Files
leanote-ios/Leanote/editor/EditorClasses/CYRLayoutManager.m
2015-08-21 23:49:41 +08:00

229 lines
10 KiB
Objective-C
Executable File

//
// CYRLayoutManager.h
//
// Version 0.2.0
//
// Created by Illya Busigin on 01/05/2014.
// Copyright (c) 2014 Cyrillian, Inc.
//
// Distributed under MIT license.
// Get the latest version from here:
//
// https://github.com/illyabusigin/CYRTextView
// Original implementation taken from: https://github.com/alldritt/TextKit_LineNumbers
//
// The MIT License (MIT)
//
// Copyright (c) 2014 Cyrillian, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#import "CYRLayoutManager.h"
static CGFloat kMinimumGutterWidth = 30.f;
@interface CYRLayoutManager ()
@property (nonatomic, assign) CGFloat gutterWidth;
@property (nonatomic, assign) UIEdgeInsets lineAreaInset;
@property (nonatomic) NSUInteger lastParaLocation;
@property (nonatomic) NSUInteger lastParaNumber;
@end
@implementation CYRLayoutManager
#pragma mark - Initialization & Setup
- (instancetype)init
{
self = [super init];
if (self)
{
[self _commonSetup];
}
return self;
}
- (instancetype)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self)
{
[self _commonSetup];
}
return self;
}
- (void)_commonSetup
{
self.gutterWidth = kMinimumGutterWidth;
self.selectedRange = NSMakeRange(0, 0);
self.lineAreaInset = UIEdgeInsetsMake(0, 10, 0, 4);
self.lineNumberColor = [UIColor grayColor];
self.lineNumberFont = [UIFont systemFontOfSize:10.0f];
}
#pragma mark - Convenience
- (CGRect)paragraphRectForRange:(NSRange)range
{
range = [self.textStorage.string paragraphRangeForRange:range];
range = [self glyphRangeForCharacterRange:range actualCharacterRange:NULL];
CGRect startRect = [self lineFragmentRectForGlyphAtIndex:range.location effectiveRange:NULL];
CGRect endRect = [self lineFragmentRectForGlyphAtIndex:range.location + range.length - 1 effectiveRange:NULL];
CGRect paragraphRectForRange = CGRectUnion(startRect, endRect);
paragraphRectForRange = CGRectOffset(paragraphRectForRange, _gutterWidth, 8);
return paragraphRectForRange;
}
- (NSUInteger) _paraNumberForRange:(NSRange) charRange
{
// NSString does not provide a means of efficiently determining the paragraph number of a range of text. This code
// attempts to optimize what would normally be a series linear searches by keeping track of the last paragraph number
// found and uses that as the starting point for next paragraph number search. This works (mostly) because we
// are generally asked for continguous increasing sequences of paragraph numbers. Also, this code is called in the
// course of drawing a pagefull of text, and so even when moving back, the number of paragraphs to search for is
// relativly low, even in really long bodies of text.
//
// This all falls down when the user edits the text, and can potentially invalidate the cached paragraph number which
// causes a (potentially lengthy) search from the beginning of the string.
if (charRange.location == self.lastParaLocation)
return self.lastParaNumber;
else if (charRange.location < self.lastParaLocation)
{
// We need to look backwards from the last known paragraph for the new paragraph range. This generally happens
// when the text in the UITextView scrolls downward, revaling paragraphs before/above the ones previously drawn.
NSString* s = self.textStorage.string;
__block NSUInteger paraNumber = self.lastParaNumber;
[s enumerateSubstringsInRange:NSMakeRange(charRange.location, self.lastParaLocation - charRange.location)
options:NSStringEnumerationByParagraphs |
NSStringEnumerationSubstringNotRequired |
NSStringEnumerationReverse
usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop){
if (enclosingRange.location <= charRange.location) {
*stop = YES;
}
--paraNumber;
}];
self.lastParaLocation = charRange.location;
self.lastParaNumber = paraNumber;
return paraNumber;
}
else
{
// We need to look forward from the last known paragraph for the new paragraph range. This generally happens
// when the text in the UITextView scrolls upwards, revealing paragraphs that follow the ones previously drawn.
NSString* s = self.textStorage.string;
__block NSUInteger paraNumber = self.lastParaNumber;
[s enumerateSubstringsInRange:NSMakeRange(self.lastParaLocation, charRange.location - self.lastParaLocation)
options:NSStringEnumerationByParagraphs | NSStringEnumerationSubstringNotRequired
usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop){
if (enclosingRange.location >= charRange.location) {
*stop = YES;
}
++paraNumber;
}];
self.lastParaLocation = charRange.location;
self.lastParaNumber = paraNumber;
return paraNumber;
}
}
#pragma mark - Layouting
- (void)processEditingForTextStorage:(NSTextStorage *)textStorage edited:(NSTextStorageEditActions)editMask range:(NSRange)newCharRange changeInLength:(NSInteger)delta invalidatedRange:(NSRange)invalidatedCharRange
{
[super processEditingForTextStorage:textStorage edited:editMask range:newCharRange changeInLength:delta invalidatedRange:invalidatedCharRange];
if (invalidatedCharRange.location < self.lastParaLocation)
{
// When the backing store is edited ahead the cached paragraph location, invalidate the cache and force a complete
// recalculation. We cannot be much smarter than this because we don't know how many paragraphs have been deleted
// since the text has already been removed from the backing store.
self.lastParaLocation = 0;
self.lastParaNumber = 0;
}
}
#pragma mark - Drawing
- (void) drawBackgroundForGlyphRange:(NSRange)glyphsToShow atPoint:(CGPoint)origin
{
if (!self.shouldCompletelyHideGutter)
{
[super drawBackgroundForGlyphRange:glyphsToShow atPoint:origin];
// Draw line numbers. Note that the background for line number gutter is drawn by the LineNumberTextView class.
NSDictionary* atts = @{NSFontAttributeName : _lineNumberFont ,
NSForegroundColorAttributeName : _lineNumberColor};
[self enumerateLineFragmentsForGlyphRange:glyphsToShow
usingBlock:^(CGRect rect, CGRect usedRect, NSTextContainer *textContainer, NSRange glyphRange, BOOL *stop) {
NSRange charRange = [self characterRangeForGlyphRange:glyphRange actualGlyphRange:nil];
NSRange paraRange = [self.textStorage.string paragraphRangeForRange:charRange];
BOOL showCursorRect = NSLocationInRange(_selectedRange.location, paraRange);
if (showCursorRect)
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect cursorRect = CGRectMake(0, usedRect.origin.y + 8, _gutterWidth, usedRect.size.height);
CGContextSetFillColorWithColor(context, [UIColor colorWithWhite:0.9 alpha:1].CGColor);
CGContextFillRect(context, cursorRect);
}
// Only draw line numbers for the paragraph's first line fragment. Subsequent fragments are wrapped portions of the paragraph and don't get the line number.
if (charRange.location == paraRange.location) {
CGRect gutterRect = CGRectOffset(CGRectMake(0, rect.origin.y, _gutterWidth, rect.size.height), origin.x, origin.y);
NSUInteger paraNumber = [self _paraNumberForRange:charRange];
NSString* ln = [NSString stringWithFormat:@"%ld", (unsigned long) paraNumber + 1];
CGSize size = [ln sizeWithAttributes:atts];
[ln drawInRect:CGRectOffset(gutterRect, CGRectGetWidth(gutterRect) - _lineAreaInset.right - size.width - _gutterWidth, (CGRectGetHeight(gutterRect) - size.height) / 2.0)
withAttributes:atts];
}
}];
}
}
@end