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/*
* Copyright 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <algorithm>
#include <cstdint>
#include <limits>
#include <ostream>
#include <type_traits>
#include <utility>
#include <ui/Rotation.h>
namespace android::ui {
// A simple value type representing a two-dimensional size.
struct Size {
int32_t width = -1;
int32_t height = -1;
constexpr Size() = default;
template <typename T>
constexpr Size(T w, T h) : width(clamp<int32_t>(w)), height(clamp<int32_t>(h)) {}
int32_t getWidth() const { return width; }
int32_t getHeight() const { return height; }
// Valid means non-negative width and height
bool isValid() const { return width >= 0 && height >= 0; }
// Empty means zero width and height
bool isEmpty() const;
template <typename T>
void setWidth(T v) {
width = clamp<int32_t>(v);
}
template <typename T>
void setHeight(T v) {
height = clamp<int32_t>(v);
}
void set(Size size) { *this = size; }
template <typename T>
void set(T w, T h) {
set(Size(w, h));
}
// Applies a rotation onto the size
void rotate(Rotation rotation) {
if (rotation == ROTATION_90 || rotation == ROTATION_270) {
transpose();
}
}
// Swaps the width and height, emulating a 90 degree rotation.
void transpose() { std::swap(width, height); }
// Sets the value to kInvalidSize
void makeInvalid();
// Sets the value to kEmptySize
void clear();
// TODO: Replace with std::remove_cvref_t in C++20.
template <typename T>
using remove_cvref_t = std::remove_cv_t<std::remove_reference_t<T>>;
// Takes a value of type FromType, and ensures it can be represented as a value of type ToType,
// clamping the input value to the output range if necessary.
template <typename ToType, typename FromType>
static constexpr remove_cvref_t<ToType> clamp(FromType v) {
using BareToType = remove_cvref_t<ToType>;
using ToLimits = std::numeric_limits<BareToType>;
using BareFromType = remove_cvref_t<FromType>;
using FromLimits = std::numeric_limits<BareFromType>;
static_assert(ToLimits::is_specialized && FromLimits::is_specialized);
constexpr auto toHighest = ToLimits::max();
constexpr auto toLowest = ToLimits::lowest();
constexpr auto fromHighest = FromLimits::max();
constexpr auto fromLowest = FromLimits::lowest();
// Get the closest representation of [toLowest, toHighest] in type
// FromType to use to clamp the input value before conversion.
// std::common_type<...> is used to get a value-preserving type for the
// top end of the range.
using CommonHighestType = std::common_type_t<BareToType, BareFromType>;
using CommonLimits = std::numeric_limits<CommonHighestType>;
// std::make_signed<std::common_type<...>> is used to get a
// value-preserving type for the bottom end of the range, except this is
// a bit trickier for non-integer types like float.
using CommonLowestType = std::conditional_t<
CommonLimits::is_integer,
std::make_signed_t<std::conditional_t<CommonLimits::is_integer, CommonHighestType,
int /* not used */>>,
CommonHighestType>;
// We can then compute the clamp range in a way that can be later
// trivially converted to either the 'from' or 'to' types, and be
// representable in either.
constexpr auto commonClampHighest = std::min(static_cast<CommonHighestType>(fromHighest),
static_cast<CommonHighestType>(toHighest));
constexpr auto commonClampLowest = std::max(static_cast<CommonLowestType>(fromLowest),
static_cast<CommonLowestType>(toLowest));
constexpr auto fromClampHighest = static_cast<BareFromType>(commonClampHighest);
constexpr auto fromClampLowest = static_cast<BareFromType>(commonClampLowest);
// A clamp is needed only if the range we are clamping to is not the
// same as the range of the input.
constexpr bool isClampNeeded =
(fromLowest != fromClampLowest) || (fromHighest != fromClampHighest);
// If a clamp is not needed, the conversion is just a trivial cast.
if constexpr (!isClampNeeded) {
return static_cast<BareToType>(v);
}
// Note: Clang complains about the value of INT32_MAX not being
// convertible back to int32_t from float if this is made "constexpr",
// when clamping a float value to an int32_t value. This is however
// covered by a test case to ensure the run-time cast works correctly.
const auto toClampHighest = static_cast<BareToType>(commonClampHighest);
const auto toClampLowest = static_cast<BareToType>(commonClampLowest);
// Otherwise clamping is done by using the already computed endpoints
// for each type.
if (v <= fromClampLowest) {
return toClampLowest;
}
return v >= fromClampHighest ? toClampHighest : static_cast<BareToType>(v);
}
};
constexpr Size kInvalidSize;
constexpr Size kEmptySize{0, 0};
inline void Size::makeInvalid() {
set(kInvalidSize);
}
inline void Size::clear() {
set(kEmptySize);
}
inline bool operator==(Size lhs, Size rhs) {
return lhs.width == rhs.width && lhs.height == rhs.height;
}
inline bool Size::isEmpty() const {
return *this == kEmptySize;
}
inline bool operator!=(Size lhs, Size rhs) {
return !(lhs == rhs);
}
inline bool operator<(Size lhs, Size rhs) {
// Orders by increasing width, then height.
if (lhs.width != rhs.width) return lhs.width < rhs.width;
return lhs.height < rhs.height;
}
// Defining PrintTo helps with Google Tests.
inline void PrintTo(Size size, std::ostream* stream) {
*stream << "Size(" << size.width << ", " << size.height << ')';
}
} // namespace android::ui
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