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// NSString_CustomTruncation.m
// Notation
// Created by Zachary Schneirov on 1/12/11.
/*Copyright (c) 2010, Zachary Schneirov. All rights reserved.
This file is part of Notational Velocity.
Notational Velocity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Notational Velocity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Notational Velocity. If not, see <>. */
#import "NSString_CustomTruncation.h"
#import "GlobalPrefs.h"
@implementation NSString (CustomTruncation)
static NSMutableParagraphStyle *LineBreakingStyle();
static NSDictionary *GrayTextAttributes();
static NSDictionary *LineTruncAttributes();
static size_t EstimatedCharCountForWidth(float upToWidth);
- (NSString*)truncatedPreviewStringOfLength:(NSUInteger)bodyCharCount {
//try to get the underlying C-string buffer and copy only part of it
//this won't be exact because chars != bytes, but that's alright because it is expected to be further truncated by an NSTextFieldCell
CFStringEncoding bodyPreviewEncoding = CFStringGetFastestEncoding((CFStringRef)self);
const char * cStrPtr = CFStringGetCStringPtr((CFStringRef)self, bodyPreviewEncoding);
char *bodyPreviewBuffer = calloc(bodyCharCount + 1, sizeof(char));
CFIndex usedBufLen = bodyCharCount;
if (bodyCharCount > 1) {
if (cStrPtr && kCFStringEncodingUTF8 != bodyPreviewEncoding && kCFStringEncodingUnicode != bodyPreviewEncoding) {
//only attempt to copy the buffer directly if the fastest encoding is not a unicode variant
memcpy(bodyPreviewBuffer, cStrPtr, bodyCharCount);
} else {
bodyPreviewEncoding = kCFStringEncodingUTF8;
if ([self length] == bodyCharCount) {
//if this is supposed to be the entire string, don't waffle around
const char *fullUTF8String = [self UTF8String];
if (fullUTF8String) {
usedBufLen = bodyCharCount = strlen(fullUTF8String);
bodyPreviewBuffer = realloc(bodyPreviewBuffer, bodyCharCount + 1);
memcpy(bodyPreviewBuffer, fullUTF8String, bodyCharCount + 1);
goto replace;
if (!CFStringGetBytes((CFStringRef)self, CFRangeMake(0, bodyCharCount), bodyPreviewEncoding, ' ', FALSE,
(UInt8 *)bodyPreviewBuffer, bodyCharCount + 1, &usedBufLen)) {
NSLog(@"can't get utf8 string from '%@' (charcount: %u)", self, bodyCharCount);
return nil;
//if bodyPreviewBuffer is a UTF-8 encoded string, then examine the string one UTF-8 sequence at a time to catch multi-byte breaks
if (bodyPreviewEncoding == kCFStringEncodingUTF8) {
replace_breaks_utf8(bodyPreviewBuffer, bodyCharCount);
} else {
replace_breaks(bodyPreviewBuffer, bodyCharCount);
NSString* truncatedBodyString = [[NSString alloc] initWithBytesNoCopy:bodyPreviewBuffer length:usedBufLen
encoding:CFStringConvertEncodingToNSStringEncoding(bodyPreviewEncoding) freeWhenDone:YES];
if (!truncatedBodyString) {
NSLog(@"can't create cfstring from '%@' (cstr lens: %u/%d) with encoding %u (fastest = %u)", self, bodyCharCount, usedBufLen, bodyPreviewEncoding, CFStringGetFastestEncoding((CFStringRef)self));
return nil;
return [truncatedBodyString autorelease];
static NSMutableDictionary *titleTruncAttrs = nil;
void ResetFontRelatedTableAttributes() {
[titleTruncAttrs release];
titleTruncAttrs = nil;
static NSMutableParagraphStyle *LineBreakingStyle() {
static NSMutableParagraphStyle *lineBreaksStyle = nil;
if (!lineBreaksStyle) {
lineBreaksStyle = [[NSMutableParagraphStyle alloc] init];
[lineBreaksStyle setLineBreakMode:NSLineBreakByTruncatingTail];
[lineBreaksStyle setTighteningFactorForTruncation:0.0];
return lineBreaksStyle;
static NSDictionary *GrayTextAttributes() {
static NSDictionary *grayTextAttributes = nil;
if (!grayTextAttributes) grayTextAttributes = [[NSDictionary dictionaryWithObjectsAndKeys:[NSColor grayColor], NSForegroundColorAttributeName, nil] retain];
return grayTextAttributes;
static NSDictionary *LineTruncAttributes() {
static NSDictionary *lineTruncAttributes = nil;
if (!lineTruncAttributes) lineTruncAttributes = [[NSDictionary dictionaryWithObjectsAndKeys:LineBreakingStyle(), NSParagraphStyleAttributeName, nil] retain];
return lineTruncAttributes;
NSDictionary *LineTruncAttributesForTitle() {
if (!titleTruncAttrs) {
GlobalPrefs *prefs = [GlobalPrefs defaultPrefs];
unsigned int bitmap = [prefs tableColumnsBitmap];
float fontSize = [prefs tableFontSize];
BOOL usesBold = ColumnIsSet(NoteLabelsColumn, bitmap) || ColumnIsSet(NoteDateCreatedColumn, bitmap) ||
ColumnIsSet(NoteDateModifiedColumn, bitmap) || [prefs tableColumnsShowPreview];
titleTruncAttrs = [[NSDictionary dictionaryWithObjectsAndKeys:[[LineBreakingStyle() mutableCopy] autorelease], NSParagraphStyleAttributeName,
(usesBold ? [NSFont boldSystemFontOfSize:fontSize] : [NSFont systemFontOfSize:fontSize]), NSFontAttributeName, nil] retain];
if (ColumnIsSet(NoteDateCreatedColumn, bitmap) || ColumnIsSet(NoteDateModifiedColumn, bitmap)) {
//account for right-"aligned" date string, which will be relatively constant, so this can be cached
[[titleTruncAttrs objectForKey:NSParagraphStyleAttributeName] setTailIndent: fontSize * -4.6]; //avg of -55 for ~11-12 font size
return titleTruncAttrs;
static size_t EstimatedCharCountForWidth(float upToWidth) {
return (size_t)(upToWidth / ([[GlobalPrefs defaultPrefs] tableFontSize] / 2.5f));
//LineTruncAttributesForTags would be variable, depending on the note; each preview string will have its own copy of the nsdictionary
- (NSAttributedString*)attributedMultiLinePreviewFromBodyText:(NSAttributedString*)bodyText upToWidth:(float)upToWidth intrusionWidth:(float)intWidth {
//first line is title, truncated to a shorter width to account for date/time, using a negative -[NSMutableParagraphStyle setTailIndent:] value
//next "two" lines are wrapped body text, with a character-count estimation of essentially double that of a single-line preview
//also with an independent tailindent to account for a separately-drawn tags-string, if tags exist
//upToWidth will be used to manually truncate note-bodies only, and should be the full column width available
//intWidth will typically be the width of the tags string or other representation
size_t bodyCharCount = (EstimatedCharCountForWidth(upToWidth) * 2) - EstimatedCharCountForWidth(intWidth);
bodyCharCount = MIN(bodyCharCount, [bodyText length]);
NSMutableString *unattributedPreview = [[NSMutableString alloc] initWithCapacity:bodyCharCount + [self length] + 2];
NSString *truncatedBodyString = [[bodyText string] truncatedPreviewStringOfLength:bodyCharCount];
if (!truncatedBodyString) return nil;
[unattributedPreview appendString:self];
[unattributedPreview appendString:@"\n"];
[unattributedPreview appendString:truncatedBodyString];
NSMutableAttributedString *attributedStringPreview = [[NSMutableAttributedString alloc] initWithString:unattributedPreview];
//title is black (no added colors) and truncated with LineTruncAttributesForTitle()
//body is gray and truncated with a variable tail indent, depending on intruding tags
NSDictionary *bodyTruncDict = [NSDictionary dictionaryWithObjectsAndKeys:[[LineBreakingStyle() mutableCopy] autorelease],
NSParagraphStyleAttributeName, [NSColor grayColor], NSForegroundColorAttributeName, nil];
//set word-wrapping to let -[NSCell setTruncatesLastVisibleLine:] work
[[bodyTruncDict objectForKey:NSParagraphStyleAttributeName] setLineBreakMode:NSLineBreakByWordWrapping];
if (intWidth > 0.0) {
//there are tags; add an appropriately-sized tail indent to the body
[[bodyTruncDict objectForKey:NSParagraphStyleAttributeName] setTailIndent:-intWidth];
[attributedStringPreview addAttributes:LineTruncAttributesForTitle() range:NSMakeRange(0, [self length])];
[attributedStringPreview addAttributes:bodyTruncDict range:NSMakeRange([self length] + 1, [unattributedPreview length] - ([self length] + 1))];
[unattributedPreview release];
return [attributedStringPreview autorelease];
- (NSAttributedString*)attributedSingleLineTitle {
//show only a single line, with a tail indent large enough for both the date and tags (if there are any)
//because this method displays the title only, manual truncation isn't really necessary
//the highlighted version of this string should be bolded
NSMutableAttributedString *titleStr = [[NSMutableAttributedString alloc] initWithString:self attributes:LineTruncAttributesForTitle()];
return [titleStr autorelease];
- (NSAttributedString*)attributedSingleLinePreviewFromBodyText:(NSAttributedString*)bodyText upToWidth:(float)upToWidth {
//compute the char count for this note based on the width of the title column and the length of the receiver
size_t bodyCharCount = EstimatedCharCountForWidth(upToWidth) - [self length];
bodyCharCount = MIN(bodyCharCount, [bodyText length]);
NSString *truncatedBodyString = [[bodyText string] truncatedPreviewStringOfLength:bodyCharCount];
if (!truncatedBodyString) return nil;
NSMutableString *unattributedPreview = [self mutableCopy];
NSString *delimiter = NSLocalizedString(@" option-shift-dash ", @"title/description delimiter");
[unattributedPreview appendString:delimiter];
[unattributedPreview appendString:truncatedBodyString];
NSMutableAttributedString *attributedStringPreview = [[NSMutableAttributedString alloc] initWithString:unattributedPreview attributes:LineTruncAttributes()];
[attributedStringPreview addAttributes:GrayTextAttributes() range:NSMakeRange([self length], [unattributedPreview length] - [self length])];
[unattributedPreview release];
return [attributedStringPreview autorelease];