On-chain 8x8 bitmap svg packed into a single 32 byte storage slot. By packing the bitmap into a single storage slot, we can dramatically reduce gas consumption.
Each bitmap has 64 squares, with each square corresponding to a 4 bit color.
Consider the following bitmap: 0x7624778dedc75f8b322b9fa1632a610d40b85e106c7d9bf0e743a9ce291b9c63. We can see how each 4 bit value is assigned to a square according to the above color pallet.
| 7 | 6 | 2 | 4 | 7 | 7 | 8 | d |
|---|---|---|---|---|---|---|---|
| e | d | c | 7 | 5 | f | 8 | b |
| 3 | 2 | 2 | b | 9 | f | a | 1 |
| 6 | 2 | 3 | a | 6 | 1 | 0 | d |
| 4 | 0 | b | 8 | 5 | e | 1 | 0 |
| 6 | c | 7 | d | 9 | b | f | 0 |
| e | 7 | 4 | 3 | a | 9 | c | e |
| 2 | 9 | 1 | b | 9 | c | 6 | 3 |
And a more intentionally arranged bitmap: 0x000000000dd0bb000dd2bb20002202200ff077000ff277200022022000000000
For the initial implementation we went with an 8x8 grid of 4 bit colors, but we can do this with different grid sizes and color profiles as long as they are inversely related. For example, we can do the following variations:
- 4x4 grid of 8 bit colors (256 different colors)
- 8x8 grid of 4 bit colors (16 different colors)
- 16x16 grid of 2 bit colors (4 different colors)
- 32x32 grid of 1 bit colors (2 different colors)
We can also play around with various color pallets, use an additional slot, etc..
Wanna implement a different variation? Submit a PR!