Work done in clearing Bugs with Unicode Fonts that comes default with Ubuntu

உபுண்டு தளத்திலிருந்து

CLEARING BUGS IN ALREADY EXISTING FONT(TAM_MADURAM)

Step 1
Choose the TAMMaduram.ttf file which need to be modified Step 2
Open the TAMMaduram.sfd file in text editor which related to the .ttf file

Step 3
Open the already done .sfd file, like Lohit-Tamil.sfd

Step 4
Copy the lookup table from Lohit-Tamil.sfd file and paste it to our TAM_Maduram.sfd file(The lookup table starts from after OS2 line finished)

Step 5
After paste the lookup tables save the file as Maduram.sfd

This is the .sfd file of TAM Maduram after adding lookup tables. The colored lines are the lookup tables

Step 6
Now open the TAM_Maduram.ttf file through font forge which is need to be modified and its .sfd's lookup table is already changed and saved

Step 7
The bug in the TAM_Maduram font is the uni-code mapping is not good, now we change it.

Step 8
In this font the letter ki is located in the place of A and some other tamil letters are located in the place of english letters.

This is the TAMMaduram.ttf You can see the bug above i told.

The following are important steps to clear the bugs.

Step 9
First we change the Font info Elements->Font info

Step 10
Choose Names and change the font name as you like when you type the Font name the family name and name of humans are automatically take the font name

Step 11
Choose the Lookups. This is look like the following figure

Step 12
If the lookup tables are not visible here we add new lookup table through Add Lookup the screen is look like the following

Step 13
Change the Type as ligature substitution

Step 14
In the feature a drop down list is available from that we change feature. Here I explain one feature.From that drop down list choose Post Base Substitution after choose it in the Script(s) and Language(s) column three languages are come(DFLT(dflt) taml(dflt) latn(dflt))

Here we need only Tamil language so we delete (DFLT{dflt] latn{dflt})others

The lookup name is automatically changed as 'psts' Post Base Substitutions lookup 0. Now we change it as 'psts' Post Base Substitutions in Tamil lookup 0 because we change the Tamil font. Then press OK

Step 15
After adding the lookup table Add sub-table press OK

Step 16
Cut the Tamil letters which is occupied in the place of English letters and paste it to their proper uni-code places.

Step 17
Change the Tamil letters name also to relate their uni-code

Step 18
Next our goal is to create ligature(Adding two characters and create new character) For example to create Ku using ka and U that is Ku=ka+U. The following are steps to create ligature 1.Add the boxs which doesn't have unicode values. Encoding->Add Encoding slots. A message box appear like the following figure

2.How many slots we need enter the number in the text box

3.New boxes are created without unicode values

3.cut the glyph Ku where it is occupy another character's place

4.paste it in newly created box (using the above method)

5.Right click the box

4.Choose Glyph info

5.Change the uni-code name as Tam_Ku

6. The uni-code value as -1

7.Choose ligature

8.Here a table is available with two columns titled as Sub table and Source Glyph name

9.In the sub-table column a drop down list which has the lookup sub-tables already we add.

10.Choose the lookup sub-table which is apt to our ligature. Here I choose psts' Post Base Substitutions in Tamil lookup 0'

11.In the source glyph name column type the unicode name of which two glyphs need to be added and produce the new glyph For example uni0b95 uni0bc1 is for ku

12.Press OK

13.This way we create ligatures

Step19
From the file menu choose save the .sfd file. It is save with modification

Step20
From the file menu choose generate fonts the .ttf file is saved.That is font is generated

Step21
Open the terminal

Step22
First copy the modified font to .fonts folder if the .fonts folder is already created otherwise create the .fonts folder and type the following command if you save the .ttf file in Desktop cp Desktop/Maduram.ttf(your font name) .fonts/

Step23
Then type the following command fc-cache -f

Step24
Open the OpenOffice

Step25
Your font is available in the font names Step26
Type anything in Tamil and English in other fonts and select the all typed lines and change the font name as the modified font(Maduram)