LeftAlignmentHandler spread each line's residual space across its word gaps,
clamped to max_spacing. A line whose residual divided to under max_spacing was
stretched flush, one that exceeded it was not, so left-aligned text was
justified sometimes, by a different amount per line - which reads as a wobbling
right edge rather than as ragged-right. Centre/right did the same, and computed
their start position from a different spacing than the one they returned, so
centred lines were not centred.
Ragged alignments now use a constant word space - the font's own space advance,
clamped to the style's bounds - and report overflow instead of tightening, so
line breaking decides what fits rather than rendering squeezing it.
Justification kept two further defects:
- the final line of a paragraph was stretched across the measure, so a
three-word tail was spread edge to edge. Line now carries is_paragraph_end,
set on the line holding the last word, and renders flush left. A paragraph
continued on the next page is not marked, so it stays justified.
- gaps were floored per gap with a truncated remainder, discarding the
fractional part of both. Lines stopped one or two pixels short, differently
each time. Distributing by cumulative rounding makes the gaps sum to the
residual exactly; advance ends now land identically on every line.
Alignment is configurable rather than hardcoded: PageStyle.default_alignment,
defaulting to JUSTIFY for body text. text_align on abstract and concrete styles
defaults to None meaning "unspecified", so HTML without text-align inherits the
page default while explicit CSS still wins. Headings are never justified.
paragraph_layouter placed lines at page.border_size while sizing them to
available_width, which subtracts both paddings. Text therefore started flush
against the left border and the entire padding budget accumulated on the right,
so lines broke well short of the right border.
Page now describes its content box directly - content_origin, content_rect and
remaining_height - and the layouters use it instead of each recomputing the
geometry from border_size. The four block layouters had all been computing
remaining space as size[1] - y_offset - border_size, subtracting the border but
not the bottom padding, so every block type could be placed into the bottom
padding; remaining_height fixes that too.
Page also gains an origin, defaulting to (0, 0). That is inert for a top-level
page but lets a page be positioned inside another surface, which table cells
need in order to be laid out by the normal engine.
Golden images regenerated: content now sits inside the padding on all sides.
Twelve specs covering the defects found auditing the block/table rendering
path, plus the pagination dead-end and the broken background renderer.
Each spec carries a reproduction of the defect against 2a543d0, a design with
concrete signatures, and acceptance criteria. Five design invariants are stated
up front so future changes can be rejected by reference rather than re-argued.
dtourolle