The height of the weex <text> component is not accurate? - ios

The current WeexSDK version 0.18.0,I use show similar effect on the simulator and the real machine and the text can't be fully displayed as shown below.
Also I've added the script to show how to calculate the height of the text component in source code is done. suggestSize.heightis always the height I want, but this code is only executed under iOS10. The value of totalHeight is always worse when I have more text lines than iOS10. How do I solve this?
The effect is as follows:
The source code:
- (CGSize)calculateTextHeightWithWidth:(CGFloat)aWidth
{
CGFloat totalHeight = 0;
CGSize suggestSize = CGSizeZero;
NSAttributedString * attributedStringCpy = [self ctAttributedString];
if (!attributedStringCpy) {
return CGSizeZero;
}
if (isnan(aWidth)) {
aWidth = CGFLOAT_MAX;
}
aWidth = [attributedStringCpy boundingRectWithSize:CGSizeMake(aWidth, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading context:nil].size.width;
/* Must get ceil of aWidth. Or core text may not return correct bounds.
Maybe aWidth without ceiling triggered some critical conditions. */
aWidth = ceil(aWidth);
CTFramesetterRef ctframesetterRef = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)(attributedStringCpy));
suggestSize = CTFramesetterSuggestFrameSizeWithConstraints(ctframesetterRef, CFRangeMake(0, 0), NULL, CGSizeMake(aWidth, MAXFLOAT), NULL);
if (_lines == 0) {
// If not line limit use suggestSize directly.
CFRelease(ctframesetterRef);
return CGSizeMake(aWidth, suggestSize.height);
}
CGMutablePathRef path = NULL;
path = CGPathCreateMutable();
// sufficient height to draw text
CGPathAddRect(path, NULL, CGRectMake(0, 0, aWidth, suggestSize.height * 10));
CTFrameRef frameRef = NULL;
frameRef = CTFramesetterCreateFrame(ctframesetterRef, CFRangeMake(0, attributedStringCpy.length), path, NULL);
CGPathRelease(path);
CFRelease(ctframesetterRef);
if (NULL == frameRef) {
//try to protect unexpected crash.
return suggestSize;
}
CFArrayRef lines = CTFrameGetLines(frameRef);
CFIndex lineCount = CFArrayGetCount(lines);
CGFloat ascent = 0;
CGFloat descent = 0;
CGFloat leading = 0;
// height = ascent + descent + lineCount*leading
// ignore linespaing
NSUInteger actualLineCount = 0;
for (CFIndex lineIndex = 0; (!_lines|| lineIndex < _lines) && lineIndex < lineCount; lineIndex ++)
{
CTLineRef lineRef = NULL;
lineRef = (CTLineRef)CFArrayGetValueAtIndex(lines, lineIndex);
CTLineGetTypographicBounds(lineRef, &ascent, &descent, &leading);
totalHeight += ascent + descent;
actualLineCount ++;
}
totalHeight = totalHeight + actualLineCount * leading;
CFRelease(frameRef);
if (WX_SYS_VERSION_LESS_THAN(#"10.0")) {
// there is something wrong with coreText drawing text height, trying to fix this with more efficent way.
if(actualLineCount && actualLineCount < lineCount) {
suggestSize.height = suggestSize.height * actualLineCount / lineCount;
}
return CGSizeMake(aWidth, suggestSize.height);
}
return CGSizeMake(aWidth, totalHeight);
}

Related

How to truncate label in cocos2dV3.0

i am trying to truncate label when text becomes large but instead it got expanded from center moving to left side.
This is my snippet.
CCLabelTTF *playerLabel = [CCLabelTTF labelWithString:[NSString stringWithFormat:#"Playerdadsadsd %d",i+1] fontName:#"Helvetica-Bold" fontSize:fontSize];
playerLabel.color = playerColor;
playerLabel.name = [NSString stringWithFormat:#"%d",1002+i];
playerLabel.position = ccp(playerSprite.position.x + playerSprite.contentSize.width + 10, yPos);
playerLabel.adjustsFontSizeToFit = YES;
[self addChild:playerLabel];
I'm not sure what are you trying to achieve, but try passing dimensions parameter to the init method:
//The label won't go out of this rectangle
CGSize rect = CGSizeMake(viewSize.width * 0.1f, viewSize.height * 0.1f);
NSString *text = [NSString stringWithFormat:#"Playerdadsadsd %d",i+1];
CCLabelTTF *playerLabel = [CCLabelTTF labelWithString: text
fontName: #"Helvetica-Bold"
fontSize: fontSize
dimensions: rect]; // <-- Note this parameter
//.. the rest of your code..
I didn't find any intrinsic solution in cocos2d-x for truncating (with or without ellipsis) a label to fit in a specified width, so I wrote a function of my own.
This is in C++, but the logic can be copied easily to Objective-C
CCLabelTTF *createTruncatedLabel(const char *text, const char *fontFace, float fontSize, int width, bool useEllipsis)
{
CCLabelTTF *ttfLabel = CCLabelTTF::create(text, fontFace, fontSize, CCSizeMake(0, 0), kCCTextAlignmentLeft);
CCSize size = ttfLabel->getContentSize();
if (size.width > width)
{
int len = strlen(text);
float pc = (float)width / (float)size.width;
int newLen = (int)((float)len * pc);
size = setTruncLabel(ttfLabel, text, newLen, useEllipsis);
if (size.width > width)
{
while (size.width > width)
{
newLen--;
size = setTruncLabel(ttfLabel, text, newLen, useEllipsis);
}
}
else
{
while (size.width < width)
{
newLen++;
size = setTruncLabel(ttfLabel, text, newLen, useEllipsis);
}
if (size.width > width)
{
newLen--;
setTruncLabel(ttfLabel, text, newLen, useEllipsis);
}
}
}
return ttfLabel;
}
CCSize setTruncLabel(CCLabelTTF *ttfLabel, const char*text, int len, bool useEllipsis)
{
char newText[256] = {0};
strncpy(newText, text, len);
if (useEllipsis)
{
strcat(newText, "...");
}
ttfLabel->setString(newText);
CCSize size = ttfLabel->getContentSize();
return size;
}

Calculate Height from NSAttributedString with NSParagraphStyle

I want to calculate the height of a NSAttributedString with the NSParagraphStyle attribute.
I thought it will be easy to create a UILabel with higher spacing between the lines but i can't calculate the right height for my UITableViewCell.
I tried to calculate it with boundingRectWithSize:options: but it's not working at all…
I use NSLayoutManager's usedRectForTextContainer: with a TextView stack disconnected from a UITableView. I answered a similar Stack Overflow question and explained how to implement it.
When the convinient methods from apple dont work, this category provides a good aproximation in most cases.
#implementation NSAttributedString (PixLib)
- (CGFloat)heightForWidth:(CGFloat)width {
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectMake(0, 0, width, 99999));
CGFloat h = [self heightForPath:path];
CGPathRelease(path);
return h;
}
- (CGFloat)heightForPath:(CGPathRef)path {
CGFloat height = 0;
CTFrameRef frame = [self cfframeForPath:path];
if (frame != NULL) {
NSArray* lines = (__bridge NSArray*)CTFrameGetLines(frame);
int l = [lines count];
if (l > 1) {
CGPoint origins[l];
CTFrameGetLineOrigins(frame, CFRangeMake(0, l), origins);
CGFloat yFirst = origins[0].y;
CGFloat yLast = origins[l-1].y;
CGFloat ascent, descent, leading;
CTLineGetTypographicBounds((__bridge CTLineRef)[lines objectAtIndex:l-1], &ascent, &descent, &leading);
height = ceilf((ascent+descent+leading)*1.3) + yFirst-yLast;
} else {
if (l==1) {
CGFloat ascent, descent, leading;
CTLineGetTypographicBounds((__bridge CTLineRef)[lines objectAtIndex:0], &ascent, &descent, &leading);
height = ceilf(ascent+descent+leading)*1.3;
}
}
CFRelease(frame);
}
return height;
}
- (CTFrameRef)cfframeForPath:(CGPathRef)p {
// hack to avoid bugs width different behavior in iOS <4.3 and >4.3
CGMutablePathRef path = CGPathCreateMutable();
CGRect r = CGPathGetBoundingBox(p);
CGAffineTransform t = CGAffineTransformIdentity;
t = CGAffineTransformTranslate(t, r.origin.x, r.origin.y);
t = CGAffineTransformScale(t, 1, -1);
t = CGAffineTransformTranslate(t, r.origin.x, - ( r.origin.y + r.size.height ));
CGPathAddPath(path, &t, p);
CGPathMoveToPoint(path, NULL, 0, 0);
CGPathCloseSubpath(path);
// hack end
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)self);
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);
CFRelease(framesetter);
CGPathRelease(path);
return frame;
}
#end

CTFramesetterSuggestFrameSizeWithConstraints returns incorrect height when zoom out?

I'm work with EGOTextView.I set the textContentView for viewForZoomingInScrollView.when I zoom it out and typing.It sometimes returns a incorrect height. Here is what I am doing:
CTFramesetterRef framesetter = _framesetter;
CFAttributedStringRef attributedStringRef=(CFAttributedStringRef)self.attributedString;
_framesetter = CTFramesetterCreateWithAttributedString(attributedStringRef);
if (framesetter!=NULL) {
CFRelease(framesetter);
}
CGRect rect = self.textContextView.frame;
CGFloat height = [self heightForAttributedString:self.attributedString forWidth:rect.size.width];
rect.size.height = (height + self.font.lineHeight * 2) * pageScale;
//pageScale is the scale scrollview end zooming
- (CGFloat)boundingHeightForWidth:(CGFloat)width {
CGSize suggestedSize = CTFramesetterSuggestFrameSizeWithConstraints(_framesetter, CFRangeMake(0, 0), NULL, CGSizeMake(width , CGFLOAT_MAX), NULL);
return suggestedSize.height;
}
And I try this method too:
+(CGFloat)heightForAttributedString:(NSAttributedString *)attrString forWidth:(CGFloat)inWidth
{
CGFloat H = 0;
// Create the framesetter with the attributed string.
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString( (CFMutableAttributedStringRef) attrString);
CGRect box = CGRectMake(0,0, inWidth, CGFLOAT_MAX);
CFIndex startIndex = 0;
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, box);
// Create a frame for this column and draw it.
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(startIndex, 0), path, NULL);
// Start the next frame at the first character not visible in this frame.
//CFRange frameRange = CTFrameGetVisibleStringRange(frame);
//startIndex += frameRange.length;
CFArrayRef lineArray = CTFrameGetLines(frame);
CFIndex j = 0, lineCount = CFArrayGetCount(lineArray);
CGFloat h, ascent, descent, leading;
for (j=0; j < lineCount; j++)
{
CTLineRef currentLine = (CTLineRef)CFArrayGetValueAtIndex(lineArray, j);
CTLineGetTypographicBounds(currentLine, &ascent, &descent, &leading);
h = ascent + descent + leading;
NSLog(#"%f", h);
H+=h;
}
CFRelease(frame);
CFRelease(path);
CFRelease(framesetter);
return H;
}
But it seems always return a wrong height when you typing text after zoom.
Is there any other/better way to figure out the correct height for my attributed string? Thanks!
I also run in this case, solved it and wrote a category, which works for me in all cases. See my answer in If you use zero as height, it does not restrict the height to any height. I wrote a category for this issue, which works for me in all cases. See iOS UITableView with dynamic text and images rendered together (NSAttributedString + images)

Working in IOS5 but crash in IOS 6

I'm adding share functionalities to my iOS app (I have to support down to iOS 5.0
The following COde is to Strike a LABEL IT IS WORKING PROPERLY IN IOS5 BUT CRASHING IN IOS 6
Crashing at CGContextStrokePath(c);
CFIndex lineIndex = 0;
for (id line in lines) {
CGFloat ascent = 0.0f, descent = 0.0f, leading = 0.0f;
CGFloat width = CTLineGetTypographicBounds((__bridge CTLineRef)line, &ascent, &descent, &leading) ;
CGRect lineBounds = CGRectMake(0.0f, 0.0f, width, ascent + descent + leading) ;
lineBounds.origin.x = origins[lineIndex].x;
lineBounds.origin.y = origins[lineIndex].y;
for (id glyphRun in (__bridge NSArray *)CTLineGetGlyphRuns((__bridge CTLineRef)line)) {
NSDictionary *attributes = (__bridge NSDictionary *)CTRunGetAttributes((__bridge CTRunRef) glyphRun);
BOOL strikeOut = [[attributes objectForKey:kTTTStrikeOutAttributeName] boolValue];
NSInteger superscriptStyle = [[attributes objectForKey:(id)kCTSuperscriptAttributeName] integerValue];
if (strikeOut) {
CGRect runBounds = CGRectZero;
CGFloat runAscent = 0.0f;
CGFloat runDescent = 0.0f;
runBounds.size.width = CTRunGetTypographicBounds((__bridge CTRunRef)glyphRun, CFRangeMake(0, 0), &runAscent, &runDescent, NULL);
runBounds.size.height = runAscent + runDescent;
CGFloat xOffset = CTLineGetOffsetForStringIndex((__bridge CTLineRef)line, CTRunGetStringRange((__bridge CTRunRef)glyphRun).location, NULL);
runBounds.origin.x = origins[lineIndex].x + rect.origin.x + xOffset;
runBounds.origin.y = origins[lineIndex].y + rect.origin.y;
runBounds.origin.y -= runDescent;
// Don't draw strikeout too far to the right
if (CGRectGetWidth(runBounds) > CGRectGetWidth(lineBounds)) {
runBounds.size.width = CGRectGetWidth(lineBounds);
}
switch (superscriptStyle) {
case 1:
runBounds.origin.y -= runAscent * 0.47f;
break;
case -1:
runBounds.origin.y += runAscent * 0.25f;
break;
default:
break;
}
// Use text color, or default to black
id color = [attributes objectForKey:(id)kCTForegroundColorAttributeName];
if (color) {
CGContextSetStrokeColorWithColor(c, (__bridge CGColorRef)color);
} else {
CGContextSetGrayStrokeColor(c, 0.0f, 1.0);
}
CTFontRef font = CTFontCreateWithName((__bridge CFStringRef)self.font.fontName, self.font.pointSize, NULL);
CGContextSetLineWidth(c, CTFontGetUnderlineThickness(font));
CGFloat y = roundf(runBounds.origin.y + runBounds.size.height / 2.0f);
CGContextMoveToPoint(c, runBounds.origin.x, y);
CGContextAddLineToPoint(c, runBounds.origin.x + runBounds.size.width, y);
CGContextStrokePath(c);
}
}
lineIndex++;
}
}
Its a bug of TTTAttributedLabel check out this issue
Hopefully someone may resolve that and you will get solution. Watchout there until you get solution.

Multi-line NSAttributedString with truncated text

I need a UILabel subcass with multiline attributed text with support for links, bold styles, etc. I also need tail truncation with an ellipsis. None of the open source code that supports attributed text inside UILabels (TTTAttributedLabel, OHAttributedLabel, TTStyledTextLabel) seem to support tail truncation for multi-line text. Is there an easy way to get this?
Maybe I'm missing something, but whats wrong with? :
NSMutableAttributedString *text = [[NSMutableAttributedString alloc] initWithString:#"test"];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
style.lineBreakMode = NSLineBreakByTruncatingTail;
[text addAttribute:NSParagraphStyleAttributeName
value:style
range:NSMakeRange(0, text.length)];
label.attributedText = text;
This works perfectly and will add a ellipsis to the end.
Hi I am the developer of OHAttributedLabel.
There is no easy way to achieve this (as explained in the associated issue I opened on the github repository of my project), because CoreText does not offer such feature.
The only way to do this would be to implement the text layout yourself using CoreText objects (CTLine, etc) instead of using the CTFrameSetter that does this for you (but w/o managing line truncation). The idea would be to build all the CTLines to lay them out (depending on the glyphs in your NSAttributedString it contains and the word wrapping policy) one after the other and manage the ellipsis at the end yourself.
I would really appreciate if someone propose a solution to do this propery as it seems a bit of work to do and you have to manage a range of special/unusual cases too (emoji cases, fonts with odd metrics and unusual glyphs, vertical alignment, take into account the size of the ellipsis itself at the end to know when to stop).
So feel free to dig around and try to implement the framing of the lines yourself it would be really appreciated!
Based on what I found here and over at https://groups.google.com/forum/?fromgroups=#!topic/cocoa-unbound/Qin6gjYj7XU, I came up with the following which works very well.
- (void)drawString:(CFAttributedStringRef)attString inRect:(CGRect)frameRect inContext: (CGContextRef)context
{
CGContextSaveGState(context);
// Flip the coordinate system
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
CGContextTranslateCTM(context, 0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
CGFloat height = self.frame.size.height;
frameRect.origin.y = (height - frameRect.origin.y) - frameRect.size.height ;
// Create a path to render text in
// don't set any line break modes, etc, just let the frame draw as many full lines as will fit
CGMutablePathRef framePath = CGPathCreateMutable();
CGPathAddRect(framePath, nil, frameRect);
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attString);
CFRange fullStringRange = CFRangeMake(0, CFAttributedStringGetLength(attString));
CTFrameRef aFrame = CTFramesetterCreateFrame(framesetter, fullStringRange, framePath, NULL);
CFRelease(framePath);
CFArrayRef lines = CTFrameGetLines(aFrame);
CFIndex count = CFArrayGetCount(lines);
CGPoint *origins = malloc(sizeof(CGPoint)*count);
CTFrameGetLineOrigins(aFrame, CFRangeMake(0, count), origins);
// note that we only enumerate to count-1 in here-- we draw the last line separately
for (CFIndex i = 0; i < count-1; i++)
{
// draw each line in the correct position as-is
CGContextSetTextPosition(context, origins[i].x + frameRect.origin.x, origins[i].y + frameRect.origin.y);
CTLineRef line = (CTLineRef)CFArrayGetValueAtIndex(lines, i);
CTLineDraw(line, context);
}
// truncate the last line before drawing it
if (count) {
CGPoint lastOrigin = origins[count-1];
CTLineRef lastLine = CFArrayGetValueAtIndex(lines, count-1);
// truncation token is a CTLineRef itself
CFRange effectiveRange;
CFDictionaryRef stringAttrs = CFAttributedStringGetAttributes(attString, 0, &effectiveRange);
CFAttributedStringRef truncationString = CFAttributedStringCreate(NULL, CFSTR("\u2026"), stringAttrs);
CTLineRef truncationToken = CTLineCreateWithAttributedString(truncationString);
CFRelease(truncationString);
// now create the truncated line -- need to grab extra characters from the source string,
// or else the system will see the line as already fitting within the given width and
// will not truncate it.
// range to cover everything from the start of lastLine to the end of the string
CFRange rng = CFRangeMake(CTLineGetStringRange(lastLine).location, 0);
rng.length = CFAttributedStringGetLength(attString) - rng.location;
// substring with that range
CFAttributedStringRef longString = CFAttributedStringCreateWithSubstring(NULL, attString, rng);
// line for that string
CTLineRef longLine = CTLineCreateWithAttributedString(longString);
CFRelease(longString);
CTLineRef truncated = CTLineCreateTruncatedLine(longLine, frameRect.size.width, kCTLineTruncationEnd, truncationToken);
CFRelease(longLine);
CFRelease(truncationToken);
// if 'truncated' is NULL, then no truncation was required to fit it
if (truncated == NULL)
truncated = (CTLineRef)CFRetain(lastLine);
// draw it at the same offset as the non-truncated version
CGContextSetTextPosition(context, lastOrigin.x + frameRect.origin.x, lastOrigin.y + frameRect.origin.y);
CTLineDraw(truncated, context);
CFRelease(truncated);
}
free(origins);
CGContextRestoreGState(context);
}
Heres a Swift 5 version of #Toydor's answer:
let attributedString = NSMutableAttributedString(string: "my String")
let style: NSMutableParagraphStyle = NSMutableParagraphStyle()
style.lineBreakMode = .byTruncatingTail
attributedString.addAttribute(NSAttributedString.Key.paragraphStyle,
value: style,
range: NSMakeRange(0, attributedString.length))
I haven't tried this in all cases, but something like this could work for truncation:
NSAttributedString *string = self.attributedString;
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
CFAttributedStringRef attributedString = (__bridge CFTypeRef)string;
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(attributedString);
CGPathRef path = CGPathCreateWithRect(self.bounds, NULL);
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), path, NULL);
BOOL needsTruncation = CTFrameGetVisibleStringRange(frame).length < string.length;
CFArrayRef lines = CTFrameGetLines(frame);
NSUInteger lineCount = CFArrayGetCount(lines);
CGPoint *origins = malloc(sizeof(CGPoint) * lineCount);
CTFrameGetLineOrigins(frame, CFRangeMake(0, 0), origins);
for (NSUInteger i = 0; i < lineCount; i++) {
CTLineRef line = CFArrayGetValueAtIndex(lines, i);
CGPoint point = origins[i];
CGContextSetTextPosition(context, point.x, point.y);
BOOL truncate = (needsTruncation && (i == lineCount - 1));
if (!truncate) {
CTLineDraw(line, context);
}
else {
NSDictionary *attributes = [string attributesAtIndex:string.length-1 effectiveRange:NULL];
NSAttributedString *token = [[NSAttributedString alloc] initWithString:#"\u2026" attributes:attributes];
CFAttributedStringRef tokenRef = (__bridge CFAttributedStringRef)token;
CTLineRef truncationToken = CTLineCreateWithAttributedString(tokenRef);
double width = CTLineGetTypographicBounds(line, NULL, NULL, NULL) - CTLineGetTrailingWhitespaceWidth(line);
CTLineRef truncatedLine = CTLineCreateTruncatedLine(line, width-1, kCTLineTruncationEnd, truncationToken);
if (truncatedLine) { CTLineDraw(truncatedLine, context); }
else { CTLineDraw(line, context); }
if (truncationToken) { CFRelease(truncationToken); }
if (truncatedLine) { CFRelease(truncatedLine); }
}
}
free(origins);
CGPathRelease(path);
CFRelease(frame);
CFRelease(framesetter);
Multi Line Vertical Glyph With Truncated. Swift3 and Swift4 version.
Add: Xcode9.1 Swift4 Compatibility. ( use block "#if swift(>=4.0)" )
class MultiLineVerticalGlyphWithTruncated: UIView, SimpleVerticalGlyphViewProtocol {
var text:String!
var font:UIFont!
var isVertical:Bool!
func setupProperties(text: String?, font:UIFont?, isVertical:Bool) {
self.text = text ?? ""
self.font = font ?? UIFont.systemFont(ofSize: UIFont.systemFontSize)
self.isVertical = isVertical
}
override func draw(_ rect: CGRect) {
if self.text == nil {
return
}
// Create NSMutableAttributedString
let attributed = NSMutableAttributedString(string: text) // if no ruby
//let attributed = text.attributedStringWithRuby() // if with ruby, Please create custom method
#if swift(>=4.0)
attributed.addAttributes([
NSAttributedStringKey.font: font,
NSAttributedStringKey.verticalGlyphForm: isVertical,
],
range: NSMakeRange(0, attributed.length))
#else
attributed.addAttributes([
kCTFontAttributeName as String: font,
kCTVerticalFormsAttributeName as String: isVertical,
],
range: NSMakeRange(0, attributed.length))
#endif
drawContext(attributed, textDrawRect: rect, isVertical: isVertical)
}
}
protocol SimpleVerticalGlyphViewProtocol {
}
extension SimpleVerticalGlyphViewProtocol {
func drawContext(_ attributed:NSMutableAttributedString, textDrawRect:CGRect, isVertical:Bool) {
guard let context = UIGraphicsGetCurrentContext() else { return }
var path:CGPath
if isVertical {
context.rotate(by: .pi / 2)
context.scaleBy(x: 1.0, y: -1.0)
path = CGPath(rect: CGRect(x: textDrawRect.origin.y, y: textDrawRect.origin.x, width: textDrawRect.height, height: textDrawRect.width), transform: nil)
}
else {
context.textMatrix = CGAffineTransform.identity
context.translateBy(x: 0, y: textDrawRect.height)
context.scaleBy(x: 1.0, y: -1.0)
path = CGPath(rect: textDrawRect, transform: nil)
}
let framesetter = CTFramesetterCreateWithAttributedString(attributed)
let frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, attributed.length), path, nil)
// Check need for truncate tail
if (CTFrameGetVisibleStringRange(frame).length as Int) < attributed.length {
// Required truncate
let linesNS: NSArray = CTFrameGetLines(frame)
let linesAO: [AnyObject] = linesNS as [AnyObject]
var lines: [CTLine] = linesAO as! [CTLine]
let boundingBoxOfPath = path.boundingBoxOfPath
let lastCTLine = lines.removeLast()
let truncateString:CFAttributedString = CFAttributedStringCreate(nil, "\u{2026}" as CFString, CTFrameGetFrameAttributes(frame))
let truncateToken:CTLine = CTLineCreateWithAttributedString(truncateString)
let lineWidth = CTLineGetTypographicBounds(lastCTLine, nil, nil, nil)
let tokenWidth = CTLineGetTypographicBounds(truncateToken, nil, nil, nil)
let widthTruncationBegins = lineWidth - tokenWidth
if let truncatedLine = CTLineCreateTruncatedLine(lastCTLine, widthTruncationBegins, .end, truncateToken) {
lines.append(truncatedLine)
}
var lineOrigins = Array<CGPoint>(repeating: CGPoint.zero, count: lines.count)
CTFrameGetLineOrigins(frame, CFRange(location: 0, length: lines.count), &lineOrigins)
for (index, line) in lines.enumerated() {
context.textPosition = CGPoint(x: lineOrigins[index].x + boundingBoxOfPath.origin.x, y:lineOrigins[index].y + boundingBoxOfPath.origin.y)
CTLineDraw(line, context)
}
}
else {
// Not required truncate
CTFrameDraw(frame, context)
}
}
}
How to use
class ViewController: UIViewController {
#IBOutlet weak var multiLineVerticalGlyphWithTruncated: MultiLineVerticalGlyphWithTruncated! // UIView
let font:UIFont = UIFont(name: "HiraMinProN-W3", size: 17.0) ?? UIFont.systemFont(ofSize: 17.0)
override func viewDidLoad() {
super.viewDidLoad()
let text = "iOS 11 sets a new standard for what is already the world’s most advanced mobile operating system. It makes iPhone better than before. It makes iPad more capable than ever. And now it opens up both to amazing possibilities for augmented reality in games and apps. With iOS 11, iPhone and iPad are the most powerful, personal, and intelligent devices they’ve ever been."
// If check for Japanese
// let text = "すでに世界で最も先進的なモバイルオペレーティングシステムであるiOSに、iOS 11が新たな基準を打ち立てます。iPhoneは今まで以上に優れたものになり、iPadはかつてないほどの能力を手に入れます。さらにこれからはどちらのデバイスにも、ゲームやアプリケーションの拡張現実のための驚くような可能性が広がります。iOS 11を搭載するiPhoneとiPadは、間違いなくこれまでで最もパワフルで、最もパーソナルで、最も賢いデバイスです。"
// if not vertical text, isVertical = false
multiLineVerticalGlyphWithTruncated.setupProperties(text: text, font: font, isVertical: true)
}
}
You may be able to use follow code to have a more simple solution.
// last line.
if (_limitToNumberOfLines && count == _numberOfLines-1)
{
// check if we reach end of text.
if (lineRange.location + lineRange.length < [_text length])
{
CFDictionaryRef dict = ( CFDictionaryRef)attributes;
CFAttributedStringRef truncatedString = CFAttributedStringCreate(NULL, CFSTR("\u2026"), dict);
CTLineRef token = CTLineCreateWithAttributedString(truncatedString);
// not possible to display all text, add tail ellipsis.
CTLineRef truncatedLine = CTLineCreateTruncatedLine(line, self.bounds.size.width - 20, kCTLineTruncationEnd, token);
CFRelease(line); line = nil;
line = truncatedLine;
}
}
I'm using MTLabel in my project and it's a really nice solution for my project.
I integrated wbyoung's solution into OHAttributedLabel drawTextInRect: method if anyone is interested:
- (void)drawTextInRect:(CGRect)aRect
{
if (_attributedText)
{
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSaveGState(ctx);
// flipping the context to draw core text
// no need to flip our typographical bounds from now on
CGContextConcatCTM(ctx, CGAffineTransformScale(CGAffineTransformMakeTranslation(0, self.bounds.size.height), 1.f, -1.f));
if (self.shadowColor)
{
CGContextSetShadowWithColor(ctx, self.shadowOffset, 0.0, self.shadowColor.CGColor);
}
[self recomputeLinksInTextIfNeeded];
NSAttributedString* attributedStringToDisplay = _attributedTextWithLinks;
if (self.highlighted && self.highlightedTextColor != nil)
{
NSMutableAttributedString* mutAS = [attributedStringToDisplay mutableCopy];
[mutAS setTextColor:self.highlightedTextColor];
attributedStringToDisplay = mutAS;
(void)MRC_AUTORELEASE(mutAS);
}
if (textFrame == NULL)
{
CFAttributedStringRef cfAttrStrWithLinks = (BRIDGE_CAST CFAttributedStringRef)attributedStringToDisplay;
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(cfAttrStrWithLinks);
drawingRect = self.bounds;
if (self.centerVertically || self.extendBottomToFit)
{
CGSize sz = CTFramesetterSuggestFrameSizeWithConstraints(framesetter,CFRangeMake(0,0),NULL,CGSizeMake(drawingRect.size.width,CGFLOAT_MAX),NULL);
if (self.extendBottomToFit)
{
CGFloat delta = MAX(0.f , ceilf(sz.height - drawingRect.size.height))+ 10 /* Security margin */;
drawingRect.origin.y -= delta;
drawingRect.size.height += delta;
}
if (self.centerVertically) {
drawingRect.origin.y -= (drawingRect.size.height - sz.height)/2;
}
}
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, drawingRect);
CFRange fullStringRange = CFRangeMake(0, CFAttributedStringGetLength(cfAttrStrWithLinks));
textFrame = CTFramesetterCreateFrame(framesetter,fullStringRange, path, NULL);
CGPathRelease(path);
CFRelease(framesetter);
}
// draw highlights for activeLink
if (_activeLink)
{
[self drawActiveLinkHighlightForRect:drawingRect];
}
BOOL hasLinkFillColorSelector = [self.delegate respondsToSelector:#selector(attributedLabel:fillColorForLink:underlineStyle:)];
if (hasLinkFillColorSelector) {
[self drawInactiveLinkHighlightForRect:drawingRect];
}
if (self.truncLastLine) {
CFArrayRef lines = CTFrameGetLines(textFrame);
CFIndex count = MIN(CFArrayGetCount(lines),floor(self.size.height/self.font.lineHeight));
CGPoint *origins = malloc(sizeof(CGPoint)*count);
CTFrameGetLineOrigins(textFrame, CFRangeMake(0, count), origins);
// note that we only enumerate to count-1 in here-- we draw the last line separately
for (CFIndex i = 0; i < count-1; i++)
{
// draw each line in the correct position as-is
CGContextSetTextPosition(ctx, origins[i].x + drawingRect.origin.x, origins[i].y + drawingRect.origin.y);
CTLineRef line = (CTLineRef)CFArrayGetValueAtIndex(lines, i);
CTLineDraw(line, ctx);
}
// truncate the last line before drawing it
if (count) {
CGPoint lastOrigin = origins[count-1];
CTLineRef lastLine = CFArrayGetValueAtIndex(lines, count-1);
// truncation token is a CTLineRef itself
CFRange effectiveRange;
CFDictionaryRef stringAttrs = CFAttributedStringGetAttributes((BRIDGE_CAST CFAttributedStringRef)_attributedTextWithLinks, 0, &effectiveRange);
CFAttributedStringRef truncationString = CFAttributedStringCreate(NULL, CFSTR("\u2026"), stringAttrs);
CTLineRef truncationToken = CTLineCreateWithAttributedString(truncationString);
CFRelease(truncationString);
// now create the truncated line -- need to grab extra characters from the source string,
// or else the system will see the line as already fitting within the given width and
// will not truncate it.
// range to cover everything from the start of lastLine to the end of the string
CFRange rng = CFRangeMake(CTLineGetStringRange(lastLine).location, 0);
rng.length = CFAttributedStringGetLength((BRIDGE_CAST CFAttributedStringRef)_attributedTextWithLinks) - rng.location;
// substring with that range
CFAttributedStringRef longString = CFAttributedStringCreateWithSubstring(NULL, (BRIDGE_CAST CFAttributedStringRef)_attributedTextWithLinks, rng);
// line for that string
CTLineRef longLine = CTLineCreateWithAttributedString(longString);
CFRelease(longString);
CTLineRef truncated = CTLineCreateTruncatedLine(longLine, drawingRect.size.width, kCTLineTruncationEnd, truncationToken);
CFRelease(longLine);
CFRelease(truncationToken);
// if 'truncated' is NULL, then no truncation was required to fit it
if (truncated == NULL){
truncated = (CTLineRef)CFRetain(lastLine);
}
// draw it at the same offset as the non-truncated version
CGContextSetTextPosition(ctx, lastOrigin.x + drawingRect.origin.x, lastOrigin.y + drawingRect.origin.y);
CTLineDraw(truncated, ctx);
CFRelease(truncated);
}
free(origins);
}
else{
CTFrameDraw(textFrame, ctx);
}
CGContextRestoreGState(ctx);
} else {
[super drawTextInRect:aRect];
}
}
Ran into this issue here in 2021.
I wrapped #Toydor's and #gypsyDev's answer into a UILabel extension so it can be applied where needed. Swift 5.
extension UILabel {
func ensureAttributedTextShowsTruncation() {
guard let text = attributedText else { return }
let attributedString = NSMutableAttributedString(attributedString: text)
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineBreakMode = .byTruncatingTail
attributedString.addAttribute(.paragraphStyle,
value: paragraphStyle,
range: NSRange(location: 0, length: attributedString.length))
attributedText = attributedString
}
}
I used as sample MTLabel. It allows to manage line height.
I needed the draw method exactly, so i just put away most stuff i did not need.
This method allows me to draw multilined text in rect with tail truncation.
CGRect CTLineGetTypographicBoundsAsRect(CTLineRef line, CGPoint lineOrigin)
{
CGFloat ascent = 0;
CGFloat descent = 0;
CGFloat leading = 0;
CGFloat width = CTLineGetTypographicBounds(line, &ascent, &descent, &leading);
CGFloat height = ascent + descent;
return CGRectMake(lineOrigin.x,
lineOrigin.y - descent,
width,
height);
}
- (void)drawText:(NSString*) text InRect:(CGRect)rect withFont:(UIFont*)aFont inContext:(CGContextRef)context {
if (!text) {
return;
}
BOOL _limitToNumberOfLines = YES;
int _numberOfLines = 2;
float _lineHeight = 22;
//Create a CoreText font object with name and size from the UIKit one
CTFontRef font = CTFontCreateWithName((CFStringRef)aFont.fontName ,
aFont.pointSize,
NULL);
//Setup the attributes dictionary with font and color
NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:
(id)font, (id)kCTFontAttributeName,
[UIColor lightGrayColor].CGColor, kCTForegroundColorAttributeName,
nil];
NSAttributedString *attributedString = [[[NSAttributedString alloc]
initWithString:text
attributes:attributes] autorelease];
CFRelease(font);
//Create a TypeSetter object with the attributed text created earlier on
CTTypesetterRef typeSetter = CTTypesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);
//Start drawing from the upper side of view (the context is flipped, so we need to grab the height to do so)
CGFloat y = self.bounds.origin.y + self.bounds.size.height - rect.origin.y - aFont.ascender;
BOOL shouldDrawAlong = YES;
int count = 0;
CFIndex currentIndex = 0;
float _textHeight = 0;
CGContextSaveGState(context);
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
CGContextTranslateCTM(context, 0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
//Start drawing lines until we run out of text
while (shouldDrawAlong) {
//Get CoreText to suggest a proper place to place the line break
CFIndex lineLength = CTTypesetterSuggestLineBreak(typeSetter,
currentIndex,
rect.size.width);
//Create a new line with from current index to line-break index
CFRange lineRange = CFRangeMake(currentIndex, lineLength);
CTLineRef line = CTTypesetterCreateLine(typeSetter, lineRange);
//Check to see if our index didn't exceed the text, and if should limit to number of lines
if (currentIndex + lineLength >= [text length])
{
shouldDrawAlong = NO;
}
else
{
if (!(_limitToNumberOfLines && count < _numberOfLines-1))
{
int i = 0;
if ([[[text substringWithRange:NSMakeRange(currentIndex, lineLength)] stringByAppendingString:#"…"] sizeWithFont:aFont].width > rect.size.width)
{
i--;
while ([[[text substringWithRange:NSMakeRange(currentIndex, lineLength + i)] stringByAppendingString:#"…"] sizeWithFont:aFont].width > rect.size.width)
{
i--;
}
}
else
{
i++;
while ([[[text substringWithRange:NSMakeRange(currentIndex, lineLength + i)] stringByAppendingString:#"…"] sizeWithFont:aFont].width < rect.size.width)
{
i++;
}
i--;
}
attributedString = [[[NSAttributedString alloc] initWithString:[[text substringWithRange:NSMakeRange(currentIndex, lineLength + i)] stringByAppendingString:#"…"] attributes:attributes] autorelease];
CFRelease(typeSetter);
typeSetter = CTTypesetterCreateWithAttributedString((CFAttributedStringRef)attributedString);
CFRelease(line);
CFRange lineRange = CFRangeMake(0, 0);
line = CTTypesetterCreateLine(typeSetter, lineRange);
shouldDrawAlong = NO;
}
}
CGFloat x = rect.origin.x;
//Setup the line position
CGContextSetTextPosition(context, x, y);
CTLineDraw(line, context);
count++;
CFRelease(line);
y -= _lineHeight;
currentIndex += lineLength;
_textHeight += _lineHeight;
}
CFRelease(typeSetter);
CGContextRestoreGState(context);
}

Resources