Auxiliary File Formats
These are the formats of some auxiliary files used by .

Check Format Files (*.chk)

Overview
The check format file is used to tell how to print a check or checks onto a page of paper. This file first describes the overall layout of a page (number of checks, orientation, etc) and then describes the layout of the specific items on a single check. The file is organized as a typical Key/Value file used by many applications. Keys/values pairs are grouped into sections that begin with the group name enclosed in square brackets.
looks for check format files in two different locations when you bring up the check printing dialog. The first location is typically /usr/share/gnucash/checks, where check files distributed with the application can be found. The second location is the user private checks [1] directory. Users may add check formats at any time (even while is running) simply by dropping a new *.chk file in this directory. The next time the check printing dialog is opened the new check format will appear in the list of available check formats.
[1] Up to 2.6.21 it was checks
Printing functions differently depending on the version of GTK that is installed on your system. When is using a version of GTK prior to 2.10 all offsets are measured from the lower left corner of the page or check. When using GTK 2.10 or later, all offsets are measured from the upper left corner of the page or check.

Example file
A typical check file is presented below. The contents of this file will be described in the next sections.

[Top]
Guid = 67b144d1-96a5-48d5-9337-0e1083bbf229
Title = Quicken/QuickBooks (tm) US-Letter
Rotation = 0.0
Translation = 0.0;4.0
Show_Grid = false
Show_Boxes = false

[Check Positions]
Height = 252.0
Names = Top;Middle;Bottom

[Check Items]
Type_1 = PAYEE
Coords_1 = 90.0;102.0;400.0;20.0

Type_2 = AMOUNT_WORDS
Coords_2 = 90.0;132.0

Type_3 = AMOUNT_NUMBER
Blocking_Chars_3 = true
Coords_3 = 500.0;102.0

Type_4 = DATE
Coords_4 = 500.0;67.0

Type_5 = NOTES
Coords_5 = 50.0;212.0

Field Descriptions

Top Group
This section of the check file describes the overall layout of a page of checks (or check) that goes into the printer.

Overall Page Description Fields
Name	Type	Required	Description
Guid	string	mandatory	The guid is used to uniquely identify a check format to . It must be unique across the entire set of application supplied and user supplied check formats. If you copy an application check file as the basis of your own check format, you must change this value. The uuidgen program may be used to generate these identifiers.
Title	string	mandatory	The title is used to uniquely identify a check format to the user. This value is presented verbatim in the check format list of the check printing dialog. If you copy an application check file as the basis of your own check format, you should change this value. The title may be any utf-8 string.
Font	string	optional	If supplied, this is the default font used to print all text items on this check. This field can contain any string that is acceptable by gtk as a font specifier. If this field is omitted, the default font is the font specified in the preferences dialog. A typical string would be sans 12.
Blocking_Chars	boolean	optional	If supplied, this is the default used when printing all TEXT items on this check. When set to true, will print *** before and after each text field on the check. Blocking characters are printed to protect check fields from alteration. For example, the amount field may be printed as ***100.00***
DateFormat	boolean	optional	If supplied, this is the default used when printing all DATE items on this check. When set to true, will print the format of the DATE in 8 point type, centered and below the actual DATE. For example DDMMYYYY.
Rotation	double	optional	This value specified the rotation of the entire page (in degrees) around the origin point. For gtk versions prior to 2.10, the origin point is in the lower left corner of the page and rotation values increase in the counter-clockwise direction. For gtk version 2.10 and later, the origin point is in the upper left corner of the page and rotation values increase in the clockwise direction. Rotation of the page is applied before translation.
Translation	list of 2 doubles	optional	These values specify the x and y translation of the entire page (in points) relative to the origin point. For gtk versions prior to 2.10, the origin point is in the lower left corner of the page and translation values increase moving up and to the right. For gtk version 2.10 and later, the origin point is in the upper left corner of the page and translation values increase moving down and to the right. Rotation of the page is applied before translation.
Show_Grid	boolean	optional	If this value is set to true then will draw a grid on the page, starting at the origin with the lines spaced every 50 points. This can be helpful when creating a check format file.
Show_Boxes	boolean	optional	If this value is set to true then for each item where the width and height have been specified, will draw a box showing location and maximum size of that item . This can be helpful when creating a check format file.
The Blocking_Chars and DateFormat options are defined for all check formats in Edit->Preferences->Printing. It is recommened that these global options be set to false (the default), and that the options be set for individual Check Items as described below.

Check Positions Group
This group of items specifies how multiple checks are laid out on the same sheet of paper, and gives names to each of these check locations so that a user can specify which check location that should print. This entire group of key/value pairs is optional, and should be omitted if the format file only specifies a single check per page of paper.

Multiple Checks Per Page Fields
Name	Type	Required	Description
Height	double	mandatory	This field specifies the height of a single check on the page. If there are multiple checks per page then this item is mandatory. If there is only a single check per page, this entire section should be omitted.
Names	list of strings	mandatory	This field specifies the names of the check locations that can be printed on each page. These names represent the check positions starting from the top of the page and moving downward. The names are presented verbatim in the check position list of the check printing dialog. A typical value for this field is "Top;Middle;Bottom", but it could also be "First;Second;Third" or any other set of strings that clearly identify the check locations. If there are multiple checks per page then this item is mandatory. If there is only a single check per page, this entire section should be omitted.

Check Items Group
This section specifies the individual items that are printed on the check. There is no limit to the number of items that may be present in this section, and any given type of item can be repeated multiple times. This allows for the printing of checks that have a side stub, or for the one-per-page business checks that have both the check and multiple check stubs on the same page. For example, to print the payee name on a business check and on both stubs, simply specify three payee items with differing print coordinates.
Each key names in this section explicitly includes the item number to which it applies. E.G. The key named Type_1 applies to the first item to be printed, and the key Coords_3 applies to the third item to be printed. Item numbers start at one and increase sequentially. Any gap in the numbering sequence is interpreted by as the end of the item list. Items are printed in the order of their item numbers, not in the order in which they appear in the file.
Each item specified must include a type declaration. The rest of the parameters for that item depend upon the particular type of that item. See Individual Check Item Types for a list of valid item types and their required parameters.

Individual Check Item Fields
Name	Type	Required	Description
Type_n	string	mandatory	This field specifies the type of a single item to be printed on a check. See Individual Check Item Types for a list of valid item types.
Coords_n	list of 2 or 4 doubles	mandatory	This field specifies the coordinates where the item should be placed on a check, and optionally also specifies the width and height of the item. The numbers in order are the X and Y offset of the lower left corner of the item, and optionally the width and height of the item. If the width is supplied then the height must also be supplied, so this field will always contain two or four numbers. For gtk versions prior to 2.10, the origin point is in the lower left corner of the page and translation values increase moving up and to the right. For gtk version 2.10 and later, the origin point is in the upper left corner of the page and translation values increase moving down and to the right. Regardless of whether the origin is at the top or the bottom of the page, the coordinates always specify the lower left point of the item.
Font_n	string	optional	If supplied, this is the font used to print this specific text item. This field can contain any string that is acceptable by gtk as a font specifier. If this field is omitted, the default font is the font specified in the Top section of the check description file, or if that was omitted the font specified in the preferences dialog. This field is only recognized when using gtk version 2.10 or later.
Align_n	string	optional	If supplied, this is the alignment used to print this specific text item. This field must contain one of the strings left, center or right. If this field is omitted, the text will be left aligned. This field is only recognized when using gtk version 2.10 or later.
Text_n	string	optional	This field is only used when the item type is TEXT. It specifies the utf-8 text that should be printed on the check.
Filename_n	string	optional	This field is only used when the item type is PICTURE. It specifies the filename of the image that should be printed on the check. The string may specify either an absolute path name or as a relative path name. If a relative path name is specified, first looks in in the application check format folder (typically /usr/share/gnucash/checks ) for the image file, and if it is not found there then it looks in the user private checks directory for the image. This field is only recognized when using gtk version 2.10 or later.
Blocking_Chars_n	boolean	optional	If supplied, this will set the print Blocking_Chars option for this item.
DateFormat_n	boolean	optional	If supplied, this will set the print DateFormat option for this item.
These are the individual items that can be printed on a check. All items require the coordinates on the page where the item should be printed. The majority of these items result in text being printed on the page, and these items may have individual font and alignments specified. For example, the numerical amount of a check could be printed right justified while everything else is printed left justified. Other types may have unique parameters.

Individual Check Item Types
Name	Required Fields	Optional Fields	Description
PAYEE	Coords	Font Align Blocking_Chars	This type value tells to print the check payee name at the specified coordinates.
DATE	Coords	Font Align Blocking_Chars DateFormat	This type value tells to print the check date at the specified coordinates.
NOTES	Coords	Font Align Blocking_Chars	This type value tells to print the transaction notes field at the specified coordinates.
CHECK_NUMBER	Coords	Font Align Blocking_Chars	This type value tells to print the check number at the specified coordinates. The check number reflects the book option selection under File Properties for number source (transaction number or anchor-split action - see Use Split Action Field for Number in the Book Options section of the Manual).
MEMO	Coords	Font Align Blocking_Chars	This type value tells to print the split memo field at the specified coordinates.
ACTION	Coords	Font Align Blocking_Chars	This type value tells to print the split action field at the specified coordinates. However, the printed field reflects the book option selection under File Properties for number source (transaction number or anchor-split action - see Use Split Action Field for Number in the Book Options section of the Manual). If number source for the book is specified as anchor-split action, this field will instead print the transaction number field.
AMOUNT_WORDS	Coords	Font Align Blocking_Chars	This type value tells to print the check amount in words at the specified coordinates. The amount will appear similar to the string "One thousand, two hundred thirty four and 56/100".
AMOUNT_NUMBER	Coords	Font Align Blocking_Chars	This type value tells to print the check amount in numbers at the specified coordinates. The amount will appear similar to the number "$1,234.56".
ADDRESS	Coords	Font Align Blocking_Chars	This type value tells to print the address at the specified coordinates.
SPLITS_ACCOUNT	Coords	Font Align Blocking_Chars	This type value tells to print the account names for each split entry stating at the specified coordinates. See the note on splits printing.
SPLITS_AMOUNT	Coords	Font Align Blocking_Chars	This type value tells to print the amount for each split entry stating at the specified coordinates. Amounts are printed with currency symbols. See the note on splits printing.
SPLITS_MEMO	Coords	Font Align Blocking_Chars	This type value tells to print the memo text for each split entry stating at the specified coordinates. See the note on splits printing.
TEXT	Coords, Text	Font Align Blocking_Chars	This type value tells to print an arbitrary string at the specified coordinates. The string to be printed is specified with the Text_n key.
PICTURE	Coords, Filename	(none)	This type value tells to print an image at the specified coordinates. The image to be printed is specified with the Filename_n key. This type is only recognized when using gtk version 2.10 or later.
SPLIT items include all split entries for the transaction except for the split that applies to the current account register (referred to as the anchor-split). This is usually the last split listed when splits are displayed in the register. The coordinate location defines the lower left location for the split information.

Creating Check Format Files
Creating your own check format file is a fairly simple task. The easiest way to start is to copy an existing check format file from the application directory (typically /usr/share/gnucash/checks) to the directory checks. Make sure to change the guid so the new file will be accepted by gnucash, and change the title to something descriptive. Then change or add individual item fields as necessary. You can also create a new check file by clicking the Save Format button on the Custom format page of the check printing dialog.
Key names are case sensitive. If you are having problems with a check format file, ensure that all key names have capital letters as documented above.