class ZXUtils::Gallery

ZXUtils::Gallery. ↑

A program to load from tape and display various ZX Spectrum screen formats.

Supported ULAplus formats:

     format type      size      mode      colors   palette
/------------------^-------^------------^--------^---------\
| standard screen  |  6912 | screen 0   |     15 | default |
| standard plus    |  6976 | screen 0   |     64 | static  |
| standard HAM256  |  7680 | screen 0   |    256 | dynamic |
| high color       | 12288 | hi-color   |     15 | default |
| high resolution  | 12289 | hi-res     |      2 | bright  |
| hi-color plus    | 12352 | hi-color   |     64 | static  |
| hi-res plus      | 12353 | hi-res     |      2 | static  |
| hi-color HAM256  | 13056 | hi-color   |    256 | dynamic |
| stand. interlace | 13824 | screen 0/1 |     15 | default |
\------------------+-------+------------+------------------/

See: faqwiki.zxnet.co.uk/wiki/ULAplus#Extension_to_the_SCR_format

This gem provides a tool zxgallery that can be used to create a gallery .TAP file from .SCR files.

Example:

The following will produce test_gallery.tap file with the program and the .SCR files as TAP bytes.

zxgallery *.scr -o test_gallery.tap

This program can be also used as a library.

Example:

require 'zxlib/basic'
require 'zxutils/gallery'

class GalleryProg
  include Z80
  include Z80::TAP

  import              ZXUtils::Gallery
  screen              import_file "some_screen.scr"
  screen_end          label
end

program_code = GalleryProg.new 0xC000
start = program_code[:start]
screen = program_code[:screen]
screen_end = program_code[:screen_end]
program = ZXLib::Basic.parse_source <<-EOB
   1 DEF FN d(a,s)=USR #{start}: DEF FN l(a)=USR #{start}: DEF FN x()=USR #{start}
  20 BORDER 0: PAPER 0: INK 7: CLS
  30 RANDOMIZE FN d(#{screen},#{screen_end - screen})
  99 BORDER 7: PAPER 7: INK 0: CLS
9998 STOP: GO TO 10
9999 CLEAR #{0x6000 - 1}: LOAD ""CODE : PRINT USR #{start}: RUN
EOB
program.save_tap("gallery", line: 9999)
program_code.save_tap("gallery", append: true)

Constants

SCR_MAX_SIZE

The size of the largest .SCR file format supported.

Public Instance Methods

USR start click to toggle source
DEF FN x()=USR start
DEF FN l(a)=USR start
DEF FN d(a,s)=USR start

Gallery API.

This endpoint should be invoked from the ZX Basic directly via USR or indirectly via FN.

REM checks for hardware version: 48k or 128k and sets up appropriate delays for HAM256
LET detected=USR start: REM returns 48, 128 or 0 if could not determine

REM sets screen mode to 0, resets palette mode, clears screen attributes
RANDOMIZE FN x()

REM loads the file from the tape and returns its size
LET size=FN l(address): REM provide an address to load the screen at

REM displays the screen
RANDOMIZE FN d(address,size): REM provide an address of the screen and its size
# File lib/zxutils/gallery.rb, line 130
ns :start do
                    call  find_def_fn_arg            # is this an FN call with arguments?
                    jr    C, hw_detect_and_setup     # called directly via USR
                    jr    NZ, clear                  # called via FN ()
end