如何在XSL-FO（FOP 2.1）中将图形/表格与页面的顶部或底部对齐

Question

In the case figure or table is a bit larger it would be really suitable to move them to the top or the bottom of the page. The ability to reflow table to the next page with repeating its headers is great but not always what I want. In the case table or figure fits well in the page and it is not necessarily anchored to a paragraph, there is no reason to reflow it. It would be better to make it “floating” outside the body of the page.

This answer is really inspiring but I am not sure how to apply it to my case. I would be happy if I could do it according to a @rendition attribute of the table.

<fo:layout-master-set>
    <fo:simple-page-master master-name="PageMaster.Title-Page" page-height="{$paper-height}" page-width="{$paper-width}" margin-left="{$margin-left}" margin-right="{$margin-right}" margin-top="{$margin-top}" margin-bottom="{$margin-bottom}">
        <fo:region-body/>
    </fo:simple-page-master>
    <fo:simple-page-master master-name="PageMaster.CopyRight-Page" page-height="{$paper-height}" page-width="{$paper-width}" margin-left="{$margin-left}" margin-right="{$margin-right}" margin-top="{$margin-top}" margin-bottom="{$margin-bottom}">
        <fo:region-body display-align="after"/>
    </fo:simple-page-master>
    <fo:simple-page-master master-name="PageMaster.TOC" page-height="{$paper-height}" page-width="{$paper-width}" margin-left="{$margin-left}" margin-right="{$margin-right}" margin-top="18mm" margin-bottom="{$margin-bottom}">
        <fo:region-body margin="0mm 0mm 0mm 60mm"/>
    </fo:simple-page-master><!-- Whole page left and right masters -->
    <fo:simple-page-master master-name="PageMaster.Page-Right.First" page-height="{$paper-height}" page-width="{$paper-width}" margin-left="{$margin-left}" margin-right="{$margin-right}" margin-top="{$margin-top}" margin-bottom="{$margin-bottom}">
        <fo:region-body margin="8mm 0mm 20mm 0mm" column-count="2" column-gap="5mm"/>
        <fo:region-before region-name="Region-Before-Right" extent="10mm" display-align="after"/>
        <fo:region-after region-name="Region-After-First" extent="20mm" display-align="before"/>
    </fo:simple-page-master>
    <fo:simple-page-master master-name="PageMaster.Page-Left" page-height="{$paper-height}" page-width="{$paper-width}" margin-left="{$margin-left}" margin-right="{$margin-right}" margin-top="{$margin-top}" margin-bottom="{$margin-bottom}">
        <fo:region-body margin="8mm 0mm 20mm 0mm" column-count="2" column-gap="5mm"/>
        <fo:region-before region-name="Region-Before-Left" extent="10mm" display-align="after"/>
    </fo:simple-page-master>
    <fo:simple-page-master master-name="PageMaster.Page-Right" page-height="{$paper-height}" page-width="{$paper-width}" margin-left="{$margin-left}" margin-right="{$margin-right}" margin-top="{$margin-top}" margin-bottom="{$margin-bottom}">
        <fo:region-body margin="8mm 0mm 20mm 0mm" column-count="2" column-gap="5mm"/>
        <fo:region-before region-name="Region-Before-Right" extent="10mm" display-align="after"/>
    </fo:simple-page-master>
    <fo:simple-page-master master-name="PageMaster.Blank" page-height="{$paper-height}" page-width="{$paper-width}" margin-left="{$margin-left}" margin-right="{$margin-right}" margin-top="{$margin-top}" margin-bottom="{$margin-bottom}">
        <fo:region-body margin="8mm 0mm 20mm 0mm" column-count="2" column-gap="5mm"/>
    </fo:simple-page-master><!-- Sequence of even / odd pages -->
    <fo:page-sequence-master master-name="Content-Pages">
        <fo:repeatable-page-master-alternatives>
            <fo:conditional-page-master-reference master-reference="PageMaster.Blank" blank-or-not-blank="blank"/>
            <fo:conditional-page-master-reference master-reference="PageMaster.Page-Right.First" odd-or-even="odd" page-position="first"/>
            <fo:conditional-page-master-reference master-reference="PageMaster.Page-Left" odd-or-even="even"/>
            <fo:conditional-page-master-reference master-reference="PageMaster.Page-Right" odd-or-even="odd"/>
        </fo:repeatable-page-master-alternatives>
    </fo:page-sequence-master>
</fo:layout-master-set>

Answer 1

As Tony Graham commented, FOP does not support before floats yet (strangely enough, it silently swallows them without a warning).

However, you could use footnotes instead to place your tables at the bottom of the pages in which they are referenced. If I remember correctly, FOP favours placing the footnotes in their entirety over adding more "flowing" content, so the result should be the expected one.

FO example:

<?xml version="1.0" encoding="UTF-8"?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
    <fo:layout-master-set>
        <fo:simple-page-master master-name="simple" page-width="14.85cm" page-height="21cm">
            <fo:region-body margin="1in"/>
        </fo:simple-page-master>
    </fo:layout-master-set>

    <fo:page-sequence master-reference="simple">
        <fo:flow flow-name="xsl-region-body" text-align="justify">
            <fo:block>Maecenas lectus nisl, pulvinar at tincidunt a, semper sit amet nibh. Morbi at dolor quis sem porta volutpat. Quisque eget magna lectus. Donec laoreet congue enim ut ullamcorper. Ut vestibulum consequat neque rhoncus laoreet.</fo:block>
            <fo:block>Here is a block referring to a <fo:footnote><fo:inline font-weight="bold">TABLE 1</fo:inline><fo:footnote-body>
                <fo:block font-weight="bold">TABLE 1:</fo:block>
                <fo:table width="100%" table-layout="fixed">
                    <fo:table-column column-width="30%"/>
                    <fo:table-column column-width="70%"/>
                    <fo:table-body>
                        <fo:table-row>
                            <fo:table-cell><fo:block>A</fo:block></fo:table-cell>
                            <fo:table-cell><fo:block>132</fo:block></fo:table-cell>
                        </fo:table-row>
                        <fo:table-row>
                            <fo:table-cell><fo:block>B</fo:block></fo:table-cell>
                            <fo:table-cell><fo:block>556638</fo:block></fo:table-cell>
                        </fo:table-row>
                        <fo:table-row>
                            <fo:table-cell><fo:block>C</fo:block></fo:table-cell>
                            <fo:table-cell><fo:block>574</fo:block></fo:table-cell>
                        </fo:table-row>
                        <fo:table-row>
                            <fo:table-cell><fo:block>D</fo:block></fo:table-cell>
                            <fo:table-cell><fo:block>8893</fo:block></fo:table-cell>
                        </fo:table-row>
                    </fo:table-body>
                </fo:table>
            </fo:footnote-body></fo:footnote>; the table should be in the same page as the bolded part.</fo:block>
            <fo:block>This is another block of content. Lorem ipsum dolor sit amet, consectetur adipiscing elit. In tincidunt ipsum eget nisl iaculis fringilla. Pellentesque sagittis quam tellus, ac varius nisl rutrum non. Phasellus eget imperdiet velit.</fo:block>
            <fo:block>Aenean eleifend, arcu et feugiat facilisis, diam orci luctus lectus, id laoreet ex risus sed nunc. Proin eget scelerisque orci. Donec porttitor tellus libero, a molestie orci vestibulum mattis. Ut eu massa ac massa sagittis molestie. Quisque viverra ipsum vel mauris laoreet aliquet.</fo:block>
            <fo:block>Maecenas lectus nisl, pulvinar at tincidunt a, semper sit amet nibh. Morbi at dolor quis sem porta volutpat. Quisque eget magna lectus. Donec laoreet congue enim ut ullamcorper. Ut vestibulum consequat neque rhoncus laoreet.</fo:block>
            <fo:block> Sed ipsum massa, maximus eget posuere et, pellentesque accumsan nulla. Vestibulum erat mauris, imperdiet at mattis in, rhoncus eget orci. Nullam rhoncus hendrerit magna. </fo:block>  
        </fo:flow>
    </fo:page-sequence>
</fo:root>

Resulting output:

The downside of using footnotes is that the constraint on footnote placement is more strict than the one on before floats (which can be placed in a page following their anchor-area, as per section 6.12.2 of the recommentation ), so there could be layout problems (empty areas in the pages) if the input has many tables cited in a sequence of paragraphs.

(disclosure: I am a FOP developer, though not very active nowadays)