GenerateASCII creates a 2D ASCII art representation of the contribution data.

Represents days with no contributions.

67-100% intensity.

1-33% intensity.

34-66% intensity.

Represents future dates.

GridWidth defines the standard width for the ASCII output.

HeaderTemplate contains the ASCII art header for the output.

33% of max contributions.

66% of max contributions.

Block character sets for different contribution levels.

Middle blocks (intermediate layers).

Block character sets for different contribution levels.

High intensity peak.

Lower intensity peak.

Medium intensity peak.

ErrInvalidGrid is returned when the contribution grid is invalid.