Fonts

LOADBMP and FONTS

The LOADBMP command will load a color or monochrome bitmap image and display it at a specified location on the screen. This is handy for loading background images for games.

The FONT command can also be used to load custom designed graphic images and display them on the screen.

Loadable Fonts

This section describes the format of a font file that can be loaded using the FONT LOAD command.

A font file is just a text file containing ordinary characters which are loaded line by line to build the bitmap of each character in the font. Each character can be up to 64 pixels high and 255 pixels wide. Up to 255 characters can be defined.

The first non-comment line in the file must be the specifications for the font as follows:

height, width, start, end

Where ‘height’ and ‘width’ are the size of each character in pixels, ‘start’ is the number in the ASCII chart where the first character sits and ‘end’ is the last character. Each number is separated by a comma. So, for example, 16, 11, 48, 57 means that the font is 16 pixels high and 11 wide. The first character is decimal 48 (the zero character) and the last is 57 (number nine character).

The remainder of the lines specify the bitmap for each character.

Each line represents a horizontal row of pixels. A space means the pixel is not illuminated and any other character will turn the pixel on. If the font is 11 pixels wide there must be 11 characters in the line although trailing spaces can be omitted. The first line is the top row of pixels in the character, the next is the second and so on. If the character is 16 pixels high there must be 16 lines to define the character. This repeats until each character is drawn. Using the above example of a font 16×11 with 10 characters there must be a total of 160 lines with each line 11 characters wide. This is in addition to the specification line at the top.

A comment line has an apostrophe (‘) as the first character and can occur anywhere. A comment line is completely ignored; all other lines are significant.

The following example creates two small icons; a smiley face and a frowning face. Each is 11×11 pixels with the first (the smiley face) in the position of the zero character (0) and the frowning face in the position of number one (1). To display a smiley face your program would contain this:

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