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  <front>
    <journal-meta />
    <article-meta>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Jo~ao M. Cunha</string-name>
          <email>jmacunha@dei.uc.pt</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Tiago Martins</string-name>
          <email>tiagofm@dei.uc.pt</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Pedro Martins</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jo~ao Bicker</string-name>
          <email>bicker@dei.uc.pt</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Penousal Machado</string-name>
          <email>machado@dei.uc.pt</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>CISUC, Department of Informatics Engineering, University of Coimbra</institution>
        </aff>
      </contrib-group>
      <abstract>
        <p>The number of people who design typefaces has drastically increased in the last twenty years. However, not all typefaces work as they should, i.e., as a group of characters with shared attributes. We present a tool for helping type designers in their creative process, which explores the anatomic relations among characters of a typeface. Having computer-aided design as a goal, our tool helps in the early stages of designing a typeface by using semi-automatic letter-part sharing and allowing the users to compare their design with existing typefaces.</p>
      </abstract>
      <kwd-group>
        <kwd>Computational Design</kwd>
        <kwd>Computer-Aided Design</kwd>
        <kwd>Type Design</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>
        In the last century there was a massive proliferation of typefaces, being di cult
to know how many there are today [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. The accessible type design tools and the
ease of designing and releasing a typeface led to a huge number of typefaces,
whose quality is quite diverse.
      </p>
      <p>
        A typeface has a key role in terms of communication as can even change the
intent of its message. However, its importance is often overlooked and the impact
of the communication is negatively a ected by choosing an unsuitable or even
poorly designed typeface. As changing users' habits is something not feasible,
we believe that we should instead focus on trying to improve the way users
design typefaces. By doing this, we aim at increasing the overall likelihood of
the production of better quality designs by both experienced type designers and
users without a design background. One of the criteria to evaluate a typeface's
quality is its consistency { the way typeforms match each other, i.e. how the
characters are designed into a set of diversi ed and yet uni ed forms [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ].
      </p>
      <p>
        Having computer-aided design as a goal, we focus on helping the designer
in the early stages of the design process by combining type design principles,
derived during the research stage, with an exploration of the Creativity-Support
Tools domain, using mixed-initiative approaches [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ].
      </p>
      <p>We present a prototype of a type design aiding-tool which is currently
composed of two di erent components: the Part-sharing { based on the consistency
criterion { and the Adviser { which uses Self-Organizing Maps to suggest similar
designs to the user.</p>
      <p>Copyright © 2016 for this paper by its authors. Copying permitted for private and academic purposes.</p>
    </sec>
    <sec id="sec-2">
      <title>Related work</title>
      <p>The development of type related digital applications is nothing new and the
current approaches can be divided into di erent categories according to their
authors/users or their end purposes. There are three main types of authors:
designers, engineers and artists. This di erence on background knowledge has
a huge e ect on the type of application: some are purely artistic; others are
technical and often dependent on too rigid rules or structure, thus resulting
sometimes in visually non-appealing outputs; and others are within the scope
of software speci cally developed for type design { none of which explores the
domain of computational creativity to its advantage in a signi cant way. Being
more interested in type design, we will avoid addressing applications which have
a visual artifact as output and focus on those that have a font as nal product.</p>
      <p>
        CarveLCD [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] generates letters using a grid which de nes the location of
their outline-points. This grid is controlled by the user and its modi cation is
applied to every character, maintaining some coherence among them. It often
results in abstract shapes which are not easily read.
      </p>
      <p>
        Other applications allow the user to change the value of pre-de ned
parameters which control a given characteristic in order to generate fonts (e.g. Meta op
[
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], Modular typographic generator [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ], Typeconstructor [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ] and Prototypo [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ]).
      </p>
      <p>
        Schmitz [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ] developed a tool which uses Genetic Recombination as a metaphor
and allows the user to recombine a limited number of fonts generating hybrids.
This generation is done by using their genes which store information about three
features: font skeleton, line width and serif shape.
      </p>
      <p>
        There are also some systems that use Evolutionary Computation for
designing type. Some require user interaction (e.g. [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]) and others focus on being
autonomous (e.g. Evotype [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ] which generates glyph designs from scratch).
      </p>
      <p>In spite of the existence of such applications and systems, not only none of
them addresses all the issues we have previously identi ed but also their output
is considered the nal product { we act on the initial stage of the design process.
Concerning the followed approach, most of the aforementioned applications rely
on prede ned typefaces or skeletons, whereas we aim to allow the user to input
its own designs. Additionally, the majority of them presents as nal output
something that { as a text font { has low quality both in terms of legibility and
coherence among characters.
3</p>
    </sec>
    <sec id="sec-3">
      <title>Aiding type design: Part-sharing</title>
      <p>Our tool aims at helping type designers by combining co-creativity with type
design principles. The developed prototype is currently composed of two di erent
components: the Part-sharing and the Adviser. The Part-sharing component is
strongly based on type design principles and uses them to both help designer
reduce time-consuming tasks and stimulate creativity.</p>
      <p>1. Looking for consistency { By focusing on the principle of consistency,
the rst stage of the development of the Part-sharing component has three main
goals: identify the characteristics that make a typeface work as a whole;
understand the reason for the existence of relationships among letters; and identify
the possible patterns in their construction.</p>
      <p>Our research approach consisted not only in bibliographic research but also
in the conduction of interviews with type designers. These interviews allowed us
to understand their way of working and the details they pay attention to when
drawing a typeface. In addition, we also analyzed the di erent letters, in order
to identify patterns in their construction and infer possible rules followed in the
design of a text typeface. The collected material and reached conclusions were
then used as a support and applied in the development of the application.</p>
      <p>As observed in some of the projects presented in Section 2, it is possible
to make a metaphor between typefaces and biology: di erent typefaces can be
seen as di erent species as they have a di erent structure. On the other hand,
as living creatures within the same species share a given karyotype, within a
typeface the di erent letters also share a set of characteristics.</p>
      <p>
        According to Meseguer [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], there are three distinct ways a designer can use
to create a set of characters: (1) step by step { in which each character is divided
in parts according to the calligraphic drawing and stays that way until the last
stage of the drawing process; (2) modular { which is based on the repetition of
shapes throughout the set of the characters (e.g. the stem of i is repeated on the
n or m); (3) shape derivation { characters are drawn in a sequence and shapes
are derived from others.
      </p>
      <p>Both the repetition of modules and shape derivation have key roles in terms
of giving coherence and maintaining the harmony among characters.</p>
      <p>By drawing the rst letters, it is already possible to foresee how the others
will be as making a decision for one letter often a ects the rest of the letters. The
designer is then faced with the question of which elements of the drawn letters
can be used in the new ones and which ones must be adjusted or modi ed.</p>
      <p>
        In addition, it is possible to separate the characters into several groups based
on their morphological similarity (e.g. in upper case the round shapes group is
O, Q C, G and S ; in lower case is o, c and e). This categorization is of great
importance since similar structures can and should be designed as related forms
[
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Moreover, by rstly drawing one character of each group, it is possible to
design the remaining characters with less e ort and sparing time.
      </p>
      <p>The process of designing in sequence was mentioned by all the interviewed
designers when describing their way of working. They not only share the
preference of drawing the lowercase rst { upper case is much more limited in terms of
creativity and di erentiation { but they also have a set of favorite rst letters.</p>
      <p>Most designers start with the key letters which de ne the proportions and
personality of the type, good starting points are the lowercase letters a,e,g,n
and o. The letter n is normally one of the rst, due to the fact that it is easy to
obtain parts of the letters h, m, u and r from it. And with it, it is possible to
de ne a lot of the rhythm and proportion of the typeface.</p>
      <p>2. Our approach { Our initial ideia was to establish rules that would,
in some way, allow to generate all the characters of a typeface based only on
some given by the user. The user would input some previously drawn vectorial
glyphs and then identify their parts. After identifying the letter-parts, it would
be possible to generate the rest of the letters. This generation would be based
on the prede ned rules and would use the details about the introduced glyph,
given by the user. After the generation, the user would be able to change the
generated shapes, in order to correct any imperfection, and afterwards export
the results. The goal of this concept was to generate a font nearly ready to be
used. The end version of the application works similar to what has already been
described but its main goal is completely di erent.</p>
      <p>
        As explained in Section 3 (Looking for consistency ), a system with too rigid
rules, would lead to something greatly repetitive and would probably result in
something with a modular appearance. Such a product would go against one
of our main goals: to have something serious in terms of typographic quality
and useful as a text typeface. According to Goudy [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], the characters should be
coherent among each other but at the same time each of them should have a
quality of completeness and not seem to be made of pieces put together.
Obviously, a modular-looking result would fall short of this idea. In addition, there
is often the need of doing optic compensations before considering a typeface as
nal. These were not considered in the initial concept.
      </p>
      <p>Another important issue is related to the introduced characters. As
mentioned in Section 3 (Looking for consistency ), there are some letters that allow
to foresee how the rest of the font might look like (e.g. the n or o) { by partially
de ning the proportions, contrast, etc.. However, there are others that do not
and are much more di cult to extract useful information from (e.g. k, x or z ),
consequently increasing the di culty of generating the rest of the characters.
Moreover, just a few letters are not enough to generate the all of the remaining
characters, which denotes a clear problem in our initial concept.</p>
      <p>For already mentioned reasons, the goal of the application was changed:
instead of being considered as an application able to generate a complete and
ready to use font, it should be seen as an aid-tool to the type designer, giving
support to the design task and stimulating creativity. It helps to reduce the time
spent by the designers in the initial stage of the design process.</p>
      <p>The way of working is highly similar to what has already been described. The
user is able, at any time, to add new previously drawn glyphs and identify their
parts. The shape-repetition is done automatically by the application. When the
user is satis ed with the characters drawn using the tool, he can continue the
design process with another software specially developed for type design, using
the output of our application as a draft and an initial version of the typeface.</p>
      <p>The current version is a prototype, not having all its functionalities fully
implemented. In the part-sharing component, we have chosen to begin with the
lowercase because it has a greater importance and usage { as already mentioned.
Not only that but also all the interviewed type designers start the majority of
their typefaces with the lowercase letters. The implemented rule system was
based on the identi ed shape-sharing relationships among letters (see Fig. 1).</p>
      <p>3. User input { The current version of the application was implemented
using Processing and the library Geomerative. This library was used to read
the introduced svg les and access the points and Bezier curves of the vectorial
shapes. By introducing a vectorial le, the user is rst asked to identify the
letter it corresponds to. The user is then able to identify the several parts of the
introduced glyphs. These parts are prede ned in the application, i.e. the user
has a list of possible parts to identify (based on the relationships, see left side
of Fig. 1). This identi cation is done through point selection of all the points
belonging to the part being identi ed. For example: having introduced a serifed
glyph, the user can select all the outline points which are part of the serif and
choose \serif" to save it as such. After identifying a letter-part, the application
automatically checks which letters might use it in their construction and assigns
it to them (see Fig. 2). The input is not limited: the user is able to input vectorial
les for as many letters as he/she wishes and even replace a previously given
one. This allows the user to work step-by-step in an incremental way.</p>
      <p>4. Letter-part attribution and positioning { The attribution of the
letter parts is done according to two criteria: need { does the letter need that
part or does it already have one specially drawn for it? { and suitability degree
{ is there any other already de ned letter-part which is more suitable or should
it be replaced? For example, the top part of the l stem can be used to make an
i stem but the top part of the j might be more adequate.</p>
      <p>One of the issues that had to be solved was related to the positioning of
letter-parts { i.e. how should a copied shape be positioned? The solution was to
use a letter skeleton with the several letter-parts identi ed (see right side of Fig.
1). Contrary to some of the applications mentioned in Section 2, the skeleton is
only used for letter-part positioning purposes. This is not an optimal solution as
it does not account for every style/proportion. Despite this, we do not consider
it a problem, as the user is able to move the letter-parts.</p>
      <p>The positioning according to the skeleton is also not trivial, as the positioning
method is not the same in all letter components. An example of this can be seen
in the letters n and l. The left stem of the letter n can be positioned by aligning
it to the left with the corresponding skeleton part. Di erently, the stem of the
l is centered in relation to its skeleton. This makes it necessary to previously
de ne the positioning method for each letter-part.
5. Editing shapes { In spite of not having a nal typeface as a goal output
nor aiming at developing an application to compete with software specialized in
type design, we decided that the user should be able to edit the letter shapes.
The importance of this functionality is even more evident when considering
positioning. Therefore, the user is able to both move shapes, by selecting all their
points, move single points or even their respective control points. This makes
it possible to change the generated shapes in order to correct any imperfection
and make slight adjustments (e.g. optical compensations).
4</p>
    </sec>
    <sec id="sec-4">
      <title>Aiding type design: Adviser</title>
      <p>The second component is used as a guide and its purpose is to present the user
with possible letter designs, based on a user given glyph. The suggested designs
are from already released typefaces that are similar in style to the one introduced
by the user. This functionality is particularly helpful for non-experienced users
and has two main possible uses: (i) it allows the user to see how the characters
of similar-looking typefaces were designed, thus being useful to guide the user
when designing a typeface of a speci c style; on the other hand, (ii) it helps
the user in distancing the typeface being designed from others, thus avoiding an
excess of similarity of the output.</p>
      <p>
        To implement the Adviser, we use a Self-Organizing Map (SOM) [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ], which is
a technique normally employed in data visualization, as it reveals relationships
between vast amounts of data. It consists of self-organizing neural networks
which require no external supervision and are able to represent multidimensional
data in a space of a lower number of dimensions. The output is a map which
groups similar data items together, displaying similarities.
      </p>
      <p>
        A SOM is used to produce a map of di erent character styles for each letter,
organized in terms of similarity. This makes it possible to group similar
typefaces and nd the ones visually near to a given one. Moreover, it also allows a
gradual distancing from a particular style { without getting too far from what
is established by tradition for that speci c style of typeface. It is important to
bear in mind that breaking with tradition when designing a typeface is often
not a good choice as it might have a negative e ect on legibility and easiness of
reading [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. By using SOMs, a user can start by drawing one letter and then see
di erent possibilities for other characters, ordered according to similarity degree.
      </p>
      <p>
        1. Producing SOMs { Di erently from the component described in Section
3, in the current version of the Adviser component we only used uppercase letters.
This was mainly due to fact that, the upper case is much more limited in terms of
di erentiation and creative freedom when compared to the lowercase [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. Given
that the Adviser deals with variation of style, we considered that the uppercase
was a better choice for a rst assessment of the validity of using SOMs, avoiding
the greater amount of character style variation of the lowercase.
      </p>
      <p>We produced a SOM for each letter with a dataset of 4034 typefaces. The
currently used SOMs followed the following experimental parameters: number of
iterations : 800; lattice size: 25 25; samples per character : 250.</p>
      <p>Following the production of the SOMs, we calculated the correspondence
between the dataset typefaces and the best match SOMs node for each character,
i.e. each SOM (e.g. SOM of the character A, see left side of Fig. 3) has a list of
best match node for each typeface (e.g. the node that is most similar-looking to
the glyph A of a given typeface). This establishes proximity relationships among
the typefaces from the dataset.</p>
      <p>2. Finding look-alikes { The Adviser component uses the produced SOMs
to suggest the most similar-looking typefaces, based on the glyph given by the
user. This process consists in nding the node of the character's SOM that has
the highest degree of similarity and then provide the user with a list of typefaces.
The similarity comparison is done using the Euclidean distance { also used in
the SOMs production { which compares the input glyph with each node. The
list of best matched typefaces is then produced by gathering the typefaces which
were attributed to the best matched node and the nodes that are close to it. This
results in a list ordered by similarity degree.</p>
      <p>3. Guiding the user { The interface is the same as the one developed
for the rst component, as they are part of the same tool. When using the
functionalities of the Adviser component, the user is able to click on every letter
button, even though some of the letters do not have a de ned glyph yet. This
is due to the components way of working: it does not need a glyph to show a
suggestion of a possible design.</p>
      <p>The suggestion is shown with a shadow-like e ect, being only a visual clue to
the user (see right side of Fig. 3). There are two di erent modes of suggestion:
single suggestion { only a glyph typeface is shown { and multiple suggestion
{ several are shown by overlaying them. Despite being totally functional, the
interface still needs some improvements in order to make both components t
well together in terms of usability and way of working.</p>
    </sec>
    <sec id="sec-5">
      <title>Conclusion &amp; future work</title>
      <p>We have presented and described the functionalities of a type design
aidingtool which has as main purpose to make the design process easier by reducing
time-consuming tasks and stimulating creativity. It follows a mixed-initiative
approach and is currently composed of two di erent components: the Part-sharing
{ strongly based on type design principles { and the Adviser { which uses
SelfOrganizing Maps to suggest similar designs to the user. The main goal is not
to create completely nished and ready to use typeface but instead to allow the
user to design a rst draft by using the tool as a support. It is to be used in the
early stage of the design process as the user will be able to export the typeface
draft and continue the process in an application specially developed for type
design, thus allowing the user to afterwards improve details and correct drawing
problems such as those related to optical compensations.</p>
      <p>Concerning the Advisor component, there are also issues to be solved. We
consider that the use of SOMs full ls its purpose as it allows similar typefaces to
be found. Notwithstanding, the used dataset has some clear problems which need
to be corrected: (1) Some of the typefaces used are too similar; (2) It contains
di erent weights { this is pointless, as we are only designing the regular weight.</p>
      <p>In addition, as every SOM is di erent and nds di erent similarities among
the data, more attention should be given to both SOM production and SOM
quality assessment as well as to the used experimental setup.</p>
      <p>Regarding the process of nding similar typefaces using SOMs, we aim to
further develop its way of working by focusing on multiple matching. The current
version only nds similar typefaces based on a single glyph; with multiple
matching it would be based on several glyphs, consequently aiming to nd typefaces
that match the maximum number of glyphs.</p>
    </sec>
  </body>
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