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usefont-pascal

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The way I implemented fonts in my programs was I created a picture - an array of numbers denoting colours₁ - of all the letters I would use. I then made some procedures that when I told it what letter to draw, it would look at the picture, find the letter and then draw it. The font I made looked like this:

           ABCDEFGHIJK9
           LMNOPQRSTUV7
           WXYZ01234568

Each letter being 4 by 6 pixels. I could Have drawn it bigger, but that is the size I wanted for my program. The next step was to get my program to look at the picture and know where every letter was. What I did was, I made a variable called CMAP (short for Character Map) that contained the string

' ABCDEFGHIJK9LMNOPQRSTUV7WXYZ01234568'

. If you look again at how the picture looked, you will notice that there are 12 characters on a line, but if you stick them all in a row, they look like my CMAP variable. So what I did was, I made my DrawLetter Procedure find the position of the letter in CMAP and then find the row (position DIV 12 - integer division) and the letter in the row (position Mod 12 - remainder) and then told it to start drawing at Row * 6 (Each letter is 6 pixels high) and column * 4 (Width = 4). For example, the number one is at position 31 in CMAP. Since CMAP contains ' ' in it, we need to minus 1. It is therefore at row: 30 Div 12 = 2 and column: 30 mod 12 = 6. Look at the grid of letters and you will see it is actually there!!! So let us apply all this to some code:

{We want to draw it at any XY on the screen with any font that is 4X6 and 
 is based on our CMAP}
Procedure WriteLetter4X6(X,Y : Integer; Lett : Char;Var Fnt : Pic);
{Type PIC is similar to type icon, just bigger - therefore, passed by 
 reference}
Var i, j, Temp, Row, Column : Integer; 
Begin
 Lett := Upcase(Lett);
 If Lett <> ' ' then 
 Row := (Pos(Lett,CMAP)-1) DIV 12; 
 Column := (Pos(Lett,CMAP)-1) MOD 12;
 For i := 0 to 3 do
   For j := 0 to 5 Do
     If Fnt[(X+Column*4)+i,(Y+Row*6)+j] <> 0 Then {0 = transparency colour 
                                                   of font}
              PutPixel(X+i,Y+j, Fnt[(X+Column*4)+i,(Y+Row*6)+j],VGA);
End;

And now that we have something to draw a letter, we can also draw a string. Look at the following procedure:

Procedure WriteString(x,y : Integer; MyString : String; Var Fnt : Pic);
Var i : Integer;
Begin
 For i := 1 to Length(MyString) do 
{Notice that it moves 4 pixels to the left between every leter => (i-1)*4}
  WriteLetter4X6(X+(i-1)*4,Y,MyString[i],Fnt);
End;

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Notes

₁) An example of what the letter 'A' looks like in the font is:

(0,0,0,0)
(0,0,1,0)
(0,1,0,1)
(0,1,1,1)
(0,1,0,1)
(0,1,0,1)

But that is what it looks like wen I extract it. In the font itself, it is saved next to the letter 'B' - as is shown in CMAP. Here is what it looks like:

(0,0,0,0,0,0,0,0)
(0,0,1,0,0,1,1,0)
(0,1,0,1,0,1,0,1)
(0,1,1,1,0,1,1,0)
(0,1,0,1,0,1,0,1)
(0,1,0,1,0,1,1,0)

This is a 8 by 6 block - two letters next to each other my type 'pic' is a 48 by 18 block - allowing the amount of letters in CMAP to be drawn. I made a small program that allowed me to draw these letters with the mouse onto a grid. I made it save it to a file and then read when I needed to access my fonts. I passed it to my write letter procedure to draw my letters. You will notice that both the letters are padded by '0' both on top and to the left - This is in order that I can write a string of letters and they wont run into each other.
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