Swiftgram/AsyncDisplayKit/Layout/ASDimension.h

//
//  ASDimension.h
//  AsyncDisplayKit
//
//  Copyright (c) 2014-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under the BSD-style license found in the
//  LICENSE file in the root directory of this source tree. An additional grant
//  of patent rights can be found in the PATENTS file in the same directory.
//

#pragma once
#import <Foundation/Foundation.h>
#import <CoreGraphics/CoreGraphics.h>
#import <AsyncDisplayKit/ASBaseDefines.h>
#import <AsyncDisplayKit/ASAssert.h>

ASDISPLAYNODE_EXTERN_C_BEGIN
NS_ASSUME_NONNULL_BEGIN

#pragma mark -

ASDISPLAYNODE_INLINE BOOL AS_WARN_UNUSED_RESULT ASPointsValidForLayout(CGFloat points)
{
  return ((isnormal(points) || points == 0.0) && points >= 0.0 && points < (CGFLOAT_MAX / 2.0));
}

ASDISPLAYNODE_INLINE BOOL AS_WARN_UNUSED_RESULT ASIsCGSizeValidForLayout(CGSize size)
{
  return (ASPointsValidForLayout(size.width) && ASPointsValidForLayout(size.height));
}

ASDISPLAYNODE_INLINE BOOL AS_WARN_UNUSED_RESULT ASPointsValidForSize(CGFloat points)
{
  return ((isnormal(points) || points == 0.0) && points >= 0.0 && points < (FLT_MAX / 2.0));
}

ASDISPLAYNODE_INLINE BOOL AS_WARN_UNUSED_RESULT ASIsCGSizeValidForSize(CGSize size)
{
  return (ASPointsValidForSize(size.width) && ASPointsValidForSize(size.height));
}

#pragma mark - ASDimension

/**
 * A dimension relative to constraints to be provided in the future.
 * A ASDimension can be one of three types:
 *
 * "Auto" - This indicated "I have no opinion" and may be resolved in whatever way makes most sense given the circumstances.
 *
 * "Points" - Just a number. It will always resolve to exactly this amount.
 *
 * "Percent" - Multiplied to a provided parent amount to resolve a final amount.
 */
typedef NS_ENUM(NSInteger, ASDimensionUnit) {
  /** This indicates "I have no opinion" and may be resolved in whatever way makes most sense given the circumstances. */
  ASDimensionUnitAuto,
  /** Just a number. It will always resolve to exactly this amount. This is the default type. */
  ASDimensionUnitPoints,
  /** Multiplied to a provided parent amount to resolve a final amount. */
  ASDimensionUnitFraction,
};

typedef struct {
  ASDimensionUnit unit;
  CGFloat value;
} ASDimension;

/**
 * Represents auto as ASDimension
 */
extern ASDimension const ASDimensionAuto;

/**
 * Returns a dimension with the specified type and value.
 */
ASOVERLOADABLE ASDISPLAYNODE_INLINE ASDimension ASDimensionMake(ASDimensionUnit unit, CGFloat value)
{
  if (unit == ASDimensionUnitAuto ) {
    ASDisplayNodeCAssert(value == 0, @"ASDimension auto value must be 0.");
  } else if (unit == ASDimensionUnitPoints) {
    ASDisplayNodeCAssertPositiveReal(@"Points", value);
  } else if (unit == ASDimensionUnitFraction) {
    ASDisplayNodeCAssert( 0 <= value && value <= 1.0, @"ASDimension fraction value (%f) must be between 0 and 1.", value);
  }
  ASDimension dimension;
  dimension.unit = unit;
  dimension.value = value;
  return dimension;
}

/**
 * Returns a dimension with the specified points value.
 */
ASOVERLOADABLE ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT ASDimension ASDimensionMake(CGFloat points)
{
  return ASDimensionMake(ASDimensionUnitPoints, points);
}

/**
 * Returns a dimension by parsing the specified dimension string.
 * Examples: ASDimensionMake(@"50%") = ASDimensionMake(ASDimensionUnitFraction, 0.5)
 *           ASDimensionMake(@"0.5pt") = ASDimensionMake(ASDimensionUnitPoints, 0.5)
 */
ASOVERLOADABLE AS_WARN_UNUSED_RESULT extern ASDimension ASDimensionMake(NSString *dimension);

/**
 * Returns a dimension with the specified points value.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT ASDimension ASDimensionMakeWithPoints(CGFloat points)
{
  ASDisplayNodeCAssertPositiveReal(@"Points", points);
  return ASDimensionMake(ASDimensionUnitPoints, points);
}

/**
 * Returns a dimension with the specified fraction value.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT ASDimension ASDimensionMakeWithFraction(CGFloat fraction)
{
  ASDisplayNodeCAssert( 0 <= fraction && fraction <= 1.0, @"ASDimension fraction value (%f) must be between 0 and 1.", fraction);
  return ASDimensionMake(ASDimensionUnitFraction, fraction);
}

/**
 * Returns whether two dimensions are equal.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT BOOL ASDimensionEqualToDimension(ASDimension lhs, ASDimension rhs)
{
  return (lhs.unit == rhs.unit && lhs.value == rhs.value);
}

/**
 * Returns a NSString representation of a dimension.
 */
extern AS_WARN_UNUSED_RESULT NSString *NSStringFromASDimension(ASDimension dimension);

/**
 * Resolve this dimension to a parent size.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT CGFloat ASDimensionResolve(ASDimension dimension, CGFloat parentSize, CGFloat autoSize)
{
  switch (dimension.unit) {
    case ASDimensionUnitAuto:
      return autoSize;
    case ASDimensionUnitPoints:
      return dimension.value;
    case ASDimensionUnitFraction:
      return dimension.value * parentSize;
  }
}

#pragma mark - ASLayoutSize

/**
 * Expresses a size with relative dimensions. Only used for calculations internally in ASDimension.h
 */
typedef struct {
  ASDimension width;
  ASDimension height;
} ASLayoutSize;

extern ASLayoutSize const ASLayoutSizeAuto;

/*
 * Creates an ASLayoutSize with provided min and max dimensions.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT ASLayoutSize ASLayoutSizeMake(ASDimension width, ASDimension height)
{
  ASLayoutSize size;
  size.width = width;
  size.height = height;
  return size;
}

/**
 * Resolve this relative size relative to a parent size.
 */
ASDISPLAYNODE_INLINE CGSize ASLayoutSizeResolveSize(ASLayoutSize layoutSize, CGSize parentSize, CGSize autoSize)
{
  return CGSizeMake(ASDimensionResolve(layoutSize.width, parentSize.width, autoSize.width),
                    ASDimensionResolve(layoutSize.height, parentSize.height, autoSize.height));
}

/*
 * Returns a string representation of a relative size.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT NSString *NSStringFromASLayoutSize(ASLayoutSize size)
{
  return [NSString stringWithFormat:@"{%@, %@}",
          NSStringFromASDimension(size.width),
          NSStringFromASDimension(size.height)];
}

#pragma mark - ASEdgeInsets

typedef struct {
  ASDimension top;
  ASDimension left;
  ASDimension bottom;
  ASDimension right;
} ASEdgeInsets;

#pragma mark - ASSizeRange

/**
 * Expresses an inclusive range of sizes. Used to provide a simple constraint to layout.
 */
typedef struct {
  CGSize min;
  CGSize max;
} ASSizeRange;

/**
 * A size range with all dimensions zero.
 */
extern ASSizeRange const ASSizeRangeZero;

/**
 * A size range from zero to infinity in both directions.
 */
extern ASSizeRange const ASSizeRangeUnconstrained;

/**
 * Returns whether a size range has > 0.1 max width and max height.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT BOOL ASSizeRangeHasSignificantArea(ASSizeRange sizeRange)
{
  static CGFloat const limit = 0.1;
  return (sizeRange.max.width > limit && sizeRange.max.height > limit);
}

/**
 * Creates an ASSizeRange with provided min and max size.
 */
ASOVERLOADABLE ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT ASSizeRange ASSizeRangeMake(CGSize min, CGSize max)
{
  ASDisplayNodeCAssertPositiveReal(@"Range min width", min.width);
  ASDisplayNodeCAssertPositiveReal(@"Range min height", min.height);
  ASDisplayNodeCAssertInfOrPositiveReal(@"Range max width", max.width);
  ASDisplayNodeCAssertInfOrPositiveReal(@"Range max height", max.height);
  ASDisplayNodeCAssert(min.width <= max.width,
                       @"Range min width (%f) must not be larger than max width (%f).", min.width, max.width);
  ASDisplayNodeCAssert(min.height <= max.height,
                       @"Range min height (%f) must not be larger than max height (%f).", min.height, max.height);
  ASSizeRange sizeRange;
  sizeRange.min = min;
  sizeRange.max = max;
  return sizeRange;
}

/**
 * Creates an ASSizeRange with provided size as both min and max.
 */
ASOVERLOADABLE ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT ASSizeRange ASSizeRangeMake(CGSize exactSize)
{
  return ASSizeRangeMake(exactSize, exactSize);
}

/**
 * Clamps the provided CGSize between the [min, max] bounds of this ASSizeRange.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT CGSize ASSizeRangeClamp(ASSizeRange sizeRange, CGSize size)
{
  return CGSizeMake(MAX(sizeRange.min.width, MIN(sizeRange.max.width, size.width)),
                    MAX(sizeRange.min.height, MIN(sizeRange.max.height, size.height)));
}

/**
 * Intersects another size range. If the other size range does not overlap in either dimension, this size range
 * "wins" by returning a single point within its own range that is closest to the non-overlapping range.
 */
extern AS_WARN_UNUSED_RESULT ASSizeRange ASSizeRangeIntersect(ASSizeRange sizeRange, ASSizeRange otherSizeRange);

/**
 * Returns whether two size ranges are equal in min and max size.
 */
ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT BOOL ASSizeRangeEqualToSizeRange(ASSizeRange lhs, ASSizeRange rhs)
{
  return CGSizeEqualToSize(lhs.min, rhs.min) && CGSizeEqualToSize(lhs.max, rhs.max);
}

/**
 * Returns a string representation of a size range
 */
extern AS_WARN_UNUSED_RESULT NSString *NSStringFromASSizeRange(ASSizeRange sizeRange);

NS_ASSUME_NONNULL_END
ASDISPLAYNODE_EXTERN_C_END