Physical size,
A-series,
DPI & viewing.

{
  "module": "Compo 6.02",
  "name": "physical_size_a_series_dpi_and_viewing_context",
  "version": "1.1-corrective",
  "canonical_main_title": "Physical size, A-series, DPI, viewing context",
  "topic": "06_ФОРМАТ_ПОСТЕРА_И_СООТНОШЕНИЕ_СТОРОН",
  "scope": "PHYSICAL_CANVAS_SIZE_RASTER_DENSITY_PRINT_DPI_STANDARD_FORMAT_AND_VIEWING_GEOMETRY",
  "consumes": [
    "Compo6.00.CanvasDescriptor",
    "Compo6.00.rasterExtentPx?",
    "PhysicalSizeInput?",
    "RasterDensityInput?",
    "PrintDeviceDensityInput?",
    "ViewingContextInput?",
    "PhysicalFormatPolicy"
  ],
  "provides": [
    "PhysicalCanvasMetadata",
    "AseriesMatchResult",
    "RasterDensityResult",
    "PrintDeviceDensityDescriptor",
    "ViewingContextDescriptor",
    "MetricResult[canvas.physical.widthMm]",
    "MetricResult[canvas.physical.heightMm]",
    "MetricResult[canvas.physical.diagonalMm]",
    "MetricResult[canvas.physical.ppiX]",
    "MetricResult[canvas.physical.ppiY]",
    "MetricResult[canvas.physical.ppiMean]",
    "MetricResult[canvas.physical.angularWidthDeg]",
    "MetricResult[canvas.physical.angularHeightDeg]",
    "MetricResult[canvas.physical.angularDiagonalDeg]",
    "MetricResult[canvas.physical.pixelsPerDegreeX]",
    "MetricResult[canvas.physical.pixelsPerDegreeY]",
    "MetricResult[canvas.physical.confidence]",
    "physicalMetadataRef for CanvasDescriptor",
    "PhysicalFormatCorrectionRequest[]"
  ],
  "owns_metrics": [
    "canvas.physical.widthMm",
    "canvas.physical.heightMm",
    "canvas.physical.diagonalMm",
    "canvas.physical.ppiX",
    "canvas.physical.ppiY",
    "canvas.physical.ppiMean",
    "canvas.physical.angularWidthDeg",
    "canvas.physical.angularHeightDeg",
    "canvas.physical.angularDiagonalDeg",
    "canvas.physical.pixelsPerDegreeX",
    "canvas.physical.pixelsPerDegreeY",
    "canvas.physical.confidence"
  ],
  "descriptors_only": [
    "canvas.physical.sizeSource",
    "canvas.physical.aSeriesClass",
    "canvas.physical.aSeriesOrientation",
    "canvas.physical.ppiUniformityStatus",
    "canvas.physical.printDpi",
    "canvas.physical.viewingDistanceMm",
    "canvas.physical.viewingContextRef",
    "canvas.physical.status"
  ],
  "physical_size_input_schema": {
    "physicalWidthMm": "finite >0",
    "physicalHeightMm": "finite >0",
    "source": "EXPLICIT_DOCUMENT|DERIVED_FROM_RASTER_AND_PPI|STANDARD_FORMAT_BINDING|CUSTOM",
    "confidence": "0..1",
    "provenance": "object"
  },
  "raster_density_input_schema": {
    "mappingMode": "UNIFORM_PIXEL_DENSITY|INDEPENDENT_AXIS_DENSITY",
    "UNIFORM_PIXEL_DENSITY": "requires scalar ppi >0; optional ppiX/ppiY may be supplied only as consistency evidence and must both agree with scalar ppi within policy tolerance",
    "INDEPENDENT_AXIS_DENSITY": "requires ppiX>0 and ppiY>0; scalar ppi is forbidden because it would hide anisotropy",
    "provenance": "object",
    "rule": "density representation is explicit; no partial one-axis density"
  },
  "print_device_density_input_schema": {
    "dpi": "finite >0",
    "deviceRef": "optional output device/profile ref",
    "dotMappingRef": "optional explicit pixel-to-dot mapping",
    "provenance": "object",
    "important": "DPI describes output device dots per inch and is not interchangeable with raster PPI",
    "validation": "dpi must be finite >0 when supplied"
  },
  "viewing_context_input_schema": {
    "viewingContextRef": "string",
    "viewingDistanceMm": "finite >0",
    "viewerMode": "SINGLE_VIEWER|ESTIMATED_DISTANCE|CUSTOM",
    "confidence": "0..1",
    "provenance": "object",
    "no_default_distance": "missing distance means angular metrics N/A",
    "validation": "viewingContextRef + viewingDistanceMm + confidence are required when viewing context is supplied"
  },
  "physical_format_policy": {
    "aSeriesMatchMode": "EXACT_NOMINAL_MM|TOLERANT_MM",
    "aSeriesToleranceMm": "required finite >=0 only for TOLERANT_MM",
    "ppiUniformityRelativeTolerance": "finite >=0",
    "provenance": "STANDARD|STYLE_PRESET|EMPIRICAL|INITIAL_HEURISTIC"
  },
  "a_series_nominal_mm": {
    "standard": "ISO 216 nominal dimensions",
    "orientation_independent_match": true,
    "sizes": {
      "A0": [
        841,
        1189
      ],
      "A1": [
        594,
        841
      ],
      "A2": [
        420,
        594
      ],
      "A3": [
        297,
        420
      ],
      "A4": [
        210,
        297
      ],
      "A5": [
        148,
        210
      ],
      "A6": [
        105,
        148
      ],
      "A7": [
        74,
        105
      ],
      "A8": [
        52,
        74
      ],
      "A9": [
        37,
        52
      ],
      "A10": [
        26,
        37
      ]
    },
    "important": "nominal integer-mm table; no hidden fuzzy matching"
  },
  "a_series_semantics": {
    "EXACT_NOMINAL_MM": "unordered physical dimension pair must equal nominal integer-mm pair exactly",
    "TOLERANT_MM": "each unordered side may deviate by <= explicit aSeriesToleranceMm",
    "orientation": "PORTRAIT if physicalHeightMm>physicalWidthMm; LANDSCAPE if width>height; SQUARE is not an A-series nominal case",
    "no_physical_size": "aSeriesClass=N_A",
    "match_is_descriptor": "A4/A3/etc. is not a quality score",
    "ambiguous_tolerant_match": "if an explicit tolerance matches more than one nominal A-series class, result is AMBIGUOUS_MATCH and no class is guessed"
  },
  "raster_physical_mapping": {
    "derive_size_from_uniform_ppi": "widthMm = widthPx / ppi * 25.4; heightMm = heightPx / ppi * 25.4",
    "derive_axis_ppi_from_size": "ppiX = widthPx / (widthMm/25.4); ppiY = heightPx / (heightMm/25.4)",
    "uniformity_relative_error": "abs(ppiX-ppiY)/max(ppiX,ppiY)",
    "uniform_status": "UNIFORM|ANISOTROPIC|N_A",
    "ppiMean": "arithmetic mean of ppiX/ppiY only when both are valid; descriptor, not printer DPI",
    "conflict": "if explicit physical size + explicit uniform ppi + raster dimensions disagree beyond declared tolerance => INVALID/CONFLICT",
    "derive_size_from_independent_axis_ppi": "widthMm = widthPx/ppiX*25.4; heightMm = heightPx/ppiY*25.4",
    "independent_axis_conflict": "when physical size is also explicit, observed ppiX/ppiY must agree with declared independent axis densities within explicit policy tolerance",
    "mapping_mode_required": "density evidence without explicit mappingMode is INVALID rather than guessed"
  },
  "ppi_dpi_firewall": {
    "PPI": "pixels per inch; raster-to-physical sampling density",
    "DPI": "printer/output device dots per inch",
    "physical_size_inference": "PPI may infer size from raster pixels; DPI may not unless dotMappingRef explicitly defines pixel-to-dot mapping",
    "forbidden_alias": "canvas.physical.ppiMean != canvas.physical.printDpi",
    "quality_warning": "higher PPI or DPI is not automatically better without task/output context"
  },
  "viewing_geometry": {
    "angularWidthDeg": "2*atan(widthMm/(2*viewingDistanceMm))*180/pi",
    "angularHeightDeg": "2*atan(heightMm/(2*viewingDistanceMm))*180/pi",
    "angularDiagonalDeg": "2*atan(diagonalMm/(2*viewingDistanceMm))*180/pi",
    "pixelsPerDegreeX": "rasterWidthPx/angularWidthDeg when both exist",
    "pixelsPerDegreeY": "rasterHeightPx/angularHeightDeg when both exist",
    "distance_increase": "angular extents decrease monotonically as viewing distance increases",
    "common_physical_scale_with_distance": "scaling physical size and viewing distance by same factor preserves angular extent"
  },
  "ownership_map": {
    "6.00": "raw canvas geometry / aspect ratio / raster extent slot",
    "6.01": "square/portrait/landscape behavior",
    "6.02": "physical size / A-series / raster PPI / print DPI descriptor / viewing geometry",
    "6.03": "normalization and scale-invariance contract",
    "6.04": "adaptation hooks and tests"
  },
  "handoff_contracts": {
    "to_6.03": "physical metrics are context descriptors; 6.03 decides which normalized coordinate contracts are canonical",
    "to_6.04": "changes in physical size/PPI/viewing context become adaptation/recompute evidence",
    "to_typography_future": "pixels-per-degree/angular extent may be consumed later; 6.02 does not set font sizes",
    "to_topic7": "physical safe/bleed conversion may consume 6.02 physical size but safe/bleed ownership remains Topic7"
  },
  "metric_policy": {
    "physical_size": "descriptor only",
    "ppi": "descriptor only",
    "dpi": "device descriptor only",
    "angular_extent": "viewing-geometry descriptor only",
    "pixels_per_degree": "sampling/viewing descriptor only",
    "direct_scoring": "FORBIDDEN in 6.02",
    "higher_ppi_is_better": "FORBIDDEN",
    "higher_dpi_is_better": "FORBIDDEN",
    "larger_physical_size_is_better": "FORBIDDEN",
    "larger_angular_extent_is_better": "FORBIDDEN"
  },
  "hard_constraints": [
    "one metric = one owner",
    "6.02 must consume 6.00 raster extent/canvas identity and must not recompute canvas aspect geometry from content",
    "physicalWidthMm and physicalHeightMm must be positive finite when present",
    "no physical size may be invented from DPI alone",
    "PPI and DPI are distinct concepts and may never be aliased",
    "uniform scalar PPI may derive physical size only when raster pixel dimensions are known",
    "physical size + raster dimensions may derive ppiX/ppiY",
    "explicit uniform PPI conflicting with physical size/raster mapping beyond policy tolerance is invalid",
    "anisotropic ppiX/ppiY must be reported explicitly and not averaged into a fake uniform mapping",
    "A-series matching requires explicit physical dimensions and explicit match policy",
    "tolerant A-series matching requires explicit tolerance; no hidden mm tolerance",
    "A-series classification is orientation-insensitive with orientation reported separately",
    "viewing angular metrics require explicit viewingDistanceMm and physical size; no default viewing distance",
    "pixelsPerDegree requires both raster pixels and valid angular extent",
    "6.02 must not prescribe typography size, line length, margin, grid, safe area, object size, or layout",
    "physical size/viewing context do not replace 6.03 normalization contract",
    "stateful adaptation to physical/viewing changes remains 6.04",
    "safe/bleed ownership remains Topic7",
    "grid occupancy remains Topic8",
    "global balance/hierarchy/eye-flow remain future owners",
    "N/A != 0",
    "no beautyScore",
    "RasterDensityInput.mappingMode is mandatory when density evidence is supplied",
    "INDEPENDENT_AXIS_DENSITY requires both ppiX and ppiY and forbids scalar ppi aliasing",
    "TOLERANT_MM A-series matching that matches multiple nominal classes yields AMBIGUOUS_MATCH rather than selecting the first table entry",
    "print-device DPI must be positive finite when present",
    "viewing context must carry an explicit ref, positive distance and confidence when present"
  ],
  "initial_heuristics": {
    "reference_ppi_uniformity_relative_tolerance": {
      "value": 0.005,
      "provenance": "STYLE_PRESET",
      "note": "not a global default"
    },
    "numeric_epsilon": {
      "value": 1e-12,
      "provenance": "IMPLEMENTATION_HEURISTIC"
    }
  },
  "correction_policy": {
    "foreign_canvas_or_content_mutation": "FORBIDDEN",
    "missing_physical_size": "request explicit size or raster+PPI mapping",
    "ppi_physical_conflict": "request document/export pipeline owner correction",
    "dpi_ppi_confusion": "request explicit raster PPI or device dot-mapping; do not infer",
    "a_series_match_policy_missing": "request PhysicalFormatPolicy",
    "viewing_distance_missing": "request explicit ViewingContextInput",
    "normalization_issue": "route to Compo6.03",
    "adaptation_issue": "route to Compo6.04",
    "safe_bleed_issue": "route to Topic7"
  },
  "deferred_inputs": [
    "Compo6.03 normalization / scale-invariance contract",
    "Compo6.04 adaptation hooks / regression",
    "Topic7 physical safe/bleed conversion",
    "future typography/readability modules using angular metrics",
    "future global balance/hierarchy/eye-flow"
  ],
  "recompute_when": [
    "physical width/height changes",
    "raster extent changes",
    "PPI mapping changes",
    "print DPI/device profile changes",
    "A-series match policy changes",
    "viewing distance/context changes"
  ],
  "finality": "PHYSICAL_FORMAT_DENSITY_AND_VIEWING_CONTEXT_ONLY"
}