iOS-CoreText的那些事【电子书的那些事】

这段时间在搞电子书，把这些天出现的问题归总下，我还是希望电子书的格式包括返回的数据，可直观的反应出客户端想表达的内容；原生的体验还是比较好的，希望对coretext再深入。

1.判断点击的位置是否在某个NSRange范围内

#pragma mark 判断点击的位置是否在 range内
/** 将点击的位置转换成字符串的偏移量，如果没有找到，则返回-1 view：view point：点击位置 frameRef：当前view的frameRef */
+ (CFIndex)wkj_touchContentOffsetInView:(UIView *)view point:(CGPoint)point frameRef:(CTFrameRef)frameRef{ CTFrameRef textFrame = frameRef; CFArrayRef lines = CTFrameGetLines(textFrame); if (!lines) { return -1; } CFIndex count = CFArrayGetCount(lines); // 获得每一行的origin坐标
 CGPoint origins[count]; CTFrameGetLineOrigins(textFrame, CFRangeMake(0,0), origins); // 翻转坐标系
    CGAffineTransform transform =  CGAffineTransformMakeTranslation(0, view.bounds.size.height); transform = CGAffineTransformScale(transform, 1.f, -1.f); CFIndex idx = -1; for (int i = 0; i < count; i++) { CGPoint linePoint = origins[i]; CTLineRef line = CFArrayGetValueAtIndex(lines, i); // 获得每一行的CGRect信息
        CGRect flippedRect = [self wkj_getLineBounds:line point:linePoint]; CGRect rect = CGRectApplyAffineTransform(flippedRect, transform); if (CGRectContainsPoint(rect, point)) { // 将点击的坐标转换成相对于当前行的坐标cocoapods
            CGPoint relativePoint = CGPointMake(point.x-CGRectGetMinX(rect), point.y-CGRectGetMinY(rect)); // 获得当前点击坐标对应的字符串偏移
            idx = CTLineGetStringIndexForPosition(line, relativePoint); } } return idx; } + (CGRect)wkj_getLineBounds:(CTLineRef)line point:(CGPoint)point { CGFloat ascent = 0.0f; CGFloat descent = 0.0f; CGFloat leading = 0.0f; CGFloat width = (CGFloat)CTLineGetTypographicBounds(line, &ascent, &descent, &leading); CGFloat height = ascent + descent; return CGRectMake(point.x, point.y - descent, width, height); } /** 此处判断 根据上面返回的字符串的偏移量，对比range是否在点击的位置 */
+ (BOOL)wkj_judgeAtIndex:(CFIndex)index range:(NSRange)range { if (NSLocationInRange(index, range)) { ///点击处在range内
        return YES; } return NO; }

 

 

2.通过CFRange与CTFrameRef获取要操作（涂色，划线）的CGRect数组

#pragma mark 通过range获取rect集合【用于划线、涂色】
+ (NSArray*)wkj_frameGetFrameOfStringInRange:(CTFrameRef)frameRef range:(CFRange)range{ CFRange frameRefRange = CTFrameGetStringRange(frameRef); range = [self wkj_cfRangeInsection:frameRefRange range:range]; if ([self wkj_cfRangeEqualToRange:range range:CFRangeZero]) { return nil; } NSArray *lines = (NSArray*)CTFrameGetLines(frameRef); NSInteger lineCount = [lines count]; //获取整个CTFrame的大小
    CGPathRef path = CTFrameGetPath(frameRef); CGRect frameRefRect = CGPathGetBoundingBox(path); //获取所有行的起点
    CGPoint *origins = (CGPoint*)malloc(lineCount * sizeof(CGPoint)); CTFrameGetLineOrigins(frameRef, CFRangeMake(0, 0), origins); NSMutableArray *rects = [NSMutableArray array]; for (CFIndex index = 0; index<lines.count; index++) { CTLineRef line = (__bridge CTLineRef)[lines objectAtIndex:index]; CFRange rangeOfLine = CTLineGetStringRange(line); CFRange rangeOfInsection = [self wkj_cfRangeInsection:rangeOfLine range:range]; if (![self wkj_cfRangeEqualToRange:rangeOfInsection range:CFRangeZero]) { CGRect frame = [self wkj_lineGetFrame:line point:origins[index] range:rangeOfInsection]; frame = CGRectOffset(frame, frameRefRect.origin.x, frameRefRect.origin.y); [rects addObject:[NSValue valueWithCGRect:frame]]; } } free(origins); return [rects copy]; } + (CGRect)wkj_lineGetFrame:(CTLineRef)line point:(CGPoint)origin range:(CFRange)range{ CFRange lineRange = CTLineGetStringRange(line); range = [self wkj_cfRangeInsection:lineRange range:range]; CGFloat trailingWhitespaceWidth = CTLineGetTrailingWhitespaceWidth(line); if ([self wkj_cfRangeGetEndLocation:range]==[self wkj_cfRangeGetEndLocation:lineRange]&&trailingWhitespaceWidth>0) { --range.length; } CGFloat xStart = CTLineGetOffsetForStringIndex(line, range.location, NULL); CGFloat xEnd = CTLineGetOffsetForStringIndex(line, [self wkj_cfRangeGetEndLocation:range]+1, NULL); CGFloat ascent, descent, leading; CTLineGetTypographicBounds(line, &ascent, &descent, &leading); CGRect selectionRect = CGRectMake(origin.x + xStart, origin.y - descent, xEnd - xStart, ascent + descent + leading); return selectionRect; } + (CFRange)wkj_cfRangeInsection:(CFRange)range1 range:(CFRange)range2{ if ([self wkj_cfRangeGreaterThanRange:range1 range:range2]||[self wkj_cfRangeGreaterThanRange:range2 range:range1]) { return CFRangeZero; } CFIndex beginLocation = MAX(range1.location, range2.location); CFIndex endLocation = MIN([self wkj_cfRangeGetEndLocation:range1], [self wkj_cfRangeGetEndLocation:range2]); return [self wkj_cfRangeMakeWithInterval:beginLocation endIndex:endLocation]; } + (BOOL)wkj_cfRangeGreaterThanRange:(CFRange)range1 range:(CFRange)range2{ return range1.location>[self wkj_cfRangeGetEndLocation:range2]; } + (CFIndex)wkj_cfRangeGetEndLocation:(CFRange)range{ return range.location+range.length-1; } + (CFRange)wkj_cfRangeMakeWithInterval:(CFIndex)startIndex endIndex:(CFIndex)endIndex{ return CFRangeMake(startIndex, endIndex - startIndex + 1); } + (BOOL)wkj_cfRangeEqualToRange:(CFRange)range1 range:(CFRange)range2{ return range1.location == range2.location&&range1.length==range2.length; }

 3.涂色划线

- (void)wkj_drawLineForSelectArea{ CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [[UIColor redColor] colorWithAlphaComponent:0.3].CGColor); for (NSValue *rectValue in _arraySelectRect) { CGRect rect = [rectValue CGRectValue]; rect.origin.y -= 2.5; ///划线时可设置高度为1 涂色是可根据字体大小设置
        rect.size.height = 1; rect.size.width -= 1.5; CGContextFillRect(context, rect); } }

 4.CoreText 分页

#pragma mark 分页
/** CoreText 分页 str: NSAttributedString属性字符串 textFrame: 绘制区域 */

+ (NSArray *)wkj_coreTextPaging:(NSAttributedString *)str textArea:(CGRect)textFrame{ ///分页NSAttributedString结果
 // NSMutableArray *arrayPagingStr = [NSMutableArray array];
    ///分页NSRange结果
    NSMutableArray *arrayPagingRange = [NSMutableArray array]; CFAttributedStringRef cfStrRef = (__bridge CFAttributedStringRef)str; CTFramesetterRef framesetterRef = CTFramesetterCreateWithAttributedString(cfStrRef); CGPathRef path = CGPathCreateWithRect(textFrame, NULL); int textPos = 0; NSUInteger strLength = [str length]; while (textPos < strLength) { //设置路径
        CTFrameRef frame = CTFramesetterCreateFrame(framesetterRef, CFRangeMake(textPos, 0), path, NULL); CFRange frameRange = CTFrameGetVisibleStringRange(frame); NSRange range = NSMakeRange(frameRange.location, frameRange.length); [arrayPagingRange addObject:[NSValue valueWithRange:range]];  // [arrayPagingStr addObject:[str attributedSubstringFromRange:range]]; //移动
        textPos += frameRange.length; CFRelease(frame); } CGPathRelease(path); CFRelease(framesetterRef);  // return arrayPagingStr;
    return arrayPagingRange; }

 5.获取绘制区域的高度

/**
 str:NSAttributedString 内容属性
 width: 绘制的宽度
 */
+ (CGFloat)coretextContentHeight:(NSAttributedString *)str width:(CGFloat)width{
    //创建CTFramesetterRef
    CTFramesetterRef framesetterRef = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)str);
    // 获得要绘制的区域高度
    CGSize restrictSize = CGSizeMake(width, CGFLOAT_MAX);
    CGSize coreTextSize = CTFramesetterSuggestFrameSizeWithConstraints(framesetterRef, CFRangeMake(0,0), nil, restrictSize, nil);
   return coreTextSize.height;
}

 

项目笔记

#import "BookDataTool.h"
#import "CoreTextDataModel.h"

@implementation BookDataTool

/**
 CoreText 分页
 str: NSAttributedString属性字符串
 textFrame: 绘制区域
 */

+ (NSArray *)wkj_coreTextPaging:(NSAttributedString *)str
                       textArea:(CGRect)textFrame{
//    textFrame.size.height = textFrame.size.height;
    
    ///分页NSAttributedString结果
    //    NSMutableArray *arrayPagingStr = [NSMutableArray array];
    ///分页NSRange结果
    NSMutableArray *arrayCoretext = [NSMutableArray array];
    
    CFAttributedStringRef cfStrRef = (__bridge CFAttributedStringRef)str;
    CTFramesetterRef framesetterRef = CTFramesetterCreateWithAttributedString(cfStrRef);
    CGPathRef path = CGPathCreateWithRect(textFrame, NULL);
    
    int textPos = 0;
    NSUInteger strLength = [str length];
    while (textPos < strLength)  {
        //设置路径
        CTFrameRef frame = CTFramesetterCreateFrame(framesetterRef, CFRangeMake(textPos, 0), path, NULL);
        CFRange frameRange = CTFrameGetVisibleStringRange(frame);
        NSRange range = NSMakeRange(frameRange.location, frameRange.length);
        
//        [arrayPagingRange addObject:[NSValue valueWithRange:range]];
        //        [arrayPagingStr addObject:[str attributedSubstringFromRange:range]];
        
        CoreTextDataModel *model = [[CoreTextDataModel alloc]init];
        model.ctFrame = frame;
        model.range = range;
        model.content = [str attributedSubstringFromRange:range];
        
        [arrayCoretext addObject:model];
        //移动
        textPos += frameRange.length;
        CFRelease(frame);
    }
    CGPathRelease(path);
    CFRelease(framesetterRef);
    //    return arrayPagingStr;
    return arrayCoretext;
}





///获取属性字符串
+ (NSAttributedString *)wkj_loadTemplateFile:(NSString *)path{
    NSMutableAttributedString *resultAtt = [[NSMutableAttributedString alloc] init];
    NSData *data = [NSData dataWithContentsOfFile:path];
    if (data) {
        NSArray *array = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
        if ([array isKindOfClass:[NSArray class]]) {
            for (NSDictionary *dic in array) {
                if ([dic[@"type"] isEqualToString:@"txt"]) {
                    NSAttributedString *att = [self parseAttributedContentFromDictionary:dic];
                    [resultAtt appendAttributedString:att];
                }
            }
        }
    }
    return resultAtt;
}
///获取属性字符串
+ (NSAttributedString *)parseAttributedContentFromDictionary:(NSDictionary *)dict{
    NSMutableDictionary *attributes = [self attributes];
    if ([dict[@"type1"] isEqualToString:@"0"]) {
        CTFontRef fontRef = CTFontCreateWithName((CFStringRef)@"ArialMT", 35, NULL);
        attributes[(id)kCTFontAttributeName] = (__bridge id)fontRef;
        CFRelease(fontRef);
    }
    NSString *content = dict[@"content"];
    return [[NSAttributedString alloc] initWithString:content attributes:attributes];
}
///获取属性字符串字典
+ (NSMutableDictionary *)attributes{
    CGFloat fontSize = [BookThemeManager sharedManager].fontSize;
    CTFontRef fontRef = CTFontCreateWithName((CFStringRef)@"ArialMT", fontSize, NULL);
    CGFloat lineSpacing = [BookThemeManager sharedManager].lineSpace;
    const CFIndex kNumberOfSettings = 3;
    CTParagraphStyleSetting theSettings[kNumberOfSettings] = {
        { kCTParagraphStyleSpecifierLineSpacingAdjustment, sizeof(CGFloat), &lineSpacing },
        { kCTParagraphStyleSpecifierMaximumLineSpacing, sizeof(CGFloat), &lineSpacing },
        { kCTParagraphStyleSpecifierMinimumLineSpacing, sizeof(CGFloat), &lineSpacing }
    };
    
    CTParagraphStyleRef theParagraphRef = CTParagraphStyleCreate(theSettings, kNumberOfSettings);
    
    UIColor * textColor = [BookThemeManager sharedManager].textColor;
    
    NSMutableDictionary * dict = [NSMutableDictionary dictionary];
    dict[(id)kCTForegroundColorAttributeName] = (id)textColor.CGColor;
    dict[(id)kCTFontAttributeName] = (__bridge id)fontRef;
    dict[(id)kCTParagraphStyleAttributeName] = (__bridge id)theParagraphRef;
    CFRelease(theParagraphRef);
    CFRelease(fontRef);
    return dict;
}

@end