xtd::forms::style_sheets::length Class Reference

Inheritance diagram for xtd::forms::style_sheets::length:

Definition

The xtd::forms::style_sheets::length specifies the legth and unit of many properties of the xtd::forms::style_sheets::ibox_model.

class forms_export_ length : public xtd::iequatable<length>, public xtd::object

Inheritance

xtd::object → xtd::forms::style_sheets::length

Implements

xtd::iequatable <>

Header

#include <xtd/forms/style_sheets/lenght>

Namespace

xtd::forms::style_sheets

Library

xtd.forms

Remarks

CSS has several different units for expressing a length.

Many CSS properties take "length" values, such as width, margin, padding, font-size, etc.

Length is a number followed by a length unit, such as 10px, 2em, etc.CSS has several different units for expressing a length.

Example

Set different length values, using px (pixels):

control {
  border-width: 3px;
}
 
button {
  border-width: 1px;
  border-radius: 5px;
}

Note

A whitespace cannot appear between the number and the unit. However, if the value is 0, the unit can be omitted.

Remarks

For some CSS properties, negative lengths are allowed.

There are two types of length units: absolute and relative.

Absolute lengths

The absolute length units are fixed and a length expressed in any of these will appear as exactly that size.

Enum class value	Css potfix	Description
centimeters	cm	centimeters
millimeters	mm	millimeters
inches	in	inches (1in = 96px = 2.54cm)
pixels	px	pixels (1px = 1/96th of 1in)
points	pt	points (1pt = 1/72 of 1in)
picas	pc	picas (1pc = 12 pt)

Relative lengths

Relative length units specify a length relative to another length property. Relative length units scales better between different rendering mediums.

Enum class value	Css potfix	Description
element	em	Relative to the font-size of the element (2em means 2 times the size of the current font)
element_x_height	ex	Relative to the x-height of the current font (rarely used)
chase	ch	Relative to width of the "0" (zero)
root_element	rem	Relative to font-size of the root element
viewport_width	vw	Relative to 1% of the width of the viewport(*)
viewport_height	vh	Relative to 1% of the height of the viewport(*)
viewport_min	vmin	Relative to 1% of viewport's* smaller dimension
viewport_max	vmax	Relative to 1% of viewport's* larger dimension
percent	%	Relative to the parent element

Note

The element(em) and root_element(rem) units are practical in creating perfectly scalable layout! (*) Viewport = the bounds of the element. If the viewport is 50cm wide, 1vw = 0.5cm.

Public Fields
static const length	empty
	Provides a xtd::forms::style_sheets::length object with 0 pixels.

Public Constructors
	length ()=default
	Initializes a new instance of the xtd::forms::style_sheets::length class.
	length (double value)
	Initializes a new instance of the xtd::forms::style_sheets::length class with specifed value in pixels.
	length (double value, length_unit unit)
	Initializes a new instance of the xtd::forms::style_sheets::length class with specifed value and unit.

Peorperties
double	value () const noexcept
	Gets the xtd::forms::style_sheets::length value.
void	value (double value) noexcept
	Sets the xtd::forms::style_sheets::length value.
length_unit	unit () const noexcept
	Gets the xtd::forms::style_sheets::length unit.
void	unit (length_unit value) noexcept
	Sets the xtd::forms::style_sheets::length unit.

Public Methods
bool	equals (const length &other) const noexcept override
int32	get_pixels (const xtd::drawing::rectangle &rect) const noexcept
	Gets the legnth in pixels.
xtd::string	to_string () const noexcept override
	Returns a xtd::string that represents the current object.
virtual bool	equals (const object &obj) const noexcept
	Determines whether the specified object is equal to the current object.
template<typename object_a_t , typename object_b_t >
static bool	equals (const object_a_t &object_a, const object_b_t &object_b) noexcept
	Determines whether the specified object instances are considered equal.

Additional Inherited Members
Public Member Functions inherited from xtd::iequatable< length >
virtual bool	equals (const length &) const noexcept=0
	Indicates whether the current object is equal to another object of the same type.
Public Member Functions inherited from xtd::object
	object ()=default
	Create a new instance of the ultimate base class object.
virtual size_t	get_hash_code () const noexcept
	Serves as a hash function for a particular type.
virtual type_object	get_type () const noexcept
	Gets the type of the current instance.
template<typename object_t >
xtd::uptr< object_t >	memberwise_clone () const
	Creates a shallow copy of the current object.
Static Public Member Functions inherited from xtd::object
template<typename object_a_t , typename object_b_t >
static bool	equals (const object_a_t &object_a, const object_b_t &object_b) noexcept
	Determines whether the specified object instances are considered equal.
template<typename object_a_t , typename object_b_t >
static bool	reference_equals (const object_a_t &object_a, const object_b_t &object_b) noexcept
	Determines whether the specified object instances are the same instance.

Constructor & Destructor Documentation

length() [1/3]

xtd::forms::style_sheets::length::length ( )

default

Initializes a new instance of the xtd::forms::style_sheets::length class.

length() [2/3]

xtd::forms::style_sheets::length::length ( double  value )

explicit

Initializes a new instance of the xtd::forms::style_sheets::length class with specifed value in pixels.

Parameters

value

The number of pixels to be used for xtd::forms::style_sheets::length.

length() [3/3]

xtd::forms::style_sheets::length::length	(	double	value,
		length_unit	unit
	)

Initializes a new instance of the xtd::forms::style_sheets::length class with specifed value and unit.

Parameters

value	The number of unit to be used for xtd::forms::style_sheets::length.
unit	One of xtd::forms::style_sheets::legth_unit values.

Member Function Documentation

value() [1/2]

double xtd::forms::style_sheets::length::value ( ) const

noexcept

Gets the xtd::forms::style_sheets::length value.

Returns

The value of the xtd::forms::style_sheets::length.

value() [2/2]

void xtd::forms::style_sheets::length::value ( double  value )

noexcept

Sets the xtd::forms::style_sheets::length value.

Parameters

value

The value of the xtd::forms::style_sheets::length.

unit() [1/2]

length_unit xtd::forms::style_sheets::length::unit ( ) const

noexcept

Gets the xtd::forms::style_sheets::length unit.

Returns

One of xtd::forms::style_sheets::legth_unit values.

unit() [2/2]

void xtd::forms::style_sheets::length::unit ( length_unit  value )

noexcept

Sets the xtd::forms::style_sheets::length unit.

Parameters

value

One of xtd::forms::style_sheets::legth_unit values.

get_pixels()

int32 xtd::forms::style_sheets::length::get_pixels ( const xtd::drawing::rectangle &  rect ) const

noexcept

Gets the legnth in pixels.

Parameters

rect	The xtd::drawing::rectangle is used to compute the length for relative length units.

Returns

The legnth in pixels.

to_string()

xtd::string xtd::forms::style_sheets::length::to_string ( ) const

overridevirtualnoexcept

Returns a xtd::string that represents the current object.

Returns

A string that represents the current object.

Examples

The following code example demonstrates what to_string returns.

#include <xtd/xtd>
 
using namespace xtd;
 
namespace examples {
  namespace object_test {
    class object1 : public object {
    };
  }
}
 
auto main() -> int {
  ptr<object> obj1 = new_ptr<examples::object_test::object1>();
  console::write_line(obj1->to_string());
 
  ptr<object> obj2 = new_ptr<date_time>(1971, 1, 5, 23, 5, 0);
  console::write_line(obj2->to_string());
 
  ptr<object> obj3 = new_ptr<boolean_object>();
  console::write_line(obj3->to_string());
}
 
// This code produces the following output :
//
// examples::object_test::object1
// Tue Jan  5 23:05:00 1971
// false

Reimplemented from xtd::object.

equals() [1/2]

virtual bool xtd::object::equals ( const object &  obj ) const

virtualnoexcept

Determines whether the specified object is equal to the current object.

Parameters

obj	The object to compare with the current object.

Returns

true if the specified object is equal to the current object. otherwise, false.

Examples

The following code example compares the current instance with another object.

#include <xtd/console>
 
using namespace xtd;
 
auto main() -> int {
  auto object1 = new_ptr<object>();
  auto object2 = new_ptr<object>();
  
  auto object3 = object2;
  console::write_line(object1->equals(*object3));
  console::write_line(*object1 == *object3);
  object3 = object1;
  console::write_line(object1->equals(*object3));
  console::write_line(*object1 == *object3);
}
 
// This code produces the following output :
//
// false
// false
// true
// true

Reimplemented from xtd::object.

equals() [2/2]

template<typename object_a_t , typename object_b_t >

static bool xtd::object::equals ( const object_a_t &  object_a, const object_b_t &  object_b  )

inlinestaticnoexcept

Determines whether the specified object instances are considered equal.

Parameters

object_a	The first object to compare.
object_b	The second object to compare.

Returns

true if object_a is the same instance as object_b or if both are null references or if object_a(object_b) returns true. otherwise, false.

Examples

The following code example compares different objects.

#include <xtd/console>
 
using namespace xtd;
 
auto main() -> int {
  string s1 = "Tom";
  string s2 = "Carol";
  console::write_line("object::equals(\"{0}\", \"{1}\") => {2}", s1, s2, object::equals(s1, s2));
  
  s1 = "Tom";
  s2 = "Tom";
  console::write_line("object::equals(\"{0}\", \"{1}\") => {2}", s1, s2, object::equals(s1, s2));
  
  s1 = "";
  s2 = "Tom";
  console::write_line("object::equals(\"{0}\", \"{1}\") => {2}", s1, s2, object::equals(s1, s2));
  
  s1 = "Carol";
  s2 = "";
  console::write_line("object::equals(\"{0}\", \"{1}\") => {2}", s1, s2, object::equals(s1, s2));
  
  s1 = "";
  s2 = "";
  console::write_line("object::equals(\"{0}\", \"{1}\") => {2}", s1, s2, object::equals(s1, s2));
}
 
// This code produces the following output :
//
// object::equals("Tom", "Carol") => false
// object::equals("Tom", "Tom") => true
// object::equals("", "Tom") => false
// object::equals("Carol", "") => false
// object::equals("", "") => true

Member Data Documentation

empty

const length xtd::forms::style_sheets::length::empty

static

Provides a xtd::forms::style_sheets::length object with 0 pixels.

---

The documentation for this class was generated from the following file:

• xtd.forms/include/xtd/forms/style_sheets/length.hpp