fdl_constants.h File Reference

Named constants replacing magic numbers throughout the FDL core library. More...

#include <cstddef>
#include <cstdint>

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Variables
constexpr double	fdl::constants::kCenterDivisor = 2.0
	Divisor for centering content (span / 2 = center offset).
constexpr int	fdl::constants::kDefaultJsonIndent = 2
	Default JSON serialization indent (spaces per level).
constexpr char	fdl::constants::kCustomAttrPrefix = '_'
	Custom attribute key prefix character.
Alignment factors
Used by template application to position content within canvases. 0.0 = left/top, 0.5 = center, 1.0 = right/bottom.
constexpr double	fdl::constants::kAlignStart = 0.0
	Left or top alignment factor.
constexpr double	fdl::constants::kAlignCenter = 0.5
	Center alignment factor.
constexpr double	fdl::constants::kAlignEnd = 1.0
	Right or bottom alignment factor.
Identity / default values
constexpr double	fdl::constants::kIdentitySqueeze = 1.0
	No anamorphic distortion (1:1 squeeze).
Banker's rounding constants
Used by fdl_round() for half-to-even rounding per the FDL spec.
constexpr double	fdl::constants::kHalfway = 0.5
	Halfway value for rounding decisions.
constexpr double	fdl::constants::kFpHalfwayTolerance = 1e-15
	FP tolerance for detecting exact halfway values.
constexpr int	fdl::constants::kEvenDivisor = 2
	Divisor for even/odd detection (v % 2).
constexpr int64_t	fdl::constants::kPositiveSign = 1
	Positive sign multiplier.
constexpr int64_t	fdl::constants::kNegativeSign = -1
	Negative sign multiplier.
constexpr int64_t	fdl::constants::kEvenRoundingAdjustment = 1
	Step for adjusting even-rounding results (v +/- 1).
Protection factor
Protection dimensions = framing_dims * (kProtectionBase - protection_fraction).
constexpr double	fdl::constants::kProtectionBase = 1.0
	Base factor for protection calculation (100%).
Bit-packing shifts for handle deduplication keys
constexpr unsigned	fdl::constants::kPackKey2Shift = 32
	Shift for packing two 32-bit indices into a 64-bit key.
constexpr unsigned	fdl::constants::kPackKey3HighShift = 40
	High-index shift in three-value pack (bits [40..59]).
constexpr unsigned	fdl::constants::kPackKey3MidShift = 20
	Mid-index shift in three-value pack (bits [20..39]).
FDL spec version defaults
constexpr int	fdl::constants::kDefaultVersionMajor = 2
	Default FDL specification version major.
constexpr int	fdl::constants::kDefaultVersionMinor = 0
	Default FDL specification version minor.
Buffer sizes
constexpr size_t	fdl::constants::kErrorBufferSize = 256
	Size of snprintf error message buffers.
Geometry path return codes
Used by geometry_get_dims_anchor_from_path and fdl_resolve_geometry_layer.
constexpr int	fdl::constants::kGeometryNotFound = 1
	Requested geometry layer is not present.
constexpr int	fdl::constants::kGeometryInvalidPath = -1
	Invalid geometry path enum value.
Hash combination
constexpr size_t	fdl::constants::kHashCombineShift = 1
	Bit shift for XOR-based hash combination.
Default framing intent aspect ratio (1:1)
constexpr int64_t	fdl::constants::kDefaultAspectRatio = 1
	1:1 aspect ratio for generated framing intents.
Custom attribute return codes and type values
constexpr int	fdl::constants::kCustomAttrSuccess = 0
	Operation succeeded.
constexpr int	fdl::constants::kCustomAttrError = -1
	Operation failed (type mismatch, not found, etc.).
constexpr uint32_t	fdl::constants::kCustomAttrTypeNone = 0
	Attribute not found.
constexpr uint32_t	fdl::constants::kCustomAttrTypeString = 1
	String attribute.
constexpr uint32_t	fdl::constants::kCustomAttrTypeInt = 2
	Integer attribute.
constexpr uint32_t	fdl::constants::kCustomAttrTypeFloat = 3
	Floating-point attribute.
constexpr uint32_t	fdl::constants::kCustomAttrTypeBool = 4
	Boolean attribute.
constexpr uint32_t	fdl::constants::kCustomAttrTypePointF64 = 5
	Point (x, y) attribute.
constexpr uint32_t	fdl::constants::kCustomAttrTypeDimsF64 = 6
	Dimensions (width, height) float attribute.
constexpr uint32_t	fdl::constants::kCustomAttrTypeDimsI64 = 7
	Dimensions (width, height) integer attribute.
constexpr uint32_t	fdl::constants::kCustomAttrTypeOther = 8
	Unsupported JSON type.
Floating-point comparison tolerances
Match Python math.isclose() defaults used for FDL value comparisons.
constexpr double	fdl::constants::kRelTol = 1e-9
	Relative tolerance for fp comparison.
constexpr double	fdl::constants::kAbsTol = 1e-6
	Absolute tolerance for fp comparison.
Thread-local cache limits
constexpr size_t	fdl::constants::kTlCacheMaxEntries = 256
	Max entries before a thread-local string cache auto-clears.
First-class custom attribute name constants
Well-known attribute names set by template application.
constexpr const char *	fdl::constants::kAttrScaleFactor = "scale_factor"
	Template scale factor (float).
constexpr const char *	fdl::constants::kAttrContentTranslation = "content_translation"
	Template content translation (point_f64).
constexpr const char *	fdl::constants::kAttrScaledBoundingBox = "scaled_bounding_box"
	Template scaled bounding box (dims_f64).

Detailed Description

Named constants replacing magic numbers throughout the FDL core library.

Every numeric literal in the codebase (except 0 and 0.0) must be a named constant defined here or in the public header (fdl_core.h). This ensures readability-magic-numbers and cppcoreguidelines-avoid-magic-numbers pass with no whitelist.