Presets

What a preset is

A preset is a ready-made table style that the library generates from one accent colour A. It produces five layers, applied at the lowest level of the respective cascades:

Layer	Applied to
title	the title row
header base	every header cell
body base	every data cell
body odd	data cells of odd rows
body even	data cells of even rows

Tones are derived from A by mixing it with white (tint(A, f), where f is the fraction of white, from 0 to 1) or with black (shade(A, f), fraction of black). Text placed on a filled background is white or black, whichever has the higher contrast ratio with the background according to WCAG (contrast(X)). The two ratios are equal at a relative luminance of about 0.18, so mid-tone backgrounds get black text.

The presets

Constant	Meaning
`INHERIT`	Uses the application default preset. Valid only on a sheet class, not as the application default itself.
`NONE`	No preset: only the declared styles apply.
`LIGHT`	Light table.
`MEDIUM`	Medium table.
`DARK`	Dark table.

Layers of each preset

Layer	`LIGHT`	`MEDIUM`	`DARK`
Title	bold, 14 pt, text `shade(A, 0.25)`	same as `LIGHT`	same as `LIGHT`
Header base	bold, text `shade(A, 0.25)`, bottom border `MEDIUM` colour `A`	bold, fill `A`, text `contrast(A)`	bold, fill `shade(A, 0.5)`, text `contrast(shade(A, 0.5))`
Body base	bottom border `THIN` colour `tint(A, 0.75)`	all borders `THIN` colour `tint(A, 0.6)`	nothing
Body odd	fill `tint(A, 0.85)`	fill `tint(A, 0.8)`	fill `A`, text `contrast(A)`
Body even	nothing	nothing	fill `shade(A, 0.25)`, text `contrast(shade(A, 0.25))`

In words:

LIGHT. Header with bold dark accent text and a medium accent line below it; a thin light accent line below each data row; very light accent fill on odd rows and no fill on even rows. Suited to printed reports and dense tables.
MEDIUM. Header with accent fill and bold contrasting text; a thin light accent grid around every data cell; light accent fill on odd rows and no fill on even rows. The most “spreadsheet-like” preset, suited to operational exports.
DARK. Header with dark accent fill and bold contrasting text; no lines; accent fill with contrasting text on odd rows, and darker accent fill with contrasting text on even rows. High visual impact, suited to dashboards and short summary tables.

In every preset the title is bold, 14 pt, with dark accent text, and only the title layer applies to the title.

Computed colours for common accents

The table shows the colours that each preset actually writes for a few accents. #4472C4 is the default accent.

Accent `A`	`shade(A,0.25)` (title, LIGHT header text, DARK even fill)	`tint(A,0.75)` (LIGHT row line)	`tint(A,0.85)` (LIGHT odd fill)	`tint(A,0.6)` (MEDIUM grid)	`tint(A,0.8)` (MEDIUM odd fill)	`shade(A,0.5)` (DARK header fill)	Text on `A`	Text on DARK even
`#4472C4` (default blue)	`#335693`	`#D0DCF0`	`#E3EAF6`	`#B4C7E7`	`#DAE3F3`	`#223962`	white	white
`#1F4E79` (dark blue)	`#173A5B`	`#C7D3DE`	`#DDE4EB`	`#A5B8C9`	`#D2DCE4`	`#10273C`	white	white
`#70AD47` (green)	`#548235`	`#DBEAD1`	`#EAF3E3`	`#C6DEB5`	`#E2EFDA`	`#385624`	black	black
`#FFC000` (amber)	`#BF9000`	`#FFEFBF`	`#FFF6D9`	`#FFE699`	`#FFF2CC`	`#806000`	black	black
`#C00000` (red)	`#900000`	`#EFBFBF`	`#F6D9D9`	`#E69999`	`#F2CCCC`	`#600000`	white	white

The DARK header text is white for all five accents.

Choosing the preset and the accent

Where	How	Scope
Sheet class	`@ExcelSheet(preset = ..., accentColor = ...)`	that sheet class
Application, builder	`SheetsmithDefaults(..., preset, accentColor)`	every sheet class that declares `INHERIT` and no accent
Application, Spring Boot	`sheetsmith.preset`, `sheetsmith.accent-color`	same

Resolution: the effective preset is the class preset, or the application preset when the class declares INHERIT. The effective accent is the class accent, or the application accent when the class declares none. A class can therefore inherit the preset and set its own accent, or the opposite.

// The whole application uses LIGHT with the corporate blue...
new SheetsmithDefaults("dd/mm/yyyy", "dd/mm/yyyy hh:mm", "", TablePreset.LIGHT, "#1F4E79");

// ...this report keeps LIGHT but uses green...
@ExcelSheet(accentColor = "#2E7D32")

// ...and this one uses no preset at all.
@ExcelSheet(preset = TablePreset.NONE)

Adjusting a preset

The preset is the lowest level of every cascade, so any declared style overrides it attribute by attribute. Common adjustments:

@ExcelSheet(preset = TablePreset.MEDIUM,
        header = @HeaderStyles(base = "header"),
        body = @BodyStyles(even = "even"))
@ExcelStyle(name = "header", align = Align.CENTER, wrapText = Toggle.TRUE)   // keeps fill and bold, adds alignment
@ExcelStyle(name = "even", fillColor = "#F2F2F2")                           // grey fill on even rows

// Remove the zebra on one column, keep it elsewhere
@ExcelColumn(header = "Notes", order = 90, styles = @ColumnStyles(base = "plain"))
String notes;
// ...
@ExcelStyle(name = "plain", fillPattern = Fill.NO_FILL)

// Remove the MEDIUM grid from the first column only
@ExcelSheet(preset = TablePreset.MEDIUM, body = @BodyStyles(firstColumn = "no-grid"))
@ExcelStyle(name = "no-grid", border = Border.NONE)

Presets and the outer frame

The outer frame sits above the preset. With MEDIUM, for example, outerBorder = Border.MEDIUM thickens the external edges of the grid while the internal lines stay thin. With LIGHT, the frame closes the table on the sides, which the preset leaves open.

Visual examples

Choose an accent to see how each preset colours the same table. The colours are computed with the same rules as the library.

Accent colourYour colour

`TablePreset.LIGHT`

Thin accent lines and a very light zebra. Suited to printed reports and dense tables.

	A	B	C	D
1	Customers
2	Code	Name	Customer since	Revenue
3	C-0041	Northwind Supplies	12/03/2019	184,250.00
4	C-0057	Blue Harbor Ltd	01/09/2020	97,410.50
5	C-0102	Greenfield Foods	23/06/2021	211,900.00
6	C-0118	Atlas Engineering	15/01/2023	58,075.25
7	C-0131	Riverside Clinic	04/11/2024	33,640.00

`TablePreset.MEDIUM`

Filled header and a light grid. The most spreadsheet-like preset, for operational exports.

	A	B	C	D
1	Customers
2	Code	Name	Customer since	Revenue
3	C-0041	Northwind Supplies	12/03/2019	184,250.00
4	C-0057	Blue Harbor Ltd	01/09/2020	97,410.50
5	C-0102	Greenfield Foods	23/06/2021	211,900.00
6	C-0118	Atlas Engineering	15/01/2023	58,075.25
7	C-0131	Riverside Clinic	04/11/2024	33,640.00

`TablePreset.DARK`

Dark header and strong alternating fills. For dashboards and short summary tables.

	A	B	C	D
1	Customers
2	Code	Name	Customer since	Revenue
3	C-0041	Northwind Supplies	12/03/2019	184,250.00
4	C-0057	Blue Harbor Ltd	01/09/2020	97,410.50
5	C-0102	Greenfield Foods	23/06/2021	211,900.00
6	C-0118	Atlas Engineering	15/01/2023	58,075.25
7	C-0131	Riverside Clinic	04/11/2024	33,640.00