to views and models.

After some general overview, we start working on an example, the ToDoMVC app from Addy Osmani. At which point we start looking at tiny text in the presenter’s editor, as he tries to find his way around the example.

And, we’re at the break, and I’m leaving. This talk has been disjointed and confusing; I can browse through the example code by myself. Maybe I can sneak into the second half of another session.

Neal Ford’s Presentation Patterns talk at #StrangeLoop

Filed under: Uncategorized — Charles Engelke @ 4:00 pm

Today’s the workshops day at Strange Loop 2012, and I’m starting out with Neal Ford’s talk. I give a lot of presentations, and can always use help making them better. We’re getting a late start because the other first day activity – the Emerging Languages Workshop – ran a bit late in the morning, so the optional lunch for us workshoppers ran a bit late, too.

While we’re waiting, he showed us a PowerPoint file he uses as a “projector sanity check”, showing how it handles each color, clipping edges, different contrast ratios and a check for dead pixels. That’s going to be useful.

He focuses on some antipatterns that we should avoid.

Antipattern: Bullet-riddled corpse

Put up a bullet list, and everybody will read it right away. And then you’ll have to cover the material again and get them to pay attention to all things you’re saying that weren’t in the bullet points.

Antipattern: Floodmarks

These are like watermarks, but there are just so many of them. Trademarks, icons, and so on drowning out your presentation. This often happens when a conference requires you to use their templates. Ford says to fight this. Which he did by submitting a slide deck that complied with their template, but then ran his real deck off his own laptop.  And then won an award for the best presentation at the conference.

Floodmarks are okay on the first and last slides, but all the others should be blank canvases. And don’t put your company name on every slide, nor the the copyright notice except for the first slide. They’re just “noise”.

Infodeck versus Presentation

Infodecks and presentations look alike, but they’re totally different. An infodeck is static, while a presentation uses time through transition (moving between slides) and animation (movement within a slide). You standing in front of an infodeck isn’t adding value. An infodeck is like an essay, but presented in slides instead of paragraphs.

Pattern: Know your audience

Anticipate the questions they’ll have and put the answers into your presentation.

Pattern: Have a narrative arc

Just like telling a story: introduction and exposition, complication, climax, resolution. There may be several “subplots” each with it’s own narrative arc in your overall story.

How showed a tiny “slide sorter” view where you couldn’t see the slides, but he marked which were showing the problems and which were showing solutions, illustrating the narrative arc.

Pattern: Brain breaks

Every ten minutes or so people’s attention tends to lag, so you need a break to bring them back. Humor, violence, or sex all do that. Don’t use sex or violence in a technical talk! So put a bit of humor in every ten minutes or so.

Pattern: Unifying visual theme

Tie everything together implicitly this way.

Antipattern: Alienating artifact

Don’t try to get attention in ways that will alienate part of your audience. Sex and bigotry are good ways to do that.

Pattern: Fourthought

A pun on forethought. There are four parts: ideate (he uses mind maps), capture (in some concrete form), organize (get them into an outline, either in your presentation tool or – he uses – externally), and design (render into your presentation tool).

Pattern: Lightning talk

A short talk (usually timeboxed to five minutes or less), sometimes with a fixed format of slides. He’s going to have us do that as an exercise. Make sure it has a narrative arc, feel free to use other patterns.

Pattern: Intermezzi

A bridge between two pieces.

Antipattern: Cookie cutter

Some (most) ideas fit on more than one slide, but because slides are the “atoms” of your tool, you tend to try to fit an idea onto a single side. But more slides cost nothing, so get over over that.

Note that the “infodeck” concept wants you to use fewer slides, but for a “presentation” more slides have no downside.

Note: auto-size text is evil. Don’t let the tool encourage you to cram more things on one slide.

Antipattern: Hard transitions

One wall of text gets immediately replaced with another wall of text. The alternative?

Pattern: Soft transitions

Have a fixed element, with varying other elements that come and go. Dissolves are one way to do that. But using no transitions forces a choppy narrative, while soft transitions all you to control the flow. He also calls this a “charred trail”. Title comes up alone in the middle of the screen, then moves to the top with points coming below it, dissolving as each new one comes in. He calls this exuberant title top plus charred trail. They can print well, too.

Aside: every few minutes he brings in slides from his Halloween parties and contests. Brain breaks in practice, and an example of…

Pattern: Vacation photos

Use full-screen, high-quality images and few or no words, so long as they are relevant to your theme.

Antipattern: Slideument

That is, a slide plus a document. Try to have one deck be an infodeck and presentation slides. There are patterns that can make this less bad, but it’s still a bad idea.

Pattern: Context keeper

Example: a visual element for that context, that’s included in each slide that talks about that context. His example was “litmus tests” that he showed with actual test strips, which he moved around the corners of different parts of each slide taking about his metaphorical litmus tests.

Another example is backtracking. Have a slide introducing something, then a different slide illustrating it, then back to the first, but expanded to have more of the idea.

Antipattern: Demonstrations versus Presentations, and Live Demo versus Dead Demo

Most of the time live coding is primarily ego gratification for the presenter. Not always, of course. Tutorials and product demos use live coding well. But in a technical talk, doing all that typing is just noise.

So, tutorials good, technical deep dive bad. Product demos good, exuberant tool interaction bad. Hands-on classes good, time consuming tasks bad.

There are ways to get the benefits of live coding without doing it.

Pattern: Traveling highlights

Show code as a screen shot (with syntax highlighting) not as text. Then highlight the part you want to show, one after another. You get the kind of motion live coding gives you, without the distracting mechanics of it. Can use a colored background, or reduce the contrast of the rest of the code.

Use the screen shot even if you can get syntax highlighting and coloring in your own tool, because you don’t want the temptation to edit anything inside the presentation tool. You’ll make a mistake and not catch it.

Another option is to capture a movie of the dynamic stuff you would otherwise do live, and show that as a video in your presentation. He calls this lipsync. But don’t use this to fake anything; let the audience know it’s recorded.

Pattern: Invisibility

If you want everybody to look at you for a minute, so you can make a point, use a black slide.

Antipattern: Stale content

Leave a slide up after you start talking about something else. If you don’t want another slide for the next point, use the invisibility pattern.

There was a lot more content, too much for me to note here. And we did an exercise where we created lightning talks that was great. I really recommend his ideas. I haven’t yet read his new book, Presentation Patterns: Techniques for Crafting Better Presentations, but I feel comfortable recommending it. I got a copy as part of the talk, and will be cracking it open tonight.

September 17, 2012

AES Encryption with OpenSSL command line

Filed under: Uncategorized — Charles Engelke @ 5:03 pm

I know I’m going to forget this command line, so I’m documenting it here.

To use AES with a 128 bit key in CBC (cipher block chaining) mode to encrypt the file plaintext with key key and initialization vector iv, saving the result in the file ciphertext:

openssl aes-128-cbc -K key -iv iv -e -in plaintext -out ciphertext

To decrypt, change that -e to -d.

Warning: the values of the key and the iv must be typed in hex.

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