Child Bands
===========

This example uses child bands. All band can have child bands attached. Child
band are bands that are attached to a parent band and will print below them::

    import os
    cur_dir = os.path.dirname(os.path.abspath(__file__))
    
    from django.contrib.auth.models import User
    
    from reportlab.lib.pagesizes import A4
    from reportlab.lib.units import cm
    from reportlab.lib.enums import TA_CENTER, TA_JUSTIFY
    from reportlab.lib.colors import navy, yellow, red
    
    from geraldo import Report, ReportBand, Label, ObjectValue, SystemField,\
        FIELD_ACTION_COUNT, FIELD_ACTION_AVG, FIELD_ACTION_MIN,\
        FIELD_ACTION_MAX, FIELD_ACTION_SUM, FIELD_ACTION_DISTINCT_COUNT, BAND_WIDTH,\
        RoundRect, Line
    
    class ChildBandsReport(Report):
        title = 'Child bands demonstration'
    
        class band_summary(ReportBand):
            height = 0.8*cm
            elements = [
                Label(text="Users count:", top=0.1*cm, left=0),
                ObjectValue(attribute_name='username', top=0.1*cm, left=4*cm,\
                    action=FIELD_ACTION_COUNT, display_format='%s permissions found'),
            ]
            child_bands = [
                ReportBand(
                    height = 0.6*cm,
                    elements = [
                        Label(text="Users ids average:", top=0.6*cm, left=0),
                        ObjectValue(attribute_name='id', top=0.6*cm, left=4*cm, action=FIELD_ACTION_AVG),
                    ]),
                ReportBand(
                    visible = False,
                    height = 0.6*cm,
                    elements = [
                        Label(text="Users ids minimum:", top=1.1*cm, left=0),
                        ObjectValue(attribute_name='id', top=1.1*cm, left=4*cm, action=FIELD_ACTION_MIN),
                    ]),
                ReportBand(
                    height = 0.6*cm,
                    elements = [
                        Label(text="Users ids maximum:", top=1.6*cm, left=0),
                        ObjectValue(attribute_name='id', top=1.6*cm, left=4*cm, action=FIELD_ACTION_MAX),
                    ],
                    borders = {'bottom': True}),
                ReportBand(
                    height = 0.6*cm,
                    elements = [
                        Label(text="Users ids sum:", top=2.1*cm, left=0),
                        ObjectValue(attribute_name='id', top=2.1*cm, left=4*cm, action=FIELD_ACTION_SUM),
                    ]),
                ReportBand(
                    visible = False,
                    height = 0.6*cm,
                    elements = [
                        Label(text="Users first name distinct:", top=2.6*cm, left=0),
                        ObjectValue(attribute_name='first_name', top=2.6*cm, left=4*cm, action=FIELD_ACTION_DISTINCT_COUNT),
                    ]),
            ]
            borders = {'all': True}
    
        class band_page_header(ReportBand):
            height = 1.3*cm
            elements = [
                SystemField(expression='%(report_title)s', top=0.1*cm, left=0, width=BAND_WIDTH,
                    style={'fontName': 'Helvetica-Bold', 'fontSize': 14, 'alignment': TA_CENTER}),
                Label(text="ID", top=0.8*cm, left=0),
                Label(text="Username", top=0.8*cm, left=3*cm),
                Label(text="First name", top=0.8*cm, left=8*cm),
                Label(text="Last name", top=0.8*cm, left=13*cm),
                Label(text="Staff", top=0.8*cm, left=18*cm),
            ]
            borders = {'bottom': Line(stroke_color=red, stroke_width=3)}
    
        class band_page_footer(ReportBand):
            height = 0.5*cm
            elements = [
                Label(text='Created with Geraldo Reports', top=0.1*cm),
            ]
            borders = {'top': Line(stroke_color=navy)}
    
        class band_detail(ReportBand):
            height = 0.7*cm
            elements = [
                ObjectValue(attribute_name='id', top=0, left=0),
                ObjectValue(attribute_name='username', top=0, left=3*cm),
                ObjectValue(attribute_name='first_name', top=0, left=8*cm),
                ObjectValue(attribute_name='last_name', top=0, left=13*cm),
                ObjectValue(attribute_name='is_staff', top=0, left=18*cm,
                    get_value=lambda instance: instance.is_staff and 'Yes' or 'No'),
            ]

Generating PDF...

    >>> report = ChildBandsReport(queryset=queryset)
    >>> from geraldo.generators import PDFGenerator
    >>> report.queryset = User.objects.order_by('id')
    >>> report.generate_by(PDFGenerator, filename=os.path.join(cur_dir, 'output/child-bands-report.pdf'))

The Result

- http://geraldo.svn.sourceforge.net/viewvc/geraldo/examples/child-bands-report.pdf

