donner Namespace Reference

Top-level Donner namespace, which is split into different sub-namespaces such as donner::svg and donner::css. More...

Namespaces
namespace	css
	Donner CSS library, a standalone composable CSS parser.
namespace	parser
	Parsers for shared data types such as NumberParser and LengthParser.
namespace	svg
	Donner SVG library, which can load, manipulate and render SVG files.
namespace	xml
	XML parsing and document model support, top-level objects are donner::xml::XMLParser and donner::xml::XMLDocument.

Classes
struct	AbsoluteLengthMetrics
	A container with ratios for converting absolute lengths, such as "cm" or "in", see https://www.w3.org/TR/css-values/#absolute-lengths. More...
struct	Box
	A 2D axis-aligned bounding box. More...
struct	CaseInsensitiveCharTraits
	Type traits for case-insensitive string comparison, usable with algorithms that accept an STL std::char_traits. More...
class	ElementTraversalGenerator
	Selectors may need to traverse the tree in different ways to match, and this is abstracted away using C++20 coroutines. More...
class	FakeElement
	A test fake for a type that satisfies the ElementLike concept. More...
struct	FileOffset
	Error context for a failed parse, such as the error reason, line, and character offset. More...
struct	FileOffsetRange
	Holds a selection range for a region in the source text. More...
struct	FontMetrics
	A container for font information relevant for computing font-relative lengths, per https://www.w3.org/TR/css-values/#font-relative-lengths. More...
struct	Length
	Parses a CSS <length-percentage> type as defined by https://www.w3.org/TR/css-values-3/#typedef-length-percentage. More...
struct	MathConstants
	Contains a set of math constants for the specified type (float or double). More...
struct	MathConstants< double >
	Math constants for double. More...
struct	MathConstants< float >
	Math constants for float. More...
class	OptionalRef
	A class that simulates an optional reference to a constant object of type T. More...
struct	ParseError
	Error context for a failed parse, such as the error reason, line, and character offset. More...
class	ParseResult
	A parser result, which may contain a result of type T, or an error, or both. More...
struct	QuadraticSolution
	Holds the solution of a quadratic equation, as returned by SolveQuadratic. More...
class	RcString
	A reference counted string, that is copy-on-write and implements the small-string optimization. More...
class	RcStringOrRef
	An in-transit type that can hold either an RcString or std::string_view, to enable transferring the RcString reference or also accepting a non-owning std::string_view from API surfaces. More...
class	Runfiles
	Helper class to access bazel runfiles in a test environment. More...
class	SmallVector
	A vector with small-size optimization. More...
class	StringUtils
	A collection of string utils, such as case-insensitive comparison and StartsWith/EndsWith. More...
struct	Transform
	A 2D matrix representing an affine transformation. More...
class	Utf8
	Utility class for working with UTF-8 encoded strings. More...
struct	Vector2
	A 2D vector, (x, y). More...

Concepts
concept	ElementLike
	Concept for types that can be matched against a selector, such as a donner::svg::SVGElement.
concept	StringLike
	A concept for types that are string-like, i.e.

Typedefs
using	Boxd = Box<double>
	Shorthand for Box<double>.
using	Entity = entt::entity
	Entity type for the Registry, a std::uint32_t alias.
using	Registry = entt::basic_registry<Entity, std::allocator<Entity>>
	Registry type for the SVG ECS, which is the entry point for storing all data.
using	EntityHandle = entt::basic_handle<Registry>
	Convenience handle for a Entity with an attached Registry.
using	Lengthd = Length<double>
	Shorthand for Length<double>.
Typedefs
using	Transformf = Transform<float>
	Shorthand for Transform<float>
using	Transformd = Transform<double>
	Shorthand for Transform<double>
using	Vector2f = Vector2<float>
	Shorthand for Vector2<float>
using	Vector2d = Vector2<double>
	Shorthand for Vector2<double>
using	Vector2i = Vector2<int>
	Shorthand for Vector2<int>

Enumerations
enum class	LengthUnit {   None ,   Percent ,   Cm ,   Mm ,   Q ,   In ,   Pc ,   Pt ,   Px ,   Em ,   Ex ,   Ch ,   Rem ,   Vw ,   Vh ,   Vmin ,   Vmax }
	The unit identifier for a length, corresponding to CSS unit identifiers. More...
enum class	StringComparison : uint8_t {   Default ,   IgnoreCase }
	String comparison options, e.g. case sensitivity. More...

Functions
auto	operator<=> (Entity lhs, Entity rhs)
	Compare two Entity values.
template<ElementLike T>
ElementTraversalGenerator< T >	singleElementGenerator (T element)
	A generator that yields a single element, if it exists.
template<ElementLike T>
ElementTraversalGenerator< T >	parentsGenerator (T element)
	A generator that yields all parents of an element, repeatedly following parentElement() until reaching the root.
template<ElementLike T>
ElementTraversalGenerator< T >	previousSiblingsGenerator (T element)
	A generator that yields all siblings of an element, in reverse order.
template<ElementLike T>
ElementTraversalGenerator< T >	allChildrenRecursiveGenerator (T element)
	A generator that yields all children of an element recursively with pre-order traversal.
std::ostream &	operator<< (std::ostream &os, LengthUnit unit)
	OStream output operator, writes the enum value as a stream, e.g. Percent or Px.
float	NarrowToFloat (double from)
	Semantically represent a narrowing conversion, such as converting a double to a float, to make the conversion more visible.
template<typename T >
const T &	Min (const T &a, const T &b)
	Returns minimum of the provided values.
template<typename T , typename... Args>
const T &	Min (const T &a, const T &b, Args &&... args)
	Returns minimum of the provided values.
template<typename T >
const T &	Max (const T &a, const T &b)
	Returns maximum of the provided values.
template<typename T , typename... Args>
const T &	Max (const T &a, const T &b, Args &&... args)
	Returns maximum of the provided values.
float	Abs (float a)
	Returns the absolute value of the number.
double	Abs (double a)
	Returns the absolute value of the number.
template<typename T , typename = std::enable_if<std::is_integral<T>::value && std::is_signed<T>::value>>
T	Abs (T a)
	Returns the absolute value of the number.
template<typename T , typename = std::enable_if<std::is_floating_point<T>::value>>
T	Round (T orig)
	Round a floating point value to an integer.
template<typename T >
T	Lerp (T a, T b, const float t)
	Returns linear interpolation of a and b with ratio t.
template<typename T >
const T	Clamp (T value, T low, T high)
	Clamps a value between low and high.
template<typename T >
bool	NearEquals (T a, T b, T tolerance=std::numeric_limits< T >::epsilon())
	Returns if a equals b, taking possible rounding errors into account.
template<typename T >
bool	NearZero (T a, T tolerance=std::numeric_limits< T >::epsilon())
	Returns if a equals zero, taking rounding errors into account.
template<typename T , typename = std::enable_if<std::is_integral<T>::value>>
bool	InRange (T var, T start, T end)
	Test if a variable is in a specific range, using an optimized technique that requires only one branch.
template<typename T >
QuadraticSolution< T >	SolveQuadratic (T a, T b, T c)
	Solve a quadratic equation.
std::ostream &	operator<< (std::ostream &os, const ParseError &error)
	Ostream output operator for ParseError, outputs the error message.
	MATCHER_P (ToStringIs, expected, "")
	Matches the string representation of an object, by calling testing::PrintToString and comparing the results with the expected value.
	MATCHER_P2 (Vector2Eq, xMatcher, yMatcher, "")
	Matches a Vector.
	MATCHER_P2 (Vector2Near, xValue, yValue, "")
	Matches a Vector2 with DoubleNear(0.01).
	MATCHER_P (NormalizedEq, expectedVector, "")
	Matches if two vectors are equal when both are normalized, within an error of 0.01.
	MATCHER_P (TransformEq, other, "transform eq "+testing::PrintToString(other))
	Matches a transform with near-equals comparison.
	MATCHER_P6 (TransformIs, d0, d1, d2, d3, d4, d5, "")
	Matches a transform per-element, with a near-equals comparison using a threshold of 0.0001.
	MATCHER (TransformIsIdentity, "")
	Matches if a transform is identity.
	MATCHER_P2 (BoxEq, topLeftMatcher, bottomRightMatcher, "")
	Matches a Box.
	MATCHER_P2 (LengthIs, valueMatcher, unitMatcher, "")
	Matches a Length.
template<typename T >
void	PrintTo (const ParseResult< T > &result, std::ostream *os)
	Outputs a ParseResult to a stream for debugging purposes.
	MATCHER (NoParseError, "")
	Matches if the result does not contain a ParseError.
	MATCHER_P (ParseErrorIs, errorMessageMatcher, std::string("parse error is (")+testing::PrintToString(errorMessageMatcher)+")")
	Given a ParseResult, matches if it contains an error whose reason matches the given errorMessageMatcher (string or matcher).
	MATCHER_P2 (ParseErrorPos, lineMatcher, offsetMatcher, "")
	Given a ParseResult, matches if it contains an error at the given offset.
	MATCHER (ParseErrorEndOfString, "")
	Matches if a ParseResult contains an error at the end of the string.
	MATCHER_P (ParseResultIs, resultMatcher, "")
	Matches if a ParseResult contains a result that matches the given value, and that it does not contain an error.
	MATCHER_P2 (ParseResultAndError, resultMatcher, errorMessageMatcher, "")
	Matches if a ParseResult contains a result that matches the given value, and that it does not contain an error.

Detailed Description

Top-level Donner namespace, which is split into different sub-namespaces such as donner::svg and donner::css.

---

Class Documentation

donner::FileOffsetRange

struct donner::FileOffsetRange

Holds a selection range for a region in the source text.

Collaboration diagram for donner::FileOffsetRange:

Class Members
FileOffset	end	End offset.
FileOffset	start	Start offset.

donner::MathConstants

struct donner::MathConstants

template<typename T>
struct donner::MathConstants< T >

Contains a set of math constants for the specified type (float or double).

Template Parameters

T

donner::QuadraticSolution

struct donner::QuadraticSolution

template<typename T>
struct donner::QuadraticSolution< T >

Holds the solution of a quadratic equation, as returned by SolveQuadratic.

Template Parameters

T

Collaboration diagram for donner::QuadraticSolution< T >:

Class Members
bool	hasSolution = false	True if the equation has solutions.
array< T, 2 >	solution	Solutions to the equation, valid if hasSolution is true.

Typedef Documentation

Entity

using donner::Entity = entt::entity

Entity type for the Registry, a std::uint32_t alias.

This is a core type for the the ECS, and is used to identify entities in the Registry.

See also

Entity Component System (ECS)

Registry

EntityHandle

using donner::EntityHandle = entt::basic_handle<Registry>

Convenience handle for a Entity with an attached Registry.

Allows calling functions typically on Registry without having to pass around two values.

Registry

using donner::Registry = entt::basic_registry<Entity, std::allocator<Entity>>

Registry type for the SVG ECS, which is the entry point for storing all data.

It is used to create new entities:

Registry registry;
const Entity entity = registry.create();

Attach or remove data classes to entities:

registry.emplace<components::TreeComponent>(entity, "unknown");
registry.remove<components::TreeComponent>(entity);

Store global objects (singleton-like):

registry.ctx().emplace<components::RenderingContext>(registry));
const Entity root = registry.ctx().get<components::RenderingContext>().rootEntity;

See also

Entity Component System (ECS)

Enumeration Type Documentation

LengthUnit

enum class donner::LengthUnit

strong

The unit identifier for a length, corresponding to CSS unit identifiers.

See https://www.w3.org/TR/css-values-3/#lengths for definitions.

Enumerator
None	Unitless.
Percent	Percentage, using the '%' symbol.
Cm	Centimeters, 1cm = 96px/2.54.
Mm	Millimeters, 1mm = 1/10th of 1cm.
Q	Quarter-millimeters, 1Q = 1/40th of 1cm.
In	Inches, 1in = 2.54cm = 96px.
Pc	Picas, 1pc = 1/6th of 1in.
Pt	Points, 1pt = 1/72nd of 1in.
Px	Pixels, 1px = 1/96th of 1in.
Em	Font size, 1em = current font size.
Ex	x-height of the current font, 1ex = x-height of current font.
Ch	Width of the glyph '0' in the current font, 1ch = width of '0' in current font.
Rem	Root font size, 1rem = font size of the root element.
Vw	Viewport width, 1vw = 1% of viewport width.
Vh	Viewport height, 1vh = 1% of viewport height.
Vmin	Smaller of viewport width and height, 1vmin = 1% of smaller of viewport width and height.
Vmax	Larger of viewport width and height, 1vmax = 1% of larger of viewport width and height.

StringComparison

enum class donner::StringComparison : uint8_t

strong

String comparison options, e.g. case sensitivity.

Enumerator
Default	The default case-sensitive string comparison.
IgnoreCase	Case-insensitive string comparison.

Function Documentation

InRange()

template<typename T , typename = std::enable_if<std::is_integral<T>::value>>

bool donner::InRange ( T var, T start, T end )

inline

Test if a variable is in a specific range, using an optimized technique that requires only one branch.

Some compilers do this automatically.

Example:

if (InRange(var, 'a', 'z')) // ...

Lerp()

template<typename T >

T donner::Lerp ( T a, T b, const float t )

inline

Returns linear interpolation of a and b with ratio t.

Returns

a if t == 0, b if t == 1, and the linear interpolation else.

MATCHER_P() [1/5]

donner::MATCHER_P	(	NormalizedEq	,
		expectedVector	,
		""	)

Matches if two vectors are equal when both are normalized, within an error of 0.01.

Example:

EXPECT_THAT(Vector2d(1.0, 2.0), NormalizedEq(Vector2d(2.0, 4.0)));

Parameters

expectedVector

Expected value vector, which will be normalized.

MATCHER_P() [2/5]

donner::MATCHER_P	(	ParseErrorIs	,
		errorMessageMatcher	,
		std::string("parse error is (")+testing::PrintToString(errorMessageMatcher)+")"	)

Given a ParseResult, matches if it contains an error whose reason matches the given errorMessageMatcher (string or matcher).

Outputs a readable message on mismatch, e.g.: Expected: parse error is (starts with "Unexpected") Actual: parse error reason is "Failed to parse number: not finite"

Usage:

EXPECT_THAT(error, ParseErrorIs("My message"));
EXPECT_THAT(error, ParseErrorIs(StartsWith("Err")));

Parameters

errorMessageMatcher

Matcher to match the error message against, either a string or gmock matcher.

MATCHER_P() [3/5]

donner::MATCHER_P	(	ParseResultIs	,
		resultMatcher	,
		""	)

Matches if a ParseResult contains a result that matches the given value, and that it does not contain an error.

Parameters

resultMatcher

Value to match with.

MATCHER_P() [4/5]

donner::MATCHER_P	(	ToStringIs	,
		expected	,
		""	)

Matches the string representation of an object, by calling testing::PrintToString and comparing the results with the expected value.

Example:

EXPECT_THAT(myObject, ToStringIs("MyObject(foo)"));

Parameters

expected

Expected string representation.

MATCHER_P() [5/5]

donner::MATCHER_P	(	TransformEq	,
		other	,
		"transform eq "+	testing::PrintToStringother )

Matches a transform with near-equals comparison.

Example:

EXPECT_THAT(result, TransformEq(Transformd::Scale({2.0, 2.0})));

Parameters

other

Transform object to compare.

MATCHER_P2() [1/6]

donner::MATCHER_P2	(	BoxEq	,
		topLeftMatcher	,
		bottomRightMatcher	,
		""	)

Matches a Box.

Parameters

topLeftMatcher	Matcher for topLeft field.
bottomRightMatcher	Matcher for bottomRight field.

MATCHER_P2() [2/6]

donner::MATCHER_P2	(	LengthIs	,
		valueMatcher	,
		unitMatcher	,
		""	)

Matches a Length.

Example:

EXPECT_THAT(Length(10.0, Lengthd::Unit::Cm), LengthIs(10.0, Lengthd::Unit::Cm));

Parameters

valueMatcher	Matcher for value field.
unitMatcher	Matcher for unit field.

MATCHER_P2() [3/6]

donner::MATCHER_P2	(	ParseErrorPos	,
		lineMatcher	,
		offsetMatcher	,
		""	)

Given a ParseResult, matches if it contains an error at the given offset.

Parameters

lineMatcher	Line number of the error.
offsetMatcher	Column offset of the error.

MATCHER_P2() [4/6]

donner::MATCHER_P2	(	ParseResultAndError	,
		resultMatcher	,
		errorMessageMatcher	,
		""	)

Matches if a ParseResult contains a result that matches the given value, and that it does not contain an error.

Parameters

resultMatcher	Result to match with.
errorMessageMatcher	Parse error message to match with, either a string or a gmock matcher.

MATCHER_P2() [5/6]

donner::MATCHER_P2	(	Vector2Eq	,
		xMatcher	,
		yMatcher	,
		""	)

Matches a Vector.

Example:

EXPECT_THAT(Vector2i(1, 2), Vector2Eq(1, 2));

Parameters

xMatcher	X coordinate matcher.
yMatcher	Y coordinate matcher.

MATCHER_P2() [6/6]

donner::MATCHER_P2	(	Vector2Near	,
		xValue	,
		yValue	,
		""	)

Matches a Vector2 with DoubleNear(0.01).

Parameters

xValue	X coordinate, note that this is not a matcher.
yValue	Y coordinate, note that this is not a matcher.

MATCHER_P6()

donner::MATCHER_P6	(	TransformIs	,
		d0	,
		d1	,
		d2	,
		d3	,
		d4	,
		d5	,
		""	)

Matches a transform per-element, with a near-equals comparison using a threshold of 0.0001.

Example:

EXPECT_THAT(result, TransformIs(1.0, 0.0, 0.0, 1.0, 0.0, 0.0));

Parameters

d0	Corresponds to Transform::data[0]
d1	Corresponds to Transform::data[1]
d2	Corresponds to Transform::data[2]
d3	Corresponds to Transform::data[3]
d4	Corresponds to Transform::data[4]
d5	Corresponds to Transform::data[5]

NarrowToFloat()

float donner::NarrowToFloat ( double from )

inline

Semantically represent a narrowing conversion, such as converting a double to a float, to make the conversion more visible.

For example: const float f = NarrowToFloat(1.0);

parentsGenerator()

template<ElementLike T>

ElementTraversalGenerator< T > donner::parentsGenerator

(

T

element

)

A generator that yields all parents of an element, repeatedly following parentElement() until reaching the root.

Parameters

element

The element to start from, which is not yielded.

previousSiblingsGenerator()

template<ElementLike T>

ElementTraversalGenerator< T > donner::previousSiblingsGenerator

(

T

element

)

A generator that yields all siblings of an element, in reverse order.

This repeatedly follows previousSibling().

Parameters

element

The element to start from, which is not yielded.

singleElementGenerator()

template<ElementLike T>

ElementTraversalGenerator< T > donner::singleElementGenerator

(

T

element

)

A generator that yields a single element, if it exists.

Parameters

element

The element to yield. If this is std::nullopt, the generator will yield nothing.

SolveQuadratic()

template<typename T >

QuadraticSolution< T > donner::SolveQuadratic	(	T	a,
		T	b,
		T	c )

Solve a quadratic equation.

\( a x^2 + b x + c = 0 \)

Parameters

a	First coefficient.
b	Second coefficient.
c	Third coefficient.

Returns

QuadraticSolution, containing 0-2 solutions.