AbsoluteOrRelativeValue.hpp

 
//
// TGUI - Texus' Graphical User Interface
// Copyright (C) 2012-2020 Bruno Van de Velde (vdv_b@tgui.eu)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
// you must not claim that you wrote the original software.
// If you use this software in a product, an acknowledgment
// in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
// and must not be misrepresented as being the original software.
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// 3. This notice may not be removed or altered from any source distribution.
//
 
 
#ifndef TGUI_ABSOLUTE_OR_RELATIVE_VALUE_HPP
#define TGUI_ABSOLUTE_OR_RELATIVE_VALUE_HPP
 
#include <TGUI/Global.hpp>
#include <TGUI/to_string.hpp>
#include <type_traits>
#include <string>
 
 
namespace tgui
{
 class TGUI_API AbsoluteOrRelativeValue
 {
 public:
 
 TGUI_CONSTEXPR AbsoluteOrRelativeValue()
 {
 // Constructor isn't defined as "= default" because this leads to an IntelliSense error
 }
 
 
 template <typename T, typename = typename std::enable_if<std::is_arithmetic<T>::value, T>::type>
 TGUI_CONSTEXPR AbsoluteOrRelativeValue(T constant) :
 m_constant {true},
 m_value {static_cast<float>(constant)}
 {
 }
 
 
 AbsoluteOrRelativeValue(const char* expression) :
 AbsoluteOrRelativeValue{std::string{expression}}
 {
 }
 
 
 AbsoluteOrRelativeValue(const std::string& expression)
 {
 if (!expression.empty() && (expression.back() == '%'))
 {
 m_constant = false;
 m_ratio = strToFloat(expression.substr(0, expression.length()-1)) / 100.f;
 }
 else
 {
 m_constant = true;
 m_value = strToFloat(expression.substr(0, expression.length()));
 }
 }
 
 
 TGUI_CONSTEXPR float getValue() const
 {
 return m_value;
 }
 
 
 TGUI_CONSTEXPR float getRatio() const
 {
 return m_ratio;
 }
 
 
 TGUI_CONSTEXPR bool isConstant() const
 {
 return m_constant;
 }
 
 
 void updateParentSize(float newParentSize)
 {
 if (!m_constant)
 {
 m_parentValue = newParentSize;
 m_value = m_ratio * newParentSize;
 }
 }
 
 
 std::string toString() const
 {
 if (m_constant)
 return to_string(m_value);
 else
 return to_string(m_ratio * 100) + '%';
 }
 
 
 protected:
 
 bool m_constant = true;
 float m_value = 0;
 float m_ratio = 0;
 float m_parentValue = 0;
 };
 
 
 struct TGUI_API RelativeValue : AbsoluteOrRelativeValue
 {
 explicit TGUI_CONSTEXPR RelativeValue(float ratio)
 {
 m_constant = false;
 m_ratio = ratio;
 }
 };
 
}
 
 
#endif // TGUI_ABSOLUTE_OR_RELATIVE_VALUE_HPP