dfc15780c7
This pull request introduces the `til::math` namespace, which provides some casting functions to be used in support of `til::point` and `til::size`. When point/size want to ingest a floating-point structure, they _must_ be instructed on how to convert those floating-point values into integers.
This enables:
```
Windows::Foundation::Point wfPoint = /* ... */;
til::point tp{ til::math::rounding, wfPoint };
```
Future thoughts: should the TilMath types be stackable? Right now, you cannot get "checked + rounding" behavior (where it throws if it doesn't fit) so everything is saturating.
## PR Checklist
* [x] Closes a request by Michael
* [x] I've discussed this with core contributors already
86 lines
3 KiB
C++
86 lines
3 KiB
C++
// Copyright (c) Microsoft Corporation.
|
|
// Licensed under the MIT license.
|
|
|
|
#pragma once
|
|
|
|
namespace til
|
|
{
|
|
// The til::math namespace contains TIL math guidance casts;
|
|
// they are intended to be used as the first argument to
|
|
// floating-point universal converters elsewhere in the til namespace.
|
|
namespace math
|
|
{
|
|
namespace details
|
|
{
|
|
struct ceiling_t
|
|
{
|
|
template<typename O, typename T>
|
|
static O cast(T val)
|
|
{
|
|
if constexpr (std::is_floating_point_v<T>)
|
|
{
|
|
THROW_HR_IF(E_ABORT, ::std::isnan(val));
|
|
return ::base::saturated_cast<O>(::std::ceil(val));
|
|
}
|
|
else
|
|
{
|
|
return ::base::saturated_cast<O>(val);
|
|
}
|
|
}
|
|
};
|
|
|
|
struct flooring_t
|
|
{
|
|
template<typename O, typename T>
|
|
static O cast(T val)
|
|
{
|
|
if constexpr (std::is_floating_point_v<T>)
|
|
{
|
|
THROW_HR_IF(E_ABORT, ::std::isnan(val));
|
|
return ::base::saturated_cast<O>(::std::floor(val));
|
|
}
|
|
else
|
|
{
|
|
return ::base::saturated_cast<O>(val);
|
|
}
|
|
}
|
|
};
|
|
|
|
struct rounding_t
|
|
{
|
|
template<typename O, typename T>
|
|
static O cast(T val)
|
|
{
|
|
if constexpr (std::is_floating_point_v<T>)
|
|
{
|
|
THROW_HR_IF(E_ABORT, ::std::isnan(val));
|
|
return ::base::saturated_cast<O>(::std::round(val));
|
|
}
|
|
else
|
|
{
|
|
return ::base::saturated_cast<O>(val);
|
|
}
|
|
}
|
|
};
|
|
|
|
struct truncating_t
|
|
{
|
|
template<typename O, typename T>
|
|
static O cast(T val)
|
|
{
|
|
if constexpr (std::is_floating_point_v<T>)
|
|
{
|
|
THROW_HR_IF(E_ABORT, ::std::isnan(val));
|
|
}
|
|
return ::base::saturated_cast<O>(val);
|
|
}
|
|
};
|
|
}
|
|
|
|
static constexpr details::ceiling_t ceiling; // positives become more positive, negatives become less negative
|
|
static constexpr details::flooring_t flooring; // positives become less positive, negatives become more negative
|
|
static constexpr details::rounding_t rounding; // it's rounding, from math class
|
|
static constexpr details::truncating_t truncating; // drop the decimal point, regardless of how close it is to the next value
|
|
}
|
|
}
|