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55 lines
1.8 KiB
Text
55 lines
1.8 KiB
Text
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VGA Font File Formats
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=====================
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We only deal with 8x8 fonts with 256 characters, so different formats aren't described here.
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1. The binary format (*.bin)
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----------------------------
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A binary font file is always 2048 bytes in size.
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These bytes are divided into 256 characters, so every character is 8 bytes large.
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Each byte represents a character row. Consequently, each column is represented by one bit. The most-significant bit contains the pixel of the first column from the left.
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Example:
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We want to get the pixel in the third column of the second row of the seventh character.
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We assume you loaded the binary font file completely into a byte array called FontBits.
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// All indexes need to be zero-based
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UINT uCharacter = 6;
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UINT uRow = 1;
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UINT uColumn = 2;
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UCHAR uBit;
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// uBit will either contain 0 (0-bit is set) or 128 dec, 0x80 hex (1-bit is set) now
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uBit = FontBits[uCharacter * 8 + uRow] << uColumn & 0x80;
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2. The PC Screen Font Version 1 format (*.psf)
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----------------------------------------------
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A PC Screen Font Version 1 file is always 2052 bytes in size.
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It has the following structure:
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struct PSF1_FILE
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{
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UCHAR uMagic[2];
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UCHAR uMode;
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UCHAR uCharSize;
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UCHAR FontBits[2048];
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};
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* uMagic contains two magic bytes, which identify a PSFv1 file. These are:
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uMagic[0] = 0x36
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uMagic[1] = 0x04
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* uMode specifies special modes of the font.
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We only deal with fonts here, which don't have any special modes, so this value should be 0.
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* uCharSize specifies the size of a character.
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In our case, this needs to be 8.
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* Finally the FontBits array contains the font bits in the same format as described above.
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This way, it is very easy to convert a PSFv1 file to a binary *.bin file.
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- Colin Finck, 2008/02/01
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