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Index des mots-clés

AGENDA PERSONNEL
ALBUM PHOTO (Script)
ANTI SPAM
APICULTURE
BAECKEOFFE
BREDELE
BUCHE DE NOEL
C++
CADRE
CASSOULET
CHARLOTTE AUX FRUITS
CODAGE ADRESSES MAIL
CODE 2 DE 5 ENTRELACE
CODE 3 DE 9
CODE 128
CODE PDF417
CODES BARRE
CODE POSTAL
CODES VIDEOTEXT
COLOMBO DE PORC
CONFITURES
CONGOLAIS
CORNICHONS AU VINAIGRE
COUARAIL
CREMES
CRUMBLE
CYBERMUT
DADANT
DATAMATRIX
DDE
DOMBRE
DOUBLE NAT
DYNDNSUPDATE
EAN 13
EAN 128
ELECTRONIQUE
ENVOI DE SMS
ESPACE MEMBRE
EURO
EXEMPLES VB6
FAR
FARCE
FAVORIS
FONCTIONS
FONCTIONS EN C++
GATEAU ROULE
GRATIN LORRAIN
GUACAMOLE
IMPRIMANTES RESEAUX
INSTANCE UNIQUE
KIT VB4
LANGSTROTH
LIQUEUR
MADELEINES
MAISONS
MAQUEREAUX AU VIN BLANC
MAQUEREAUX (Rillettes)
MARINADES
NMEA
NOUGATINE
PAIN
PATE A TARTE
PDF417
PHP
PIC
PLANS DE MAISON
PLANTEUR
POMMES
POULET COCO
PROCEDURES
PROGRAMMATION
RATATOUILLE
RECETTES DE CUISINE
RESSOURCES RESEAUX
RHUBARBE
R.I.B.
RILLETTE DE MAQUEREAUX
ROUTINES
RUCHE
SAUMON EN CROUTE
SCRIPTS
SITES
SLICE
SMS
SOUPE DE COURGE
TABLE PERIODIQUE
TARTE
TATIN (Tarte)
TARTIFLETTE
USB
VIDEOTEXT
VISUAL BASIC
VOIRNOT
WNTIPCFG

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The Datamatrix code


Version francaise

This code is part of 2 dimentional code family, it can encode up to 2335 characters on a very small surface. The encoding is done in two stages : first the datas are converted to 8 bits "codeword" (High level encoding) then those are converted to small black and white squares. (Low level encoding) Moreover an error correction system is included, it allows to reconstitute badly printed, erased, fuzzy or torn off datas. In the continuation of this talk, the word "codeword" will be shortened into CW.

The general structure.

A 2 x 2 regions code :

Low level encoding.

High level encoding.

Errors detection and correction.

Bar code making.

Since we can create the bar code pattern it remains us to draw it on the screen and to print it on a paper sheet. Two approaches are possible :

It seems that there's no free datamatrix barcode font on the net. I've decided consequently to draw this font and to propose it for download. Since each symbol have an even row number and an even column number, I put in each character of the font 4 modules (2 rows and 2 columns). In this manner we have 16 combinations assigned to the 16 first capital letters.
If we give a value at each dot of this 2 x 2 matrix like this :

1

2

4

8

the ASCII value of the character associated to a given matrix is the sum of each dot value + 65 (65 = A = no dot !)

The " datamatrix.ttf " font

This font contains the 16 character A (ASCII : 65) to P (ASCII : 80)

Copy this file
in the font directory,
often named :
C:\WINDOWS\FONTS

Encoding a datamatrix barcode

The software will evolve with 4 steps :

Because of the interaction between the different compaction modes it's difficult to make a 100% optimization. Thus the software will split the string into "parts" having the type "numeric", "text" or "byte" afterwards it will change some parts for an other mode if the overload due to switch CWs is greater than the compaction gain. We'll can't make allowance for all the parameters like paddings, ...

 

 

 WORK IN PROGRESS

 

A small program to test all that

 

 

 

 WORK IN PROGRESS

 

 


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