Pythonneries - Making Of 10

Hello,

Let’s start looking at animations in
detail. They belong to three

categories. First category is made of
entrance/exit effects who mostly are

symmetrical one of each other. I’d like
to underline that in entrance/exit effects

you find two subcategories: those that
make the object move, and those

that don’t, which are usually equivalent

to a transition. I say “usually” because,
we have seen it in the eighth video,

vidéo, “dissolve” for instance isn’t
visually exactly the same with animation

and transition. In the Commedia dell’ Arte
example, I have used “Fly-In”

to introduce each one of the characters.
It’s an entrance effect with a

movement, which can’t therefore be replaced
by a transition.

Emphasis effects change the appearance
of the object, either temporarily,

or until you advance to the next slide.
Here as well, transitions can simulate

some effects, such as a font color change or

desaturation, and cannot simulate other effects,
such as Grow/Shrink which I have also used with Arlecchino.

Motion, I’d like to say “by definition”,
cannot be replaced by

a transition, even if some transitions
that are not idempotent give a motion

feeling, but to all elements in the slide.
I have used motion too

for Arlecchino: rather than shrinking him
on the spot, jI have combined shrinking

with motion so as to place him next to
his buddies. Finally, I had a faded

transition that allowed me to replace the
image with a slightly desaturated version

of the same. The desaturation emphasis effect
wasn’t resulting in what I wanted. In passing,

a rule learned from Bruce Block’s excellent book
“The Visual Story”, desaturating colors is

an additional way, other than object size,
to reinforce a feeling

of depth and remoteness when everything
you see here

is a plane surface.

Let’s take a closer look at the various
effects, and I’ll focus in this video

on entrance effects (I’ll hardly mention
exit effects, talking about one is

talking about the other). As with transitions
they are numerous, and as with

transitions I use only a few. I mostly use
the ones that are underlined with

yellow, especially the ones underlined
with bright yellow. “Appear” probably

needs no comments; we can use two successive
slides with no transition instead,

but animation is sometimes more convenient.
I ignore for a time checkerboard,

somewhat ancillary and that I’ll talk about
later, to switch to the next bright yellow spot,

“Fly-In”. The object moves to its position following

a straight line from outside the slide,
either horizontally, vertically,

or from any corner. I believe that there
is a grammar of movement, and “Fly-in”

entrance is for me one of two cases: either
something new and remarkable,

or the irruption of the external world into
the presentation, with a cursor for instance.

There is however something to say that
isn’t particular to the “Fly-in” entrance

but that affects it in a particular way.
I apologize for bringing in childhood

memories to introduce that point. When I was a
young boy, we were solving at school what

were called problems. In these problems
there were many references to a small

city that was soon to become familiar
and that was called A.

From A a road was leading to the hardly less
famous village named B, distant from

a few miles. B looked like exerting a mysterious
attraction over the A denizens, who were leaving

early in the morning to pedal rather tranquilly
towards it. The inhabitants of B woke up with

more difficulty and were leaving later
towards A but were younger and more

energetic, or the slope was more favorable,
I don’t know, and obviously the question was

to find out when both cyclists were to
cross. Sometimes, there were variations

and you had to find out the speed, it was
never-ending fun. Anyway, what

this stamped in me was that speed
was the distance travelled by

unit of time. Far later I studied physics
and naively I kept believing that

what I had acquired in primary school
was a universal truth. My certainties,

which had held firmly so far, were blown away
when I discovered Powerpoint for which

speed is a time (as an aside, same story
in LibreOffice). If you move by one millimeter,

as long as you do it in half a second for Powerpoint

it’s very fast, even if over this distance
a snail would leave you behind. At times

I say to myself that there are places where
education sucks. On positive note, Powerpoint

concepts are sometimes closer to mine.
Alright, what is the problem with the Fly-In

entrance then? Easy to show. Let’s say that
you want to introduce Il Capitano, Pulcinella

and Arlecchino in succession. If you activate
“Fly-In” entrance for each of them using default

options, here is what you get. As you
progress, you notice a slight slowing down,

because time remains the same, and distance to
travel increasingly shorter. Obviously in

a presentation you prefer either speeding up
or keeping a constant speed. Here, you get the

feeling of a circus number that would start
with the finale before presenting average feats

and ending up by what anybody could do.
It’s a poor way to keep the audience

enthusiastic. What to do? Either come back
to classical notions of speed, and give more

time to moves that correspond to a longer
displacement. Here, it looks more

normal; or, and if you watch my videos
with attention you’ll see me using it

most often, use fly-in entrances from
either right or left

when you use them several times on the
same slide, so that travelled distances

remain very close.
Notice that if you want to put some

emphasis over the last object that flies in,
you can make it enter from a different direction.

Even if it moves slower than the other ones,
contrast will give a

kick. Fly-in entrance is something I use
only once for an object, unless a

triumphant exit from the screen justifies
a reentrance. For the next reappearances,

it will be something not as loud.
Let’s now take a look at “Peek-in”,

which proximity in the menu and similarity

of name, let me long believe that it
was a close relative of

the previous one. In fact this entrance
is far closer to the “Wipe” entrance.

Let’s take two rectangles, and let’s apply
to each of them a different entrance.

Have you seen anything, apart from a slight
blur on the left with the top rectangle and

on the right with the bottom one? In fact,
the top rectangle slides towards the right and

the bottom one is revealed. There is a motion in one
case, hence the “In”, not in the other one,

which a transition can replace. It’s far more
obvious with arrows. And with arrows,

precisely, the two animations carry a slightly
different idea. Let’s animate an arrow

from A then make B appear. With a
“peek-in” entrance, I personally feel

a very strong link of causality.
It’s “A entails B”. From A, you

cannot escape B. However, a “wipe” entrance
conveys a link that is far more

tenuous, more an idea of sequence and
time continuity, “A then B”.

Even if both entrances can be used, depending
on the idea that you want to get across,

it will be one or the other.
Sometimes, for instance to make the

image of a menu appear, both can work
- all the more as one as well as the other

is a kind of poetic vision of the
interface, as reality is

different.
However, there are cases when there

is no option. If I add a mock
hand-written annotation, both the

arrow and text want “wipe”, because that’s
how writing works.

To make a floor-lamp get out of the bag,
it’s necessary a “peek-in” entrance, here

followed by a motion. As I use in my
presentations annotations far more

often than Mary Poppins’s bag, you’ll
understand that I use “wipe” more

often than “peek-in”.
“Fade”, it’s like grey or black

in your wardrobe; you can mix it with anything,
without fearing any faux pas. We have

seen it already, between a “fade” entrance
and a “fade” transition there is no difference

except, and that’s important, when you start
animating by letter. Animating by letter,

why? I told it, a “wipe” entrance is
perfect for showing a short

annotation. As soon as the text spreads over two
lines, it falls apart. You can change options

and try to make t appear one letter at a time,
but it doesn’t work, you have a feeling that

several letters are written at once.
A faded entrance, letter by letter,

restitutes a feeling of manual handwriting.
However, with a non-script font,

for instance to simulate a data field entry,
I feel that a checkerboard entrance by letter

gives a better result. It’s the only case
when I use the checkerboard entrance.

Last useful entrances, zoom entrances. As
much as a motion, zooming is an effect

that a transition cannot apply to an
object. You can use zooming for

for a magnifying effect as I deed
(combining it with a motion)

when I introduced the Gimp toolbox;
usually in such a case I use a

faded zoom. But if zooming in
(the default option) is interesting,

zooming out, an option not available
with the faded zoom in the version

of Powerpoint I’m using, brings an
additional dimension: access from the outside,

but in a kind of transcendental way, not at
all like the object that jumps into the visual

scope with the “fly-in” entrance. It’s a bit
like annotations, the narrator getting

into the slide. It works very well with
rubber stamping too, which carries

the same idea. Everything else, unless
you are using a word that exactly matches the

name of an entrance effect, you can forget it.
I use fancy exits more often than

fancy entrances. If I take for instance
Taylor’s famous rule,

that gives the value of a continuous function
close to a point as an expression

that is a function of powers of h and successive
derivative functions in that point

(I hope it’s not Greek), I can say that
if h is small, let’s say 0.1,

the square will be 0.01, the cube 0.001 and
so forth, so I can get a rather decent

approximate value by dropping expressions
where h is raised to a higher power

and replace the function by its tangent at that
point. Saying “drop” obviously begs for

using the exit effect with the same
name. I find using “boomerang” in what

I say far more difficult.