Today lets talk about you can format report elements and what options our Pentaho Report Designer offers you.
Anatomy of Elements
Elements can be grouped into two classes. Text elements transform data into a textual representation. Labels, String-Fields, Message-Fields and Number- and Date-Fields are examples of these fields. Graphical elements produce a image to display the data. Charts, Sparklines or Image-Fields are examples for this class of elements.
A report element in Pentaho Reporting consists of style information and attributes. Most styles and attributes can be provided either statically or can be calculated by a function. The static properties are called “design time properties”. The calculated properties are called “runtime properties”.
Attributes control the element’s behaviour and how data is processed for displaying in the element. Examples for this are format-strings, rich-text processing and so on. Style properties control the visual appearance of the data printed.
With the Pentaho Report Designer you will find many formatting options that you can find in other text processor or graphical programs.
All elements share some common properties:
- visible: Defines whether a element is shown on the final print out. Visibility is mostly used as runtime property instead of being specified at design time.
- min-width, min-height: The width and height of an element define how much space a element takes on the paper. It also controls how many lines of text can be printed and how many characters fit onto each line. The size is either given in percentages (of the width and/or height of the element) or in points (1/72th of inches).
- x, y: The position of the element if placed into a canvas element. The position is either given in percentages (of the width and/or height of the element) or in points (1/72th of inches).
- dynamic-height: Dynamic height is a flag you can set to let the element expand its height to match the content you attempt to print.
- various border properties: Allows you to draw a border around the element. You can define the border of the currently selected element very easily by using the menu option “Format->Border..”
- padding: Padding allows you to insert some space between the edge of the element (where the borders sit) and the content printed in the element. The padding size is given in points (1/72th of inches).
- text-color, background-color: Defines the element’s foreground and background colours.
For text elements, the most common style you are going to change is probably the font properties.
- font-name: Defines the font name. The font must be available, or a default font is used instead. This is especially important if you intend to publish the report to a server, which may not have the same fonts as you installed.
- font-size: Padding allows you to insert some space between the edge of the element (where the borders sit) and the content printed in the element.
- bold, italics, underline, strike-through: Various flags controlling the appearance of the text
- embedded: This flag is only useful for PDF exports. It controls whether the font is embedded into the PDF document. Only TTF-fonts can be embedded and not all fonts allow you to embed them.
- h-align, v-align: Positions the text within the element.
Graphical elements have different properties based on what sort of element you are dealing with.
- scale, aspect-ratio: Defines whether the shape will scale up or down to fit the element’s bounding box. If “keep-aspect-ratio”
- fill-element: Defines whether the shape will be filled. This has no effect on lines. Elements will be filled with the colour defined in fill-color
- draw-outline: Defines whether the shape outline will be drawn. The outline will be drawn with the colour defined in text-color
: Defines the stroke that is used to draw the outline of the shape.
Most of the attributes for elements are advanced properties and not required to actually get a basic report up and running. So I will concentrate on the ones that really matter:
- value: The static value that should be printed. If this is defined,
- field: The name of the field from the reporting engine reads the value. If a value is given in the “value” attribute, that static value will be used and the field will be ignored.
if-null: A static value that is printed if the field would evaluate to
- data-format: A flag that defines whether the element will update its format string from the meta-data given by the data source.
- style-format: A flag that defines whether the element will update its style properties from the meta-data given by the data source.
- show-changes: If this flag is set to true, the element will only print if the value has changed from the previous value. The element will always print if it is the first element in the group or on the page.
Message-, Date- and Number-Fields
- format: Defines the format string. To make number fields align correctly, ensure that your format specifies a fixed set of decimals in the format string and that you right-align the field in the style options.
Armed with this knowledge, formatting elements in a report should no longer be a daunting task. “Be fruitful and multiply your reports, and fill the sheets and subdue it; and have dominion over your data and over the numbers of the accounting and over every piece of information that moves in your company.”