Curtis Hard
111 lines
4.9 KiB
Objective-C
111 lines
4.9 KiB
Objective-C
//
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// IJSVGCommandArc.m
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// IJSVGExample
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//
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// Created by Curtis Hard on 03/09/2014.
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// Copyright (c) 2014 Curtis Hard. All rights reserved.
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//
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#import "IJSVGCommandArc.h"
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#import "IJSVGUtils.h"
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@implementation IJSVGCommandArc
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+ (NSInteger)requiredParameterCount
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{
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return 7;
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}
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+ (void)runWithParams:(CGFloat *)params
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paramCount:(NSInteger)count
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command:(IJSVGCommand *)currentCommand
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previousCommand:(IJSVGCommand *)command
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type:(IJSVGCommandType)type
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path:(IJSVGPath *)path
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{
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CGPoint radii = CGPointZero;
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CGPoint arcEndPoint = CGPointZero;
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CGPoint arcStartPoint = path.currentPoint;
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CGFloat xAxisRotation = 0;
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BOOL largeArcFlag = 0;
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BOOL sweepFlag = 0;
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radii = [currentCommand readPoint];
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xAxisRotation = [currentCommand readFloat];
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largeArcFlag = [currentCommand readBOOL];
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sweepFlag = [currentCommand readBOOL];
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arcEndPoint = [currentCommand readPoint];
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if (type == IJSVGCommandTypeRelative) {
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arcEndPoint.x += path.currentPoint.x;
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arcEndPoint.y += path.currentPoint.y;
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}
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xAxisRotation *= M_PI / 180.f;
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CGPoint currentPoint = CGPointMake(cos(xAxisRotation) * (arcStartPoint.x - arcEndPoint.x) / 2.0 + sin(xAxisRotation) * (arcStartPoint.y - arcEndPoint.y) / 2.0, -sin(xAxisRotation) * (arcStartPoint.x - arcEndPoint.x) / 2.0 + cos(xAxisRotation) * (arcStartPoint.y - arcEndPoint.y) / 2.0);
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CGFloat radiiAdjustment = pow(currentPoint.x, 2) / pow(radii.x, 2) + pow(currentPoint.y, 2) / pow(radii.y, 2);
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radii.x *= (radiiAdjustment > 1) ? sqrt(radiiAdjustment) : 1;
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radii.y *= (radiiAdjustment > 1) ? sqrt(radiiAdjustment) : 1;
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CGFloat sweep = (largeArcFlag == sweepFlag ? -1 : 1) * sqrt(((pow(radii.x, 2) * pow(radii.y, 2)) - (pow(radii.x, 2) * pow(currentPoint.y, 2)) - (pow(radii.y, 2) * pow(currentPoint.x, 2))) / (pow(radii.x, 2) * pow(currentPoint.y, 2) + pow(radii.y, 2) * pow(currentPoint.x, 2)));
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sweep = (sweep != sweep) ? 0 : sweep;
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CGPoint preCenterPoint = CGPointMake(sweep * radii.x * currentPoint.y / radii.y, sweep * -radii.y * currentPoint.x / radii.x);
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CGPoint centerPoint = CGPointMake((arcStartPoint.x + arcEndPoint.x) / 2.0 + cos(xAxisRotation) * preCenterPoint.x - sin(xAxisRotation) * preCenterPoint.y, (arcStartPoint.y + arcEndPoint.y) / 2.0 + sin(xAxisRotation) * preCenterPoint.x + cos(xAxisRotation) * preCenterPoint.y);
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CGFloat startAngle = angle(CGPointMake(1, 0), CGPointMake((currentPoint.x-preCenterPoint.x)/radii.x,
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(currentPoint.y-preCenterPoint.y)/radii.y));
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CGPoint deltaU = CGPointMake((currentPoint.x - preCenterPoint.x) / radii.x,
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(currentPoint.y - preCenterPoint.y) / radii.y);
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CGPoint deltaV = CGPointMake((-currentPoint.x - preCenterPoint.x) / radii.x,
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(-currentPoint.y - preCenterPoint.y) / radii.y);
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CGFloat angleDelta = (deltaU.x * deltaV.y < deltaU.y * deltaV.x ? -1 : 1) * acos(ratio(deltaU, deltaV));
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angleDelta = (ratio(deltaU, deltaV) <= -1) ? M_PI : (ratio(deltaU, deltaV) >= 1) ? 0 : angleDelta;
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// check for actually numbers, if this is not valid
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// kill it, blame WWDC 2017 SVG background for this...
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if(isnan(startAngle) || isnan(angleDelta)) {
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return;
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}
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CGFloat radius = MAX(radii.x, radii.y);
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CGPoint scale = (radii.x > radii.y) ? CGPointMake(1, radii.y / radii.x) :
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CGPointMake(radii.x / radii.y, 1);
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NSAffineTransform * trans = [NSAffineTransform transform];
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[trans translateXBy:-centerPoint.x yBy:-centerPoint.y];
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[path.currentSubpath transformUsingAffineTransform:trans];
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trans = [NSAffineTransform transform];
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[trans rotateByRadians:-xAxisRotation];
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[path.currentSubpath transformUsingAffineTransform:trans];
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trans = [NSAffineTransform transform];
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[trans scaleXBy:(1/scale.x) yBy:(1/scale.y)];
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[path.currentSubpath transformUsingAffineTransform:trans];
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[path.currentSubpath appendBezierPathWithArcWithCenter:NSZeroPoint
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radius:radius
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startAngle:radians_to_degrees(startAngle)
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endAngle:radians_to_degrees(startAngle + angleDelta)
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clockwise:!sweepFlag];
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trans = [NSAffineTransform transform];
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[trans scaleXBy:scale.x yBy:scale.y];
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[path.currentSubpath transformUsingAffineTransform:trans];
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trans = [NSAffineTransform transform];
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[trans rotateByRadians:xAxisRotation];
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[path.currentSubpath transformUsingAffineTransform:trans];
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trans = [NSAffineTransform transform];
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[trans translateXBy:centerPoint.x yBy:centerPoint.y];
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[path.currentSubpath transformUsingAffineTransform:trans];
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}
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@end
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