img2sx

README

img2sx: Image 2 MSX converter

Simple image converter that converts images between the following formats:

• PNG
• SC2 (applies resize)
• TO DO: more formats

It's also a Go library to handle SC2 files as image.Image interface implementors.

Usage

img2sx -i <input_file> -opt <options> <output_file.png>

options. Comma-separated list:

• sc2 output:

crop: if source is larger than the image, it crops the destination image (default)
stretch: if source and dest file size are diferent, crops
aspect: if source and dest sizes are different, rescales keeping the aspect ratio

sh2 format

Shrinked sc2 format: it merges into one all the equal tiles. All the tables and names are optional, so you can have a single patterns table or no names table at all.

The format is:

• Header (4 bytes): SH2\n
• Indexes
  • Pattern table 1:
    • 1 byte, offset: end of header
    • number of tiles (8 bytes each) belonging to the pattern table 1 and color table 1
  • Pattern tables 2 and 3:
    • 1 byte, offset: end of the previous pattern tables
    • number of tiles belonging to pattern table 2 or 3 and color tables 2 or 3
    • if 0, it is a copy of Pattern table 1
  • Enabling name tables:
    • 1 byte, offset: end of pattern table 3
    • If 0, there is no name tables
    • If !0, it should read 256 bytes for each of the three name tables.
• Byte contents:
  • patterns for pattern table 1
  • colors for pattern table 1

Example: hex dump of a very simple file with 2 tiles per pattern table:

53 48 32 0A     <-- SH2\n header
02 02 02        <-- each pattern table has 2 tiles
01              <-- name tables are enabled
00 01 02 03 04 05 06 07    <-- data of pattern table 1 starts here (2 tiles * 8 patterns)
08 09 0A 0B 0C 0D 0E 0F
10 11 12 13 14 15 16 17    <-- data of color table starts here (2 tiles x 8 patterns)
18 19 1A 1B 1C 1D 1E 1F
20 21 22 23 24 25 26 27    <-- data of pattern table 2
28 29 2A 2B 2C 2D 2E 2F
30 31 32 33 34 35 36 37    <-- data of color table 2
38 39 3A 3B 3C 3D 3E 3F
40 41 42 43 44 45 46 47    <-- data of pattern table 3
48 49 4A 4B 4C 4D 4E 4F
50 51 52 53 54 55 56 57    <-- data of color table 3
58 59 5A 5B 5C 5D 5E 5F
60 61 62 63 64 65 66 67    <-- name tables start here (3 * 256 bytes)
68 69 6A 6B 6C 6D 6E 6F
70 71 72....

API

TO DO