Using CC65 tgi_bar - i have created a demo to show how large scaled fonts can be drawn on the C64 screen. drawstring(characterarray, inputstring, startXpos, startYpos, scalefactor);

Functions:

drawstring: This function iterates over an input string, manipulating the starting X and Y positions, and subsequently draws characters across the screen. However, it's worth noting that it might scramble the screen if drawing near the screen's edges or bottom.

drawchar: Responsible for handling an 8x8 grid of data for a single character. Based on the value of the scalefactor, it either prints an 8x8 grid for scalefactor - 1 or, for scalefactor - 4, draws a larger 32x32 sized character on the screen. This is achieved using the tgi_bar function, which employs a rapid fill method utilizing a character block, known to be faster than setting pixels.

findcharindex: This function is tasked with converting the current character string slice and then returning the appropriate index position.

where to get the font

i used this one as it looked nice

• https://github.com/dhepper/font8x8/blob/master/font8x8_basic.h

The font array looks like this in the code

char alphabet[19][8] = {
{ 0x30, 0x78, 0xCC, 0xCC, 0xFC, 0xCC, 0xCC, 0x00}, // A
{ 0xFC, 0x66, 0x66, 0x7C, 0x66, 0x66, 0xFC, 0x00}, // B
{ 0x3C, 0x66, 0xC0, 0xC0, 0xC0, 0x66, 0x3C, 0x00}, // C

each row is 8 bits of information, and there are 8 rows. this gives us the 8x8 chararacter

I wrote a tool to horizontally transpose the bits of a hex 8x8 character font

An example for the letter B using font_endian_conv.py python3 font_endian_conv.py infile.txt outfile.txt

• cant recall if you need to add on curly braces or not but it does flip the bits correctly

demo

a demo of using tgi_bar call to draw scaled fonts on the C64 screen