Class: Fontisan::Stitcher::PartitionStrategy::ByPlane

Inherits:
Base
  • Object
show all
Defined in:
lib/fontisan/stitcher/partition_strategy/by_plane.rb

Overview

Partition codepoints by Unicode plane (BMP, SMP, SIP, …).

For each plane with codepoints:

- if the count fits under +cap+, emit one partition named
+:plane_<n>+ (e.g. +:plane_0+, +:plane_2+);
- otherwise sub-split along the recognized sub-plane block
boundaries (+RECOGNIZED_BLOCKS+), naming partitions
+:plane_<n>_a+, +:plane_<n>_b+, and so on.

If a single ATOMIC_BLOCKS entry alone exceeds cap, raises PartitionCapExceededError — the partitioner cannot satisfy the cap and the caller must use a smaller cap, split manually, or switch to a format with a higher glyph limit. CARVE_OUT_BLOCKS entries are chunkable and will be sliced like :other if they exceed cap.

Constant Summary collapse

ATOMIC_BLOCKS =

Atomic sub-plane blocks: cannot be sub-split further because no finer-grained Unicode boundary exists inside them. If one alone exceeds cap, raise PartitionCapExceededError.

Labels follow the Unicode Blocks.txt block names with spaces replaced by underscores.

{
  "CJK_Ext_B" => 0x2A700..0x2B73F,
  "CJK_Ext_C" => 0x2B740..0x2B81F,
  "CJK_Ext_D" => 0x2B820..0x2CEAF,
  "CJK_Ext_E" => 0x2CEB0..0x2EBEF,
  "CJK_Ext_F" => 0x2EBF0..0x2EE5F,
}.freeze
CARVE_OUT_BLOCKS =

Carve-out boundaries: sub-plane regions large enough to warrant their own partition bucket when a plane overflows cap. Unlike atomic blocks, these are chunkable — if one alone exceeds cap, it gets sliced into +cap+-sized chunks like :other does, never raised.

{
  "CJK_Unified_Ideographs" => 0x4E00..0x9FFF,
  "Hangul_Syllables" => 0xAC00..0xD7AF,
}.freeze
RECOGNIZED_BLOCKS =

Every codepoint range recognized as a distinct sub-plane bucket. Atomic blocks first, then carve-out blocks. Used by the bucketing pass to decide what gets its own partition vs. falls into :other.

ATOMIC_BLOCKS.merge(CARVE_OUT_BLOCKS).freeze

Constants inherited from Base

Fontisan::Stitcher::PartitionStrategy::Base::COMPOSITE_HEADROOM, Fontisan::Stitcher::PartitionStrategy::Base::DEFAULT_CAP, Fontisan::Stitcher::PartitionStrategy::Base::NOTDEF_RESERVED

Instance Method Summary collapse

Methods inherited from Base

cap_for

Instance Method Details

#call(cp_map, cap: DEFAULT_CAP) ⇒ Blueprint

Parameters:

  • cp_map (Hash{Integer=>Object}) —

    codepoint → donor label

  • cap (Integer) (defaults to: DEFAULT_CAP) —

    max codepoints per partition

Returns:



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# File 'lib/fontisan/stitcher/partition_strategy/by_plane.rb', line 55

def call(cp_map, cap: DEFAULT_CAP)
  grouped = group_by_plane(cp_map)
  partitions = grouped.flat_map do |plane_num, entries|
    build_partitions_for_plane(plane_num, entries, cap)
  end
  Blueprint.new(partitions: partitions)
end