Render engine: supported features and expressions

VeloxFactory renders 
.jrxml templates with its own render engine: a pure-PHP implementation of JasperReports, based on the open source project JasperPHP and maintained by us as an independent fork. It needs no Java runtime, but it implements a defined subset of JasperReports rather than the full Java engine. This page lists exactly what that subset is, so you can design templates in Jaspersoft Studio that render the same way in VeloxFactory.
How to set up parameters, fields, resources and the query is described in Creating reports in Jaspersoft Studio. This page covers what happens inside the template: bands, elements, styles, expressions and formatting.
ℹ️ This page describes render engine 1.2. If a template behaves differently from what is described here, the render engine is the reference, not Jaspersoft Studio's preview. Always check a real rendering in VeloxFactory before you release a template.
Two rules for every template
Every band needs 
splitType="Stretch", including an explicit empty 
<background><band splitType="Stretch"/></background>.
Bands must follow the JasperReports XSD order: 
background, 
title, 
pageHeader, 
columnHeader, 
detail, 
columnFooter, 
pageFooter, 
lastPageFooter, 
summary. Jaspersoft Studio refuses to open a file with a different order.
Bands
Band
Behaviour
background
Printed once per page at the top edge, behind the content. Does not push other bands down.
title
Printed once on the first page. 
$F{...} shows the first data row.
pageHeader
Printed on every page. On the first page it follows the title.
columnHeader
Printed on every page that contains detail rows, also after a manual 
<break>.
detail
Printed once per data row. Grows with stretching text fields.
groupHeader / 
groupFooter
Printed whenever the value of the 
groupExpression changes.
columnFooter
Printed below the detail rows of a page.
pageFooter
Printed at the bottom of every page.
lastPageFooter
Replaces the 
pageFooter on the last page. Also works without a 
pageFooter: then a footer appears on the last page only.
summary
Printed once at the end. 
$F{...} shows the last data row, variables hold their final values. If the summary does not fit and moves to a page of its own, that page has no page header, column header or footer, and the 
lastPageFooter appears on the page before. With 
isSummaryWithPageHeaderAndFooter="true" on 
<jasperReport>, the summary page gets page header and footer (the 
lastPageFooter), but still no column header. This is JasperReports behaviour.
noData
Not supported.
Elements
Element
Supported
textField, 
staticText
Horizontal and vertical alignment, rotation, 
markup="html", line spacing (Single, 1_1_2, Double, Proportional), 
textAdjust (StretchHeight, ScaleFont, CutText), 
<box>, 
pattern / 
patternExpression, hyperlinks
rectangle
radius, 
mode, forecolor and backcolor, pen width, colour and style (Solid, Dashed, Dotted), fractional sizes such as 
height="0.8"
line
Pen as for rectangles. Lines thinner than 1 pt are drawn straight.
frame
Background, border, child elements positioned relative to the frame
image
Path or URL as an expression, Base64 data URIs (
data:image/png;base64,...), JPG and PNG. In VeloxFactory, images normally come from 
P_RESOURCE_ parameters.
Barcodes
QR Code, DataMatrix, PDF417, Code 128, Code 39, Code 93, EAN-8, EAN-13, Interleaved 2 of 5, Postnet. The code is an expression.
subreport
Data source from a list field (
$F{items}, also 
new JRBeanCollectionDataSource($F{items})), file name as an expression, 
.jasper is resolved to 
.jrxml
break
Page break, prints page footer, page header and column header
jr:table
Basic tables
Every element respects 
printWhenExpression, evaluated for each row.
Layout rules
StretchHeight makes the band taller, never the elements beside it. The next band starts below the lowest stretched field.
Vertical alignment with StretchHeight: if the text fits into the field, Top, Middle and Bottom apply as usual. Only overflowing text grows downwards from the top.
positionType="Float" moves an element down by the growth of the stretched fields above it. All other elements keep their position.
ScaleFont reduces the font size until the text fits into the box. Line breaks are allowed.
Page breaks fill the page down to the page footer. The decision uses the declared band height.
<box>: 
<pen> applies to all four sides, 
topPen, 
leftPen, 
bottomPen and 
rightPen override it. The colour falls back from the side pen to the box pen, then to 
forecolor, then to black. 
padding sets all four paddings, 
leftPadding etc. override it.
Defaults are the same as in JasperReports:
Rectangle: Opaque, white background, 1 pt black border.
Line: 1 pt. A pen width of 0 draws nothing.
Pen colour: 
lineColor takes precedence over 
forecolor.
Styles
Assignment: 
style="Name" on the 
reportElement. A style with 
isDefault="true" applies to all elements without a style of their own.
Inheritance: 
<style name="Child" style="Parent">.
Precedence: element attribute, then all matching conditional styles in order, then the style, then its parent.
Conditional styles are evaluated again for every row, for example to colour negative quantities red or to shade every second row.
Styles carry: 
mode, 
forecolor, 
backcolor, horizontal and vertical text alignment (
hTextAlign, 
vTextAlign and the older names), 
rotation, 
markup, font name, size, bold, italic, underline, strike-through, 
pattern, 
radius, image scaling and alignment, and the child elements 
<pen>, 
<box> and 
<paragraph>.
⚠️ An element with its own style does not inherit the default style. This is JasperReports behaviour. If a style should build on the default style, set 
style="Default" as its parent.
Expressions
Expressions are written in Java syntax, as in Jaspersoft Studio. They are evaluated by a built-in interpreter; no code is executed on the server. Expressions work in text fields, 
printWhenExpression, conditional styles, variables, 
patternExpression, hyperlinks, images, barcodes and subreport file names.
Syntax
References
$P{name}, 
$F{name}, 
$V{name}
Literals
"text" (with 
\" \\ \n \t \uXXXX), 
'text', 
42, 
1.5, 
10L, 
2.5d, 
true, 
false, 
null
Operators
? :, 
||, 
&&, 
==, 
!=, 
<, 
<=, 
>, 
>=, 
+, 
-, 
*, 
/, 
%, 
!, parentheses
Casts
(String), 
(Integer), 
(Long), 
(Double), 
(BigDecimal), 
(Number), 
(Boolean), 
(Date)
How values behave
+ concatenates as soon as one operand is text, from left to right: 
1 + 2 + "a" gives 
3a, 
"a" + 1 + 2 gives 
a12.
7 / 2 gives 
3 (integer division), 
7 / 2.0 gives 
3.5.
The type comes from the declared 
class of the field, parameter or variable. Declare amounts as 
java.math.BigDecimal, 
java.lang.Double or 
java.lang.Integer; a value declared as 
String is concatenated instead of added.
Three deliberate differences from Java make templates more robust:
null is concatenated as empty text (Java: 
"null").
== compares values like 
.equals().
Arithmetic with 
null returns 
null instead of failing.
Methods
All values
equals, 
toString, 
compareTo
Text
length, 
isEmpty, 
isBlank, 
trim, 
strip, 
toUpperCase, 
toLowerCase, 
substring, 
charAt, 
indexOf, 
lastIndexOf, 
contains, 
startsWith, 
endsWith, 
replace, 
replaceAll, 
replaceFirst, 
matches, 
concat, 
split, 
repeat, 
equalsIgnoreCase
Numbers
intValue, 
longValue, 
doubleValue, 
floatValue, 
setScale(n[, RoundingMode.X]), 
add, 
subtract, 
multiply, 
divide, 
negate, 
abs, 
signum, 
toPlainString
Dates
getTime, 
before, 
after
Lists
size, 
isEmpty, 
get(i), 
contains
Static calls, constants and constructors
Text: 
String.valueOf, 
String.format([Locale,] format, ...), 
String.join
Parsing: 
Integer.parseInt / 
valueOf, 
Long.parseLong, 
Double.parseDouble / 
valueOf, 
BigDecimal.valueOf, 
Boolean.valueOf / 
parseBoolean
Math: 
abs, 
round, 
floor, 
ceil, 
max, 
min, 
pow, 
sqrt
Constants: 
Boolean.TRUE / 
FALSE, 
BigDecimal.ZERO / 
ONE / 
TEN, 
RoundingMode.*, 
Locale.GERMANY, 
GERMAN, 
US, 
UK, 
ENGLISH, 
FRANCE, 
ITALY
Constructors: 
new java.util.Date(), 
new Date(ms), 
new java.text.SimpleDateFormat("...", [Locale]) with 
.format() and 
.parse(), 
new java.text.DecimalFormat("...").format(), 
new BigDecimal("1.5"), 
new Integer(...), 
new String(...), 
new Locale("de", "DE")
Examples
"Customer: " + $P{P_CUSTOMER}
$P{P_NOTE} == null || $P{P_NOTE}.isEmpty() ? "-" : $P{P_NOTE}
$F{status}.equals("late") && $F{qty} > 0
String.format("%s / %05d", $F{order}, $F{pos})
new java.text.SimpleDateFormat("EEEE, d. MMMM yyyy", java.util.Locale.GERMAN).format($F{date})
$F{amount}.setScale(2, java.math.RoundingMode.HALF_UP)
Legacy suffixes
Two JasperPHP shortcuts still work for existing templates: 
$F{amount}.toString() always returns two decimals in German format (
1.234,50), and 
$F{amount}.numberToText() spells out a number (Portuguese). For new templates, use 
pattern instead.
Not supported
$R{...} (resource bundles), arbitrary Java classes, lambdas and field access without a method call (
.length without parentheses). A text field with an unsupported expression falls back to plain placeholder substitution, which usually shows parts of the expression in the output. A condition with an unsupported expression counts as false, so the element is hidden.
Formatting numbers and dates
pattern / 
patternExpression: 
patternExpression takes precedence and is evaluated for each row, for example to switch the number of decimals per article.
Numbers use Java's DecimalFormat: 
#,##0.00, 
0.0%, 
000000, 
#,##0.00 €, 
#,##0.00;(#,##0.00), 
0.00E0. Rounding is HALF_EVEN as in Java; 
setScale rounds HALF_UP by default.
Dates use Java's SimpleDateFormat: 
dd.MM.yyyy, 
EEEE, d. MMMM yyyy, 
HH:mm.
Values that arrive as text are formatted as well when they contain a number or an ISO date (
2026-05-02, 
2026-05-02 14:30:00). This matters because render requests usually pass parameters as text.
Language and locale
Pass the parameter 
REPORT_LOCALE in the render request, for example 
de_DE. It controls decimal and thousands separators, month and day names, 
String.format and 
pattern. Built in are German (including 
de_CH), English, French, Spanish, Italian and Portuguese. Without 
REPORT_LOCALE, the default locale of the installation applies (English unless configured otherwise).
ℹ️ Do not declare 
REPORT_LOCALE as a parameter in the template. It is a built-in JasperReports parameter, and Jaspersoft Studio rejects a second declaration. Pass it in the render request or the schedule only.
Variables
Calculations: Sum, Count, Average, DistinctCount, Highest, Lowest, First, Nothing (current value). Count and Average only count values that are not null.
Reset: 
resetType="Report" or 
"Group". Groups reset correctly even without a group header band.
Expressions can be any supported expression, for example 
$F{qty} * $F{price}.
Built in: 
PAGE_NUMBER and 
REPORT_COUNT. For "Page N of M", use two text fields: 
"Page " + $V{PAGE_NUMBER}, and 
" of " + $V{PAGE_NUMBER} with 
evaluationTime="Report".
Upgrading templates from earlier versions
Templates built for earlier VeloxFactory versions keep working. Check them for these changes:
Conditions in PHP syntax (for example 
is_int(...), 
===, 
and or 
or in 
printWhenExpression) now count as false, and the element is hidden. Rewrite them in Java syntax.
Lines without 
<pen> are 1 pt wide instead of a hairline.
Element attributes override the style (previously the other way round).
Multi-page reports fit more rows per page and repeat the column header on every page.
Workarounds are no longer needed: concatenation with 
+, 
pattern, 
<box> and page footers on every page now work as in Jaspersoft Studio.
Known limits
Charts and crosstabs are not supported and render as an empty area. Use tiles, lists and aggregated groups instead.
noData band and 
$R{...} are not supported.
isBlankWhenNull="false" is ignored; null always prints as empty text.
A band that stretches shortly before the end of a page can reach into the page footer. Leave some space above the footer on pages with long texts.