BLIT identifier AS expression

The “BLITTING” is a data operation used in computer graphics in which several bitmaps are combined into one using a boolean (or mathematical) function. The operation involves at least two bitmaps: a “source” (or “foreground”) and a “destination” (or “background”), and other fields, called “masks” or something like that. The result may be written to a final bitmap, though often it replaces the “destination” field.

The pixels of each are combined bitwise according to the specified BLIT OPERATION (BOP) and the result is then written to the destination. The BOP is essentially a boolean formula, that can be written using BLIT instructrion. The most obvious BOP overwrites the destination with the source. Other BOPs may involve AND, OR, XOR, and other more complex operations.

  BLIT bop1 AS ( ( SOURCE ) AND ( DESTINATION ) )

See also the following example files:

• blit_basic_mask.bas

 Blt

• Atari (400/800)
• Atari XL/XE
• Commodore 128 (MOS 8502)
• Commodore 128 (Zilog Z80)
• Commodore 64
• Commodore 64+REU
• TRS-80 Color Computer
• TRS-80 Color Computer 3
• ColecoVision
• Amstrad CPC 664
• Dragon 32
• Dragon 64
• Thomson MO5
• Thomson MO5
• Olivetti Prodest PC128
• Commodore PLUS/4
• SEGA SC-3000
• SEGA SG-1000
• VG-5000
• Commodore VIC-20
• ZX Spectrum 48

If you have encountered a problem using this command, if you think there is a bug or the explanation is unclear, please open an issue for this keyword on GitHub. Thank you!