Introduction

This document lists the attributes associated with each type of data object and display object for the benefit of anyone writing or editing a picture definition file. Note that, rather than create a picture definition file from scratch, it is probably much easier to set up a display within CCP4mg, save a picture definition file and edit it.

There are some attributes which are common to all data objects and display objects and these are described first.

Data Object Attributes

Display Object Attributes

MolData

[1.0,0.0,0.0,0.0,
 0.0,1.0,0.0,0.0,
 0.0,0.0,1.0,0.0,
 0.0,0.0,0.0,1.0 ]

MolDisp

selection_parameters keys

selection_parameters is a dictionary attribute of a MolDisp object which should provide sufficient information to correctly initialise the selection menu on the MolDisp GUI. The selection attribute, on its own, is enough to define which atoms are displayed. The most important item in the dictionary is the select key which indicates which selection mode is being applied. Dependent on the value if the select key, various other items will be necessary in the dictionary.

colour_parameters

style_parameters

SurfaceDispObj

HBonds and Contacts

Annotation

AnisoU

MapData

MapDisp

Crystal

2D Objects

Images and legends are grouped together on the GUI Display Table and are treated as display objects.

Image

A 2D image loaded from an picture file such as .png or .jpg.

Legend

VectorsData

VectorsDispobj

ParamsManager

A generic ParamsManager class is used in CCP4mg to handle many of the Preferences interfaces. The ParamsManagers are listed in the Save options interface to be selected for output to the picture definition file. An example of a ParamsManager in a picture definition file:

ParamsManager(
          name = 'surface_drawing_style',
          resolution_delta = 20.0,
          dot_spacing = 0.01,
          blend_edges = 1          )

The ParamsManager should always have a name attribute which identifies which set of preferences it handles. Some types of data object or display object can have a ParamsManager associated with then to handle the options specifically for that object. For example a SurfaceDispObj can have an associated 'surface_drawing_style' ParamsManager which has the same attributes as the global 'surface_drawing_style' ParamsManager and has a name which conventionally is 'surface_drawing_style_SurfaceDispObj name'. To tie the display object to the ParamsManager the SurfaceDispObj object needs to have an attribute drawing_style with the value of the ParamsManager name.

ColourSchemeManager

Colours

The standard colour names that are always defined within CCP4mg: blue, red, green, grey, yellow, magenta, royal blue, cyan,coral,pale green,pink,lemon,purple,tan,black. The colour name 'complement' will give the colour which complements the background colour (e.g. for black background gives white).

There is an option on the Picture Definition File Save options interface to save Colour definitions. To define a new colour in the picture definition file looks like this:

Colours ( yuck = [ 0.5 , 0.5, 0.5 , 1.0 ] )

The arguments to Colours are the names of the colours with values that are a list of four floats. The first three items in the list are the proportion of red, green and blue components in the colour in the range 0.0 to 1.0. The forth value is an 'alpha' value which should be set to 1.0 (or can be excluded). It is possible, but possibly anti-social, to redefine the standard colours is similar format:

Colours ( red = [ 0.0, 1.0, 0.0 , 1.0 ],
          green = [ 0.0, 0.0, 1.0, 1.0],
          blue =  [ 1.0, 0.0, 0.0 , 1.0 ]  )

View

The View attributes can determine the orientation of the display. The attributes are:

Notes on some common attributes

Filenames

Fonts

Several types of object have a font attribute. It is a dictionary and all the items have values which are strings. CCP4mg supports some built-in fonts that are have names beginning Fast .. and those font families that are available on the computer system on which it is run. Beware that available fonts are very dependent on operating system. For the built-in fonts the size, slant and weight attributes are ignored. The dictionary keys are