2001.11_Vector Drawing Applications Under Linux.pdf

FEATURE

VECTOR GRAPHICS

Vector Drawing Programs

POINT, STRAIGHT ,

CURVE FRANC WIEDUWILT

The drawing of diagrams, flow charts and freely

scalable illustrations was, for a long time, the

domain of Windows software such as Corel

Draw or Micrografx Designer. In the

meantime though, a number of Linux

based programs have been created

that now compete for favour in the

creative fraternity.

The program normally used to

edit photos or to produce

pictures with photo-

realistic appearance

is Gimp. This

program is however

not suitable for the

production of accurate

drawings or diagrams that

need to be worked on in different

sizes (scalability). This is where

vector drawing programs come in

to their own. These programs are

used to construct diagrams,

assembled from simple geometrical

shapes. These shapes or objects can

also subsequently be combined,

expanded, reduced, rotated, stretched or

transformed in a variety of other ways, without

suffering any decrease in quality.

Figure 1: XFig

We present six current programs in this article, all

with one thing in common: they are all available

free of charge. You will find that the differences

otherwise outweigh the similarities.

Te st Criteria

The test candidates were put through the following

course: We first checked the installation from

Sources and Binary Packages.

In the drawing test, the programs had to show how

graphic objects were constructed, how these

objects could be transformed and filled, whether it

Pixel Graphics and Vector Graphics

The difference between how a vector drawing

program presents an element, and how a photo

(pixel) editing program presents an element, lies

in how they save their created picture data.

Vector graphics programs save their objects as

mathematical descriptions of shapes, which

require a small amount of disk and work space.

Take for example a circle, the program only has

to make a note of the middle point and the

radius. Because of this accurate mathematical

description, vector diagrams can be scaled at

will or deformed geometrically, without any loss

of quality. Photo editing programs use a pixel

based file format, in which each individual pixel,

with all its characteristics, must be stored.

Enlargements and reductions are in most cases

only possible with pixel-based pictures, with an

associated degradation in quality.

Therefore, vector drawing programs are

particularly suitable for clear structures and

technical illustrations. None of the programs

presented here have the picture effects

capability of a photo editing program like for

example Gimp.

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VECTOR GRAPHICS

FEATURE

Figure 2: Figurine’s tool bar

Figure 3: Figurine work surface

was possible to combine objects into groups and

work on them together, and whether it was simple

(or possible) to change the sequence of objects. We

also tried to find out the level of accuracy with

which one can draw in these programs.

Those of you who would like to create

illustrations or posters must also be able to work

with text. We therefore examined how (and

whether) the programs edit and transform text. In

doing this, we paid special attention to the

possibility of being able to transfer drawings to, and

read drawings from, other programs (compatibility).

Three of the presented programs support the SVG

format, which should facilitate the simple export

and import of drawings over and above the

boundaries of operating system.

We then had a look at the user support offered

by the programs in the form of on-line help and

manuals. At the end of this article, you find a table,

which lists and summarizes the most important

program functions.

not clear at first glance which functions the tool

bar icons correspond to. You can draw all the

important basic geometrical shapes and also input

and format text. Objects can be enlarged and

reduced at will and then be subsequently shape-

transformed. Xfig allows you to arrange objects on

different layers. Different line types and object fills

are possible. One thing a bit irksome about the

program, is that it is not possible to preset your

preferential ruler and drawing units.

The Xfig file format is very common in the Linux

world. Additionally, created drawings can be

exported into different pixel formats, so that

subsequent alteration work is possible in a whole

range of picture editing programs.

The program has an outstanding online helpdesk in

the HTML format. To display this however, you

must have Netscape installed. A manual in the PDF

format is in addition provided.

Xfig is particularly suitable for the production of

pictograms, flow charts, mind maps, overviews or

schematic diagrams. Xfig drawings can be

comfortably modified in texts using LaTeX.

Pixel : A point on the screen or

paper.

Binary Package : A binary

package is a combination of all

the pre-compiled files that a

program needs for its

execution. This includes other

data as well as the actual

program, for example

assistance files.

SVG : “ Scalable Vector

Graphics “, a relatively new,

non-platform-dependent

format for the storage of vector

drawing data.

HTML: “ H yper T ext M arkup

L anguage “, is a scripting

language that specifies how

web pages are formatted and

displayed on the internet.

PDF: “ P ortable D ocument

F ormat “, a file format for the

transfer of formatted text.

Sources, Source Text : The text

that the programmer enters to

write a program. The program

must be converted, with the

help of a compiler, into a

machine-readable form so that

it can be run by the operating

system.

Xfig

Xfig is considered the Methuselah of vector

drawing programs for X. The program has been

around since 1985 and is thereby substantially

older than Linux. It is included in almost all Linux

distributions.

The Xfig user interface seems somewhat

antiquated, but is however very functional. All

commands can be accessed by the large tool bar at

the left side of the program window, whereby it is

Figurine

Figurine enables you to draw diagrams in the Xfig

format with a more modern user interface.

You find the program on the Figurine homepage

in source text as well as rpm, the installation can be

carried out without any problems.

Operation is similar to Gimp: There is a small

window with drawing tools (refer to figure 2) and at

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Netscape is installed. If you do not call up the help

via the menu, you can use any browser.

Like Xfig, Figurine is particularly suitable for

creating drawings that do not have to be produced

with exact accuracy. We found it rather difficult to

draw objects of a precisely defined size.

The program supports the export of files to the

same formats as Xfig. Documents created in

Figurine can therefore be further modified in other

programs or be inserted into LaTeX documents.

Impress

Figure 4: Impress

Impress is an illustration program for folios and

other screen presentations. It is downloadable as

rpm and source text from the Impress homepage.

Like Figurine, this program has a tool bar

independent of the document window (refer to

figure 4). It however only permits one drawing to be

open at any one time.

Operating this program requires some patience,

as it is very slow – particularly with gradients and

enlargements. There are even times when one gets

the impression that the program has crashed. All

the usual basic geometrical shapes are available,

there are different line types and fill patterns as well

as many different gradient functions. Text entry is

not as simple as it could be, it must be entered into

a separate window. It is possible to enter several

lines of text at once, but this can only be formatted

in one style.

The program has neither an on-line help service

nor a manual. A special feature is the presentation

mode, in which several drawings can be displayed

one after another. Caution is recommended when

quitting out of Impress: The program does not ask

you if you want to save before quitting.

least one window with a work space for each

opened document.

Figurine offers all the important drawing tools:

Rectangles, ellipses, lines and a text tool. The text tool

does not allow the input of umlauts. These are

however correctly displayed by figurine if they are

contained in a file. Figurine offers a selection of

different line shapes and allows drawing objects to

be filled with colours and patterns. Objects can be

combined into groups and worked on together. Like

Xfig, Figurine unfortunately does not allow for the

presetting of ruler and drawing units. If you, for

example, want to have centimetres as your ruler

units, this must be reset each time. Inches are the

default unit for drawing and this cannot be changed.

Figurine has a detailed on-line help, This however

can only be displayed from within the program if

Figure 6: Sodipodi in action

Figure 5: Sodipodi’s tool bar

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Sodipodi

Sodipodi is the youngest program in this

comparison and it is taking big steps forward in its

development. On the Sodipodi homepage, you will

find the program sources and rpms. The rpms

however, are not as up to date as the source text

packages. Sodipodi uses the most current GNOME

libraries, which one must have installed (procurable

from http://www.gnome.org/ ).

The software is very similar to Gimp in both

appearance and operation. There is a very extensive

tool bar (refer to figure 5) and each drawing has its

own window. As is the case of Gimp, the tools are

accessible either by means of the tool bar or the

context menu in the document window, called up

by right mouse clicking the drawing.

It should be noted here that the program is not

fully complete yet. The basic functions for drawing

objects and for processing text however work

without problem. Objects can have different line

types, filling patterns have not yet been included.

Sodipodi is the only program in the test which can

create transparent objects (refer to figure 6), a

capability that otherwise only pixel-based programs

have. It is also possible to define your required

paper format.

There is no on-line help yet, but it is relatively

simple to get along with out it – the user interface is

very self-explanatory. All in all Sodipodi is an

interesting software development which, when it is

finished, promises to be a universal graphics

solution beside Gimp.

Figure 7: Kontour

features and innovations. You will find all Koffice

source texts and binary packages for different Linux

distributions on the KOffice homepage.

Kontour includes all the important drawing

objects. Elements can be given different line

types and fillings (patterns and gradients) and

manipulated in a whole variety of ways. Kontour

can blend two objects into each other (refer to

figure 8), and this function can produce really

cool effects. Grids and guides help to draw

objects precisely.

The software is seamlessly integrated in KOffice,

and it is therefore possible to embed drawings in

KWord and even work on them within this

program (refer to figure 9). The whole process also

rpm: “ The R ed Hat P acket

M anager “ is a program for the

installation and removal of

programs that takes into

account dependencies

between different software.

Kontour

Known earlier under the name Killustrator, Kontour

is part of the KOffice project ( http://www.koffice.

org/ ). It was renamed to get around a trademark

dispute with Adobe (see also K-splitter in this

magazine). We will limit ourselves here to the new

WMF: “ W indows M eta F ile “, a

file format for vector drawings.

Figure 8: Dissolving

Figure 9: A Kontour drawing embedded in KWord

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Figure 10: Sketch

offers different gradients for filled objects. Grids

and guides help with the construction of drawing

elements. Objects can be arranged on different

layers. The text function is at present limited to

single lined text elements, which can only be

formatted in one style. Unfortunately there is no

displayed indication of the size of the selected

object in the status bar, so that some mental

arithmetic is needed in the creation of exact-sized

objects. Sketch only allows single page drawings

at present.

Sketch was, together with Xfig and Figurine,

the most stable program in the test – it didn’t

crash once. It lacks an on-line help, but has

however a manual in HTML format. Those who

have already operated a vector drawing program

will have no problems getting acquainted with

the application.

Sketch reads and writes the Adobe Illustrator

format, so that drawings can be imported and

exported through operating system boundaries.

Furthermore, drawings can be imported from

the Xfig format and exported into different

formats (also including SVG). Sketch is suitable

not only for presentation folios or maps, but

also for accurate drawings, for example

structural drawings.

works in reverse, so that all text processing

functions available in KWord can be used in

Kontour drawings.

New to Kontour is above all the possibility of

creating multi-page documents, the capability to

drag guides out of the rulers and faster mouse

movement when working in big enlargements.

The on-line help in HTML format describes the

most important functions of the program. It is

possible to read drawings in the Xfig -, WMF -, and

SVG formats as well as write drawings in the SVG

and various bit-map formats.

The program still has some small bugs at present.

XML code is occasionally inserted into the drawing

when pasting drawing objects. Also, the gradient

path is often not saved. Nevertheless, Kontour runs

really well – you should just remember to save your

drawing frequently.

Result

As always, selection of the “correct” program for

you depends on what you want to draw: Figurine

and Xfig create charts, sketches and folios that do

not need extras such as colour gradients or special

accuracy. Impress, Sodipodi, Kontour and Sketch

are trying to advance to the class of programs

such as Corel Draw, but are however still a way

off. Sodipodi could become the perfect

supplement for Gimp, as it uses the exact same

operating concept and interface. Kontour is

particularly user friendly and its integration in the

KOffice package is another plus. Sketch has the

goal of becoming a universal drawing program for

Linux, and we are therefore awaiting its further

development with anticipation.

It is unfortunately difficult to exchange drawings

between the tested programs. Sketch, Sodipodi

and Kontour say that they support the SVG data

format. The down side is that this is a very complex

standard, which is for the most part only partly

implemented by the individual programs. As

consequence of this, these programs can not read

SVG files that were produced by other programs.

Sketch and Kontour enable the import of Xfig files

and WMF drawings, which are very common in

Windows, so that at least the import of existing

drawings is possible.

Sketch

Sketch is, similar to Kontour, a Linux based

program developed to offer a level of functionality

matching Corel Draw. With its latest version

0.6.10, Sketch seems to be well on the way to

reaching its mark. The program runs very fast,

even on older hardware. You can download

Sketch from the Sketch homepage as source or

rpm packages for different distributions. The

installation is somewhat laborious. As well as

Sketch, the following packages must also be

installed: python , python-devel , python-imaging ,

python-tk , python-tkinter , tkdev and blt . You can

find all these libraries on the Sketch homepage.

The program includes the blend function and

The author:

Franc Wieduwilt studied history and lives in Berlin

with his wife Sabine and daughter Johanna.

66 LINUX MAGAZINE 14 · 2001

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