anchor.diff:  
   == TODO
   
  -* don't crash if theme data is empty
  -* don't crash if cover image does not exist; fail gracefully with warning
  -* file issue in prawn-svg not to move cursor (maybe an option?)
  +.1.5.0.alpha.13
  +* ensure book chapters and parts start on recto page when @ppbook (using start_new_chapter / start_new_page methods?)
  +  - need a way to add excludes
  +* should we use the term "column" instead of "placement" in running content
  +
  +//--
  +* generate fonts without PS Glyph Names to reduce file size (waiting PR #550 to be marged)
  +  - create script that can generate fonts entirely from original font source
  +* FIXME if a page is left empty, writing running content on it causes ghostscript to report an error
  +  - problem is no color space is set; can call update_colors to fix
  +  - maybe have a skip_page helper?
  +  - doesn't yet apply since we don't yet insert blank pages in content
  +* SIMPLE: document vw/vh measurement units in theming guide (make it clear it only applies in certain cases)
  +* SIMPLE: in theming guide, emphasize not using the fallback font when working with very large documents; explain that default theme uses a fallback font
  +* rework resolve_image_path API so it's more logical; override based on type of first argument; document as option
  +* document how to test / use a PR
  +  - see https://github.com/asciidoctor/asciidoctor-pdf/issues/462#issuecomment-246200953
  +* FILE ISSUE break printed URIs at each forward slash (and perhaps at ? and & too)
  +* add empty? method to Page (instead of page_empty? on document)
  +* SIMPLE: add warning that AsciiDoc table cell content is not supported; print as raw source
  +* implicit width of inline image calculated incorrectly (see sandbox/issue-494)
  +* FILE ISSUE in prawn-svg not to move cursor (maybe an option?)
   * FILE ISSUE: prevent import_page from adding an extra page; leaves blank page when placing two inserts in a row
     - have import_page first delete current page if page is empty
   * autowidth causes cells in header row to break word (wraps by char to fit; does not expand table)
   * dry_run should start at cursor of main document (or as option); total height calculation would need to be revised
     - this should fix height calculation when content is split over a page break (leaving small amount of excess)
  -* FILE ISSUE: if the image type cannot be resolved from file extension (e.g., when target is a URL), honor format attribute like core
  -* SIMPLE: add warning that AsciiDoc table cell content is not supported; print as raw source
  +* allow height of inline image to be set to line height (perhaps 1em?)
  +* add support for format attribute on image macro to image-related attributes such as title-page-background-image
  +  - support explicit image format for cover page image and page background image
  +* need some sort of post_construct method for converter that receives document
  +  - monkeypatch?
  +* backport resize method from prawn-svg and use it in converter
  +* create document that explains how built-in fonts are generated and what subsets are selected
  +  - I need instructions for myself so I know how to update/modify the fonts
  +  - document in theming guide what must be done to prepare fonts (old-style 'kern' table, optionally subset) (file issue!)
  +* consider supporting icon tag in parser to simplify how inline icons are stored; simpler use of passthrough content
   * cache stateless cell data resolved from theme (don't need to recalc each time; at least per table)
  -* autowidth on table doesn't work for multi-line content (width based on normalized value)
  +* autowidth on table doesn't work for multi-line content (prawn-table bases width calculation on normalized value)
   * table logic: does the layout_table_caption have to be inside the table block? can we pre-calculate the actual width for the caption? does the table offer a callback we can use to keep the caption on the same page as the table?
  -* FILE ISSUE: enable/implement key table_font_style
  -* SIMPLE: in theming guide, emphasize not using the fallback font when working with very large documents; explain that default theme uses a fallback font
   * introduce object to store/organize running content data and specs
   * QUESTION: should we set pdf-anchor attribute on every node that has an id?
  +  - isn't it required for cross references to work?
   * QUESTION: should theme font handle hierarchical keys (either explicitly or implicitly)
   * need to support .canvas role on image so it isn't shrunk to fit inside top/bottom margins
     - perhaps .canvas, .canvas-x, .canvas-y
   * SIMPLE: missing text_transform in some places in theming guide
   * FILE ISSUE: when split source listing, add top padding to bounding box (or is it the line metrics top?)
     - perhaps this has to do with the a miscalculation in dry run when not starting from same y position?
  -* prawn-gmagick (fixes PNG transparency issue, adds gif support); don't fail-fast on gif if gem is detected
  +* test prawn-gmagick (fixes PNG transparency issue, adds gif support); don't fail-fast on gif if gem is detected
     - https://github.com/packetmonkey/prawn-gmagick
  -* stroke and fill multi-page sidebar block (#259) and example block (#362)
  +* stroke and fill multi-page sidebar block (#259), quote/verse block (#270), and example block (#362)
   * support URL images in running content
  -* support explicit image format for cover page image and page background image
   * support pdfwidth for inline image
   * SIMPLE: add defaults for table_header_cell in theming guide, including when a key inherits by default
   * rewrite optimize-pdf using rghost (#535) (also see #21 and #22)
     - add Optimizer class; wire to cli (separate issue?)
  -* add feature to number bullets according to section number (needed for OpenDevise agreement)
  -* should we use the term "column" instead of "placement" in running content
  +* add feature to number bullets according to section number (needed for OpenDevise agreements)
   * outline should link to title page if there's a cover page (skip cover page and ensuing blank page)
  -* document how to test / use a PR
  -* SIMPLE: document vw/vh measurement units in theming guide (make it clear it only applies in certain cases)
   * might be better to organize fragments of source chunks by lines (and pass that around) to simplify post-processing
   * support negative start value for list (#498)
     - need to count negative numbers in correct direction
  
positive.code: * allow dynamic background image with page number in path
  * running header/footer covers content (perhaps just a limitation that needs to be documented)
  * document that palette-based transparent in PNGs is not supported
  * create document that explains how built-in fonts are generated and what subsets are selected
    - document in theming guide what must be done to prepare fonts (old-style 'kern' table, optionally subset) (file issue!)
  * add broader character range to monospace font so we can drop fallback font by default (#282)
    - consider having a fallback for prose and fallback for literal
  * file issue for prawn to preserve space (even w/ guards, spaces don't preserve over wrapped lines)
  
negative.code: * check that color of table edges set to table_grid_color??
  * shouldn't the default align for headings be $base_align??
  * should not wrap at formatting mark unless it is at a break opportunity
    - the problem here is that Prawn is allowing breaks at the boundaries of text fragments; it should only look at the contents
    - FILE ISSUE in Prawn!
  * be more consistent with how examples are shown in theming-guide.adoc (do we show last segment only?)
  * allow top as alternative to margin_top for all elements on title page (#431)
  * swallowing exceptions! (any use of e.message in a string is dangerous)
  