Swiftgram/lottie-ios/Classes/RenderSystem/AnimatorNodes/LOTRoundedRectAnimator.m

//
//  LOTRoundedRectAnimator.m
//  Lottie
//
//  Created by brandon_withrow on 7/19/17.
//  Copyright © 2017 Airbnb. All rights reserved.
//

#import "LOTRoundedRectAnimator.h"
#import "LOTPointInterpolator.h"
#import "LOTNumberInterpolator.h"
#import "CGGeometry+LOTAdditions.h"

@implementation LOTRoundedRectAnimator {
  LOTPointInterpolator *_centerInterpolator;
  LOTPointInterpolator *_sizeInterpolator;
  LOTNumberInterpolator *_cornerRadiusInterpolator;
  BOOL _reversed;
}

- (instancetype _Nonnull )initWithInputNode:(LOTAnimatorNode *_Nullable)inputNode
                             shapeRectangle:(LOTShapeRectangle *_Nonnull)shapeRectangle {
  self = [super initWithInputNode:inputNode keyName:shapeRectangle.keyname];
  if (self) {
    _centerInterpolator = [[LOTPointInterpolator alloc] initWithKeyframes:shapeRectangle.position.keyframes];
    _sizeInterpolator = [[LOTPointInterpolator alloc] initWithKeyframes:shapeRectangle.size.keyframes];
    _cornerRadiusInterpolator = [[LOTNumberInterpolator alloc] initWithKeyframes:shapeRectangle.cornerRadius.keyframes];
    _reversed = shapeRectangle.reversed;
  }
  return self;
}

- (NSDictionary *)valueInterpolators {
  return @{@"Size" : _sizeInterpolator,
           @"Position" : _centerInterpolator,
           @"Roundness" : _cornerRadiusInterpolator};
}

- (BOOL)needsUpdateForFrame:(NSNumber *)frame {
  return [_centerInterpolator hasUpdateForFrame:frame] || [_sizeInterpolator hasUpdateForFrame:frame] || [_cornerRadiusInterpolator hasUpdateForFrame:frame];
}

- (void)addCorner:(CGPoint)cornerPoint withRadius:(CGFloat)radius toPath:(LOTBezierPath *)path clockwise:(BOOL)clockwise {
  CGPoint currentPoint = path.currentPoint;
  
  CGFloat ellipseControlPointPercentage = 0.55228;
  
  if (cornerPoint.y == currentPoint.y) {
    // Moving east/west
    if (cornerPoint.x < currentPoint.x) {
      // Moving west
      CGPoint corner = CGPointMake(cornerPoint.x + radius, currentPoint.y);
      [path LOT_addLineToPoint:corner];
      if (radius) {
        CGPoint curvePoint = clockwise ? CGPointMake(cornerPoint.x, cornerPoint.y - radius) : CGPointMake(cornerPoint.x, cornerPoint.y + radius);
        CGPoint cp1 = CGPointMake(corner.x - (radius * ellipseControlPointPercentage), corner.y);
        CGPoint cp2 = (clockwise ?
                       CGPointMake(curvePoint.x, curvePoint.y + (radius * ellipseControlPointPercentage)) :
                       CGPointMake(curvePoint.x, curvePoint.y - (radius * ellipseControlPointPercentage)));
        [path LOT_addCurveToPoint:curvePoint controlPoint1:cp1 controlPoint2:cp2];
      }
    } else {
      // Moving east
      CGPoint corner = CGPointMake(cornerPoint.x - radius, currentPoint.y);
      [path LOT_addLineToPoint:corner];
      if (radius) {
        CGPoint curvePoint = clockwise ? CGPointMake(cornerPoint.x, cornerPoint.y + radius) : CGPointMake(cornerPoint.x, cornerPoint.y - radius);
        CGPoint cp1 = CGPointMake(corner.x + (radius * ellipseControlPointPercentage), corner.y);
        CGPoint cp2 = (clockwise ?
                       CGPointMake(curvePoint.x, curvePoint.y - (radius * ellipseControlPointPercentage)) :
                       CGPointMake(curvePoint.x, curvePoint.y + (radius * ellipseControlPointPercentage)));
        [path LOT_addCurveToPoint:curvePoint controlPoint1:cp1 controlPoint2:cp2];
      }
    }
  } else {
    // Moving North/South
    if (cornerPoint.y < currentPoint.y) {
      // Moving North
      CGPoint corner = CGPointMake(currentPoint.x, cornerPoint.y + radius);
      [path LOT_addLineToPoint:corner];
      if (radius) {
        CGPoint curvePoint = clockwise ? CGPointMake(cornerPoint.x + radius, cornerPoint.y) : CGPointMake(cornerPoint.x - radius, cornerPoint.y);
        CGPoint cp1 = CGPointMake(corner.x, corner.y  - (radius * ellipseControlPointPercentage));
        CGPoint cp2 = (clockwise ?
                       CGPointMake(curvePoint.x - (radius * ellipseControlPointPercentage), curvePoint.y) :
                       CGPointMake(curvePoint.x + (radius * ellipseControlPointPercentage), curvePoint.y));
        [path LOT_addCurveToPoint:curvePoint controlPoint1:cp1 controlPoint2:cp2];
      }

    } else {
      // moving south
      CGPoint corner = CGPointMake(currentPoint.x, cornerPoint.y - radius);
      [path LOT_addLineToPoint:corner];
      if (radius) {
        CGPoint curvePoint = clockwise ? CGPointMake(cornerPoint.x - radius, cornerPoint.y) : CGPointMake(cornerPoint.x + radius, cornerPoint.y);
        CGPoint cp1 = CGPointMake(corner.x, corner.y  + (radius * ellipseControlPointPercentage));
        CGPoint cp2 = (clockwise ?
                       CGPointMake(curvePoint.x + (radius * ellipseControlPointPercentage), curvePoint.y) :
                       CGPointMake(curvePoint.x - (radius * ellipseControlPointPercentage), curvePoint.y));
        [path LOT_addCurveToPoint:curvePoint controlPoint1:cp1 controlPoint2:cp2];
      }
    }
  }
}

- (void)performLocalUpdate {
  CGFloat cornerRadius = [_cornerRadiusInterpolator floatValueForFrame:self.currentFrame];
  CGPoint size = [_sizeInterpolator pointValueForFrame:self.currentFrame];
  CGPoint position = [_centerInterpolator pointValueForFrame:self.currentFrame];
  
  CGFloat halfWidth = size.x / 2;
  CGFloat halfHeight = size.y / 2;
  
  CGRect rectFrame =  CGRectMake(position.x - halfWidth, position.y - halfHeight, size.x, size.y);
  
  CGPoint topLeft = CGPointMake(CGRectGetMinX(rectFrame), CGRectGetMinY(rectFrame));
  CGPoint topRight = CGPointMake(CGRectGetMaxX(rectFrame), CGRectGetMinY(rectFrame));
  CGPoint bottomLeft = CGPointMake(CGRectGetMinX(rectFrame), CGRectGetMaxY(rectFrame));
  CGPoint bottomRight = CGPointMake(CGRectGetMaxX(rectFrame), CGRectGetMaxY(rectFrame));
  // UIBezierPath Draws rects from the top left corner, After Effects draws them from the top right.
  // Switching to manual drawing.
  
  CGFloat radius = MIN(MIN(halfWidth, halfHeight), cornerRadius);
  BOOL clockWise = !_reversed;
  
  LOTBezierPath *path1 = [[LOTBezierPath alloc] init];
  path1.cacheLengths = self.pathShouldCacheLengths;
  CGPoint startPoint = (clockWise ?
                        CGPointMake(topRight.x, topRight.y + radius) :
                        CGPointMake(topRight.x - radius, topRight.y));
  [path1 LOT_moveToPoint:startPoint];
  if (clockWise) {
    [self addCorner:bottomRight withRadius:radius toPath:path1 clockwise:clockWise];
    [self addCorner:bottomLeft withRadius:radius toPath:path1 clockwise:clockWise];
    [self addCorner:topLeft withRadius:radius toPath:path1 clockwise:clockWise];
    [self addCorner:topRight withRadius:radius toPath:path1 clockwise:clockWise];
  } else {
    [self addCorner:topLeft withRadius:radius toPath:path1 clockwise:clockWise];
    [self addCorner:bottomLeft withRadius:radius toPath:path1 clockwise:clockWise];
    [self addCorner:bottomRight withRadius:radius toPath:path1 clockwise:clockWise];
    [self addCorner:topRight withRadius:radius toPath:path1 clockwise:clockWise];
  }
  [path1 LOT_closePath];
  self.localPath = path1;
}



@end