mirror of
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232 lines
8.5 KiB
Objective-C
232 lines
8.5 KiB
Objective-C
/**
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* Copyright (c) 2015-present, Horcrux.
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* All rights reserved.
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*
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* This source code is licensed under the MIT-style license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#import "RNSVGTextPath.h"
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#import "RNSVGBezierElement.h"
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/* Some Bezier logic from PerformanceBezier */
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/*
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## License
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<a rel="license" href="http://creativecommons.org/licenses/by/3.0/us/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/3.0/us/88x31.png" /></a><br />This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/3.0/us/">Creative Commons Attribution 3.0 United States License</a>.
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For attribution, please include:
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1. Mention original author "Adam Wulf for Loose Leaf app"
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2. Link to https://getlooseleaf.com/opensource/
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3. Link to https://github.com/adamwulf/PerformanceBezier
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*/
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static CGFloat idealFlatness = .01;
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/**
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* returns the distance between two points
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*/
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CGFloat RNSVGPerformanceBezier_distance(CGPoint p1, CGPoint p2)
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{
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CGFloat dx = p2.x - p1.x;
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CGFloat dy = p2.y - p1.y;
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return hypot(dx, dy);
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}
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// Subdivide a Bézier (specific division)
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/*
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* (c) 2004 Alastair J. Houghton
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* All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. The name of the author of this software may not be used to endorse
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* or promote products derived from the software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE COPYRIGHT OWNER BE LIABLE FOR ANY DIRECT, INDIRECT,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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void RNSVGPerformanceBezier_subdivideBezierAtT(const CGPoint bez[4], CGPoint bez1[4], CGPoint bez2[4], CGFloat t)
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{
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CGPoint q;
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CGFloat mt = 1 - t;
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bez1[0].x = bez[0].x;
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bez1[0].y = bez[0].y;
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bez2[3].x = bez[3].x;
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bez2[3].y = bez[3].y;
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q.x = mt * bez[1].x + t * bez[2].x;
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q.y = mt * bez[1].y + t * bez[2].y;
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bez1[1].x = mt * bez[0].x + t * bez[1].x;
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bez1[1].y = mt * bez[0].y + t * bez[1].y;
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bez2[2].x = mt * bez[2].x + t * bez[3].x;
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bez2[2].y = mt * bez[2].y + t * bez[3].y;
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bez1[2].x = mt * bez1[1].x + t * q.x;
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bez1[2].y = mt * bez1[1].y + t * q.y;
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bez2[1].x = mt * q.x + t * bez2[2].x;
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bez2[1].y = mt * q.y + t * bez2[2].y;
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bez1[3].x = bez2[0].x = mt * bez1[2].x + t * bez2[1].x;
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bez1[3].y = bez2[0].y = mt * bez1[2].y + t * bez2[1].y;
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}
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void RNSVGPerformanceBezier_addLine(CGPoint *last, const CGPoint *next, NSMutableArray *lines, CGFloat *length, NSMutableArray *lengths) {
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NSArray *line = @[[NSValue valueWithCGPoint:*last], [NSValue valueWithCGPoint:*next]];
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[lines addObject:line];
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*length += RNSVGPerformanceBezier_distance(*last, *next);
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[lengths addObject:[NSNumber numberWithDouble:*length]];
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*last = *next;
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}
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@implementation RNSVGTextPath
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{
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CGPathRef _path;
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NSMutableArray *lengths;
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NSMutableArray *lines;
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NSUInteger lineCount;
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CGFloat length;
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BOOL isClosed;
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}
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- (void)getPathLength:(CGFloat*)lengthP lineCount:(NSUInteger*)lineCountP lengths:(NSArray* __strong *)lengthsP lines:(NSArray* __strong *)linesP isClosed:(BOOL*)isClosedP
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{
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RNSVGNode *template = [self.svgView getDefinedTemplate:self.href];
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CGPathRef path = [template getPath:nil];
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if (_path != path) {
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_path = path;
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CGPoint origin = CGPointMake (0.0, 0.0);
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CGPoint last = CGPointMake (0.0, 0.0);
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lengths = [NSMutableArray array];
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lines = [NSMutableArray array];
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isClosed = NO;
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lineCount = 0;
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length = 0;
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NSArray *elements = [RNSVGBezierElement elementsFromCGPath:path];
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for (RNSVGBezierElement *element in elements) {
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switch (element.elementType)
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{
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case kCGPathElementMoveToPoint:
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origin = last = element.point;
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break;
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case kCGPathElementAddLineToPoint: {
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CGPoint next = element.point;
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RNSVGPerformanceBezier_addLine(&last, &next, lines, &length, lengths);
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lineCount++;
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break;
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}
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case kCGPathElementAddQuadCurveToPoint:
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case kCGPathElementAddCurveToPoint:
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{
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// handle both curve types gracefully
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CGPoint curveTo = element.point;
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CGPoint ctrl1 = element.controlPoint1;
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CGPoint ctrl2 = element.elementType == kCGPathElementAddQuadCurveToPoint ? ctrl1 : element.controlPoint2;
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// this is the bezier for our current element
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CGPoint bezier[4] = { last, ctrl1, ctrl2, curveTo };
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NSValue *arr = [NSValue valueWithBytes:&bezier objCType:@encode(CGPoint[4])];
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NSMutableArray *curves = [NSMutableArray arrayWithObjects:arr, nil];
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for (NSInteger curveIndex = 0; curveIndex >= 0; curveIndex--) {
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CGPoint bez[4];
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[curves[curveIndex] getValue:&bez];
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[curves removeLastObject];
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// calculate the error rate of the curve vs
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// a line segment between the start and end points
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CGPoint ctrl1 = bez[1];
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CGPoint ctrl2 = bez[2];
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CGPoint next = bez[3];
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CGFloat polyLen =
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RNSVGPerformanceBezier_distance(last, ctrl1) +
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RNSVGPerformanceBezier_distance(ctrl1, ctrl2) +
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RNSVGPerformanceBezier_distance(ctrl2, next);
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CGFloat chordLen = RNSVGPerformanceBezier_distance(last, next);
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CGFloat error = polyLen - chordLen;
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// if the error is less than our accepted level of error
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// then add a line, else, split the curve in half
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if (error <= idealFlatness) {
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RNSVGPerformanceBezier_addLine(&last, &next, lines, &length, lengths);
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lineCount++;
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} else {
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CGPoint bez1[4], bez2[4];
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RNSVGPerformanceBezier_subdivideBezierAtT(bez, bez1, bez2, .5);
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[curves addObject:[NSValue valueWithBytes:&bez2 objCType:@encode(CGPoint[4])]];
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[curves addObject:[NSValue valueWithBytes:&bez1 objCType:@encode(CGPoint[4])]];
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curveIndex += 2;
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}
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}
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break;
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}
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case kCGPathElementCloseSubpath: {
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CGPoint next = origin;
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RNSVGPerformanceBezier_addLine(&last, &next, lines, &length, lengths);
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lineCount++;
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isClosed = YES;
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break;
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}
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default:
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break;
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}
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}
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}
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*lineCountP = lineCount;
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*isClosedP = isClosed;
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*lengthsP = lengths;
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*lengthP = length;
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*linesP = lines;
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}
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- (void)renderLayerTo:(CGContextRef)context rect:(CGRect)rect
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{
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[self renderGroupTo:context rect:rect];
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}
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- (CGPathRef)getPath:(CGContextRef)context
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{
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return [self getGroupPath:context];
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}
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- (void)pushGlyphContext
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{
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// TextPath do not affect the glyphContext
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}
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- (void)popGlyphContext
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{
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// TextPath do not affect the glyphContext
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}
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@end
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