Files
yoga/YogaKit/YKLayout.m
2016-12-19 01:13:16 +01:00

295 lines
9.7 KiB
Objective-C

/**
* 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.
*/
#import <UIKit/UIKit.h>
#import <YogaKit/UIView+YogaKit.h>
#import <YogaKit/YKLayout.h>
#import <YogaKit/yoga.h>
#define YK_STYLE_PROPERTY_IMPL(objc_type, c_type, lowercased_name, capitalized_name) \
- (objc_type)lowercased_name \
{ \
return (objc_type)YGNodeStyleGet##capitalized_name(_node); \
} \
\
- (void)set##capitalized_name:(objc_type)lowercased_name \
{ \
YGNodeStyleSet##capitalized_name(_node, (c_type)lowercased_name); \
}
#define _YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, edge) \
- (CGFloat)lowercased_name##edge \
{ \
return YGNodeStyleGet##capitalized_name(_node, YGEdge##edge); \
} \
\
- (void)set##capitalized_name##edge:(CGFloat)lowercased_name##edge \
{ \
YGNodeStyleSet##capitalized_name(_node, YGEdge##edge, lowercased_name##edge); \
}
#define YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, Left) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, Top) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, Right) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, Bottom) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, Start) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, End) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, Horizontal) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, Vertical) \
_YK_STYLE_EDGE_PROPERTY_IMPL(lowercased_name, capitalized_name, All)
@interface YKLayout ()
@property (nonatomic, weak, readonly) UIView* view;
@property (nonatomic, assign, readonly) YGNodeRef node;
@end
@implementation YKLayout
@synthesize isEnabled=_isEnabled;
@synthesize isIncluded=_isIncluded;
+ (void)initialize
{
YGSetExperimentalFeatureEnabled(YGExperimentalFeatureWebFlexBasis, true);
}
- (instancetype)initWithView:(UIView*)view
{
if ([super init]) {
_view = view;
_node = YGNodeNew();
YGNodeSetContext(_node, (__bridge void *) view);
_isEnabled = NO;
_isIncluded = YES;
}
return self;
}
- (void)dealloc
{
YGNodeFree(_node);
}
- (NSUInteger)numberOfChildren
{
return YGNodeGetChildCount(_node);
}
YK_STYLE_PROPERTY_IMPL(YKDirection, YGDirection, direction, Direction)
YK_STYLE_PROPERTY_IMPL(YKFlexDirection, YGFlexDirection, flexDirection, FlexDirection)
YK_STYLE_PROPERTY_IMPL(YKJustify, YGJustify, justifyContent, JustifyContent)
YK_STYLE_PROPERTY_IMPL(YKAlign, YGAlign, alignContent, AlignContent)
YK_STYLE_PROPERTY_IMPL(YKAlign, YGAlign, alignItems, AlignItems)
YK_STYLE_PROPERTY_IMPL(YKAlign, YGAlign, alignSelf, AlignSelf)
YK_STYLE_PROPERTY_IMPL(YKPositionType, YGPositionType, positionType, PositionType)
YK_STYLE_PROPERTY_IMPL(YKWrap, YGWrap, flexWrap, FlexWrap)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, flexGrow, FlexGrow)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, flexShrink, FlexShrink)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, flexBasis, FlexBasis)
YK_STYLE_EDGE_PROPERTY_IMPL(position, Position)
YK_STYLE_EDGE_PROPERTY_IMPL(margin, Margin)
YK_STYLE_EDGE_PROPERTY_IMPL(padding, Padding)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, width, Width)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, height, Height)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, minWidth, MinWidth)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, minHeight, MinHeight)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, maxWidth, MaxWidth)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, maxHeight, MaxHeight)
YK_STYLE_PROPERTY_IMPL(CGFloat, CGFloat, aspectRatio, AspectRatio)
#pragma mark - Layout and Sizing
- (YKDirection)resolvedDirection
{
return (YKDirection)YGNodeLayoutGetDirection(_node);
}
- (void)apply
{
[self calculateLayoutWithSize:self.view.bounds.size];
YKApplyLayoutToViewHierarchy(self);
}
- (CGSize)intrinsicSize
{
const CGSize constrainedSize = {
.width = YGUndefined,
.height = YGUndefined,
};
return [self calculateLayoutWithSize:constrainedSize];
}
#pragma mark - Private
- (CGSize)calculateLayoutWithSize:(CGSize)size
{
NSAssert([NSThread isMainThread], @"YG Layout calculation must be done on main.");
NSAssert([self isEnabled], @"YG Layout is not enabled for this view.");
YKAttachNodesFromViewHierachy(self);
const YGNodeRef node = _node;
YGNodeCalculateLayout(
node,
size.width,
size.height,
YGNodeStyleGetDirection(node));
return (CGSize) {
.width = YGNodeLayoutGetWidth(node),
.height = YGNodeLayoutGetHeight(node),
};
}
static YGSize YKMeasureView(
YGNodeRef node,
float width,
YGMeasureMode widthMode,
float height,
YGMeasureMode heightMode)
{
const CGFloat constrainedWidth = (widthMode == YGMeasureModeUndefined) ? CGFLOAT_MAX : width;
const CGFloat constrainedHeight = (heightMode == YGMeasureModeUndefined) ? CGFLOAT_MAX: height;
UIView *view = (__bridge UIView*) YGNodeGetContext(node);
const CGSize sizeThatFits = [view sizeThatFits:(CGSize) {
.width = constrainedWidth,
.height = constrainedHeight,
}];
return (YGSize) {
.width = YKSanitizeMeasurement(constrainedWidth, sizeThatFits.width, widthMode),
.height = YKSanitizeMeasurement(constrainedHeight, sizeThatFits.height, heightMode),
};
}
static CGFloat YKSanitizeMeasurement(
CGFloat constrainedSize,
CGFloat measuredSize,
YGMeasureMode measureMode)
{
CGFloat result;
if (measureMode == YGMeasureModeExactly) {
result = constrainedSize;
} else if (measureMode == YGMeasureModeAtMost) {
result = MIN(constrainedSize, measuredSize);
} else {
result = measuredSize;
}
return result;
}
static void YKAttachNodesFromViewHierachy(YKLayout *layout) {
YGNodeRef node = layout.node;
UIView *view = layout.view;
// Only leaf nodes should have a measure function
if (![layout isEnabled] || view.subviews.count == 0) {
YGNodeSetMeasureFunc(node, YKMeasureView);
YKRemoveAllChildren(node);
} else {
YGNodeSetMeasureFunc(node, NULL);
// Create a list of all the subviews that we are going to use for layout.
NSMutableArray<UIView *> *subviewsToInclude = [[NSMutableArray alloc] initWithCapacity:view.subviews.count];
for (UIView *subview in view.subviews) {
if (subview.layout.isIncluded) {
[subviewsToInclude addObject:subview];
}
}
BOOL shouldReconstructChildList = NO;
if (YGNodeGetChildCount(node) != subviewsToInclude.count) {
shouldReconstructChildList = YES;
} else {
for (int i = 0; i < subviewsToInclude.count; i++) {
if (YGNodeGetChild(node, i) != subviewsToInclude[i].layout.node) {
shouldReconstructChildList = YES;
break;
}
}
}
if (shouldReconstructChildList) {
YKRemoveAllChildren(node);
for (int i = 0 ; i < subviewsToInclude.count; i++) {
UIView *const subview = subviewsToInclude[i];
YGNodeInsertChild(node, subview.layout.node, i);
YKAttachNodesFromViewHierachy(subview.layout);
}
}
}
}
static void YKRemoveAllChildren(const YGNodeRef node)
{
if (node == NULL) {
return;
}
while (YGNodeGetChildCount(node) > 0) {
YGNodeRemoveChild(node, YGNodeGetChild(node, YGNodeGetChildCount(node) - 1));
}
}
static CGFloat YKRoundPixelValue(CGFloat value)
{
static CGFloat scale;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^(){
scale = [UIScreen mainScreen].scale;
});
return round(value * scale) / scale;
}
static void YKApplyLayoutToViewHierarchy(YKLayout *layout) {
NSCAssert([NSThread isMainThread], @"Framesetting should only be done on the main thread.");
if (!layout.isIncluded) {
return;
}
YGNodeRef node = layout.node;
const CGPoint topLeft = {
YGNodeLayoutGetLeft(node),
YGNodeLayoutGetTop(node),
};
const CGPoint bottomRight = {
topLeft.x + YGNodeLayoutGetWidth(node),
topLeft.y + YGNodeLayoutGetHeight(node),
};
UIView *view = layout.view;
view.frame = (CGRect) {
.origin = {
.x = YKRoundPixelValue(topLeft.x),
.y = YKRoundPixelValue(topLeft.y),
},
.size = {
.width = YKRoundPixelValue(bottomRight.x) - YKRoundPixelValue(topLeft.x),
.height = YKRoundPixelValue(bottomRight.y) - YKRoundPixelValue(topLeft.y),
},
};
const BOOL isLeaf = !layout.isEnabled || view.subviews.count == 0;
if (!isLeaf) {
for (NSUInteger i = 0; i < view.subviews.count; i++) {
YKApplyLayoutToViewHierarchy(view.subviews[i].layout);
}
}
}
@end