Texto de curva no círculo existente

Para um aplicativo que estou construindo, desenhei 2 círculos. Um um pouco maior que o outro. Eu quero curvar o texto entre essas linhas, para um menu circular que estou construindo.

Eu leio a maioria das coisas sobre como curvar um texto que você tem que dividir o seu texto em caracteres e desenhar cada personagem por conta própria com o ângulo reto em mente (girando o contexto em que você está desenhando).

Eu simplesmente não consigo entender como obter os ângulos e posições corretos para os meus personagens.

Eu incluí uma captura de canvas sobre o que o menu, no momento, parece. Somente os textos que adicionei são carregados de uma imagem em um UIImageView.

texto alternativo

Espero que alguém possa me dar alguns pontos de partida sobre como eu posso desenhar o texto no círculo branco, em certos pontos.

EDIT: Ok, estou neste momento neste momento:

texto alternativo

Eu realizo usando o seguinte código:

- (UIImage*) createMenuRingWithFrame:(CGRect)frame { CGRect imageSize = CGRectMake(0,0,300,300); float perSectionDegrees = 360 / [sections count]; float totalRotation = 90; char* fontName = (char*)[self.menuItemsFont.fontName cStringUsingEncoding:NSASCIIStringEncoding]; CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGContextRef context = CGBitmapContextCreate(NULL, imageSize.size.width, imageSize.size.height, 8, 4 * imageSize.size.width, colorSpace, kCGImageAlphaPremultipliedFirst); CGContextSetTextMatrix(context, CGAffineTransformIdentity); CGContextSelectFont(context, fontName, 18, kCGEncodingMacRoman); CGContextSetRGBFillColor(context, 0, 0, 0, 1); CGPoint centerPoint = CGPointMake(imageSize.size.width / 2, imageSize.size.height / 2); double radius = (frame.size.width / 2); CGContextStrokeEllipseInRect(context, CGRectMake(centerPoint.x - (frame.size.width / 2), centerPoint.y - (frame.size.height / 2), frame.size.width, frame.size.height)); for (int index = 0; index < [sections count]; index++) { NSString* menuItemText = [sections objectAtIndex:index]; CGSize textSize = [menuItemText sizeWithFont:self.menuItemsFont]; char* menuItemTextChar = (char*)[menuItemText cStringUsingEncoding:NSASCIIStringEncoding]; float x = centerPoint.x + radius * cos(degreesToRadians(totalRotation)); float y = centerPoint.y + radius * sin(degreesToRadians(totalRotation)); CGContextSaveGState(context); CGContextTranslateCTM(context, x, y); CGContextRotateCTM(context, degreesToRadians(totalRotation - 90)); CGContextShowTextAtPoint(context, 0 - (textSize.width / 2), 0 - (textSize.height / 2), menuItemTextChar, strlen(menuItemTextChar)); CGContextRestoreGState(context); totalRotation += perSectionDegrees; } CGImageRef contextImage = CGBitmapContextCreateImage(context); CGContextRelease(context); CGColorSpaceRelease(colorSpace); return [UIImage imageWithCGImage:contextImage]; } 

Estas são as variables ​​que eu uso lá:

 NSArray* sections = [[NSArray alloc] initWithObjects:@"settings", @"test", @"stats", @"nog iets", @"woei", @"woei2", nil]; self.menuItemsFont = [UIFont fontWithName:@"VAGRounded-Bold" size:18]; 

A rotação das palavras parece correta, o posicionamento também. Agora eu preciso de alguma forma descobrir em que rotação as letras (e suas coordenadas) devem estar. Eu poderia usar alguma ajuda com isso.

Edit: Fixo! Confira o seguinte código!

 - (void) drawStringAtContext:(CGContextRef) context string:(NSString*) text atAngle:(float) angle withRadius:(float) radius { CGSize textSize = [text sizeWithFont:self.menuItemsFont]; float perimeter = 2 * M_PI * radius; float textAngle = textSize.width / perimeter * 2 * M_PI; angle += textAngle / 2; for (int index = 0; index < [text length]; index++) { NSRange range = {index, 1}; NSString* letter = [text substringWithRange:range]; char* c = (char*)[letter cStringUsingEncoding:NSASCIIStringEncoding]; CGSize charSize = [letter sizeWithFont:self.menuItemsFont]; NSLog(@"Char %@ with size: %fx %f", letter, charSize.width, charSize.height); float x = radius * cos(angle); float y = radius * sin(angle); float letterAngle = (charSize.width / perimeter * -2 * M_PI); CGContextSaveGState(context); CGContextTranslateCTM(context, x, y); CGContextRotateCTM(context, (angle - 0.5 * M_PI)); CGContextShowTextAtPoint(context, 0, 0, c, strlen(c)); CGContextRestoreGState(context); angle += letterAngle; } } - (UIImage*) createMenuRingWithFrame:(CGRect)frame { CGPoint centerPoint = CGPointMake(frame.size.width / 2, frame.size.height / 2); char* fontName = (char*)[self.menuItemsFont.fontName cStringUsingEncoding:NSASCIIStringEncoding]; CGFloat* ringColorComponents = (float*)CGColorGetComponents(ringColor.CGColor); CGFloat* textColorComponents = (float*)CGColorGetComponents(textColor.CGColor); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGContextRef context = CGBitmapContextCreate(NULL, frame.size.width, frame.size.height, 8, 4 * frame.size.width, colorSpace, kCGImageAlphaPremultipliedFirst); CGContextSetTextMatrix(context, CGAffineTransformIdentity); CGContextSelectFont(context, fontName, 18, kCGEncodingMacRoman); CGContextSetRGBStrokeColor(context, ringColorComponents[0], ringColorComponents[1], ringColorComponents[2], ringAlpha); CGContextSetLineWidth(context, ringWidth); CGContextStrokeEllipseInRect(context, CGRectMake(ringWidth, ringWidth, frame.size.width - (ringWidth * 2), frame.size.height - (ringWidth * 2))); CGContextSetRGBFillColor(context, textColorComponents[0], textColorComponents[1], textColorComponents[2], textAlpha); CGContextSaveGState(context); CGContextTranslateCTM(context, centerPoint.x, centerPoint.y); float angleStep = 2 * M_PI / [sections count]; float angle = degreesToRadians(90); textRadius = textRadius - 12; for (NSString* text in sections) { [self drawStringAtContext:context string:text atAngle:angle withRadius:textRadius]; angle -= angleStep; } CGContextRestoreGState(context); CGImageRef contextImage = CGBitmapContextCreateImage(context); CGContextRelease(context); CGColorSpaceRelease(colorSpace); [self saveImage:[UIImage imageWithCGImage:contextImage] withName:@"test.png"]; return [UIImage imageWithCGImage:contextImage]; } 

Eu tentei resolver isso rapidamente no papel, então eu posso estar errado 🙂

Converta o comprimento da string em unidades no UnitCircle . Assim (string.lenght / circle perimeter) * 2Pi. Você agora tem o ângulo em radianos para toda a string. (Esse é o ângulo entre o início e o fim da string)

Para as letras separadas, você poderia fazer o mesmo para obter o ângulo (em radianos) para letras individuais (usando larguras de letra)

Depois de ter o ângulo em radianos, você pode calcular a posição xey (e rotação) das letras.

Bônus: para espaçamento uniforme, você pode até calcular a razão entre o comprimento total de todas as cordas e todo o perímetro. E divida o espaço restante igualmente entre a corda.

Atualização Eu fiz uma prova de conceito usando html5 / canvas, então visualize-o com um navegador decente 🙂 Você deve ser capaz de portá-lo. (lembre-se, o código não é comentado)
wtf: o código roda bem com o console de debugging do chrome aberto e falha quando é fechado. (solução alternativa: console do chrome aberto: ctrl-shift-j e recarregar a página: f5); FF3.6.8 parece estar bem, mas as letras “dançam”.

Eu adaptei o projeto de amostra CoreTextArcCocoa da Apple (mencionado por Tom H nesta resposta ) e pensei em compartilhá-lo aqui.

Eu adicionei alguns outros resources também, como a capacidade de definir o tamanho do arco para algo menor que 180, e a cor do texto e deslocamento deslocam-se como propriedades (para que você não precise ter um quadro enorme para mostrar o todo texto).

  /* File: CoreTextArcView.m (iOS version) Abstract: Defines and implements the CoreTextArcView custom UIView subclass to draw text on a curve and illustrate best practices with CoreText. Based on CoreTextArcView provided by Apple for Mac OS X https://developer.apple.com/library/mac/#samplecode/CoreTextArcCocoa/Introduction/Intro.html Ported to iOS (& added color, arcsize features) August 2011 by Alec Vance, Juggleware LLC http://juggleware.com/ */ #import  #import  @interface CoreTextArcView : UIView { @private UIFont * _font; NSString * _string; CGFloat _radius; UIColor * _color; CGFloat _arcSize; CGFloat _shiftH, _shiftV; // horiz & vertical shift struct { unsigned int showsGlyphBounds:1; unsigned int showsLineMetrics:1; unsigned int dimsSubstitutedGlyphs:1; unsigned int reserved:29; } _flags; } @property(retain, nonatomic) UIFont *font; @property(retain, nonatomic) NSString *text; @property(readonly, nonatomic) NSAttributedString *attributedString; @property(assign, nonatomic) CGFloat radius; @property(nonatomic) BOOL showsGlyphBounds; @property(nonatomic) BOOL showsLineMetrics; @property(nonatomic) BOOL dimsSubstitutedGlyphs; @property(retain, nonatomic) UIColor *color; @property(nonatomic) CGFloat arcSize; @property(nonatomic) CGFloat shiftH, shiftV; @end /* File: CoreTextArcView.m (iOS version) */ #import "CoreTextArcView.h" #import  #import  #define ARCVIEW_DEBUG_MODE NO #define ARCVIEW_DEFAULT_FONT_NAME @"Helvetica" #define ARCVIEW_DEFAULT_FONT_SIZE 64.0 #define ARCVIEW_DEFAULT_RADIUS 150.0 #define ARCVIEW_DEFAULT_ARC_SIZE 180.0 @implementation CoreTextArcView - (id)initWithFrame:(CGRect)frame { self = [super initWithFrame:frame]; if (self) { self.font = [UIFont fontWithName:ARCVIEW_DEFAULT_FONT_NAME size:ARCVIEW_DEFAULT_FONT_SIZE]; self.text = @"Curvaceous Type"; self.radius = ARCVIEW_DEFAULT_RADIUS; self.showsGlyphBounds = NO; self.showsLineMetrics = NO; self.dimsSubstitutedGlyphs = NO; self.color = [UIColor whiteColor]; self.arcSize = ARCVIEW_DEFAULT_ARC_SIZE; self.shiftH = self.shiftV = 0.0f; } return self; } typedef struct GlyphArcInfo { CGFloat width; CGFloat angle; // in radians } GlyphArcInfo; static void PrepareGlyphArcInfo(CTLineRef line, CFIndex glyphCount, GlyphArcInfo *glyphArcInfo, CGFloat arcSizeRad) { NSArray *runArray = (NSArray *)CTLineGetGlyphRuns(line); // Examine each run in the line, updating glyphOffset to track how far along the run is in terms of glyphCount. CFIndex glyphOffset = 0; for (id run in runArray) { CFIndex runGlyphCount = CTRunGetGlyphCount((CTRunRef)run); // Ask for the width of each glyph in turn. CFIndex runGlyphIndex = 0; for (; runGlyphIndex < runGlyphCount; runGlyphIndex++) { glyphArcInfo[runGlyphIndex + glyphOffset].width = CTRunGetTypographicBounds((CTRunRef)run, CFRangeMake(runGlyphIndex, 1), NULL, NULL, NULL); } glyphOffset += runGlyphCount; } double lineLength = CTLineGetTypographicBounds(line, NULL, NULL, NULL); CGFloat prevHalfWidth = glyphArcInfo[0].width / 2.0; glyphArcInfo[0].angle = (prevHalfWidth / lineLength) * arcSizeRad; // Divide the arc into slices such that each one covers the distance from one glyph's center to the next. CFIndex lineGlyphIndex = 1; for (; lineGlyphIndex < glyphCount; lineGlyphIndex++) { CGFloat halfWidth = glyphArcInfo[lineGlyphIndex].width / 2.0; CGFloat prevCenterToCenter = prevHalfWidth + halfWidth; glyphArcInfo[lineGlyphIndex].angle = (prevCenterToCenter / lineLength) * arcSizeRad; prevHalfWidth = halfWidth; } } // ensure that redraw occurs. -(void)setText:(NSString *)text{ [_string release]; _string = [text retain]; [self setNeedsDisplay]; } //set arc size in degrees (180 = half circle) -(void)setArcSize:(CGFloat)degrees{ _arcSize = degrees * M_PI/180.0; } //get arc size in degrees -(CGFloat)arcSize{ return _arcSize * 180.0/M_PI; } - (void)drawRect:(CGRect)rect { // Don't draw if we don't have a font or string if (self.font == NULL || self.text == NULL) return; // Initialize the text matrix to a known value CGContextRef context = UIGraphicsGetCurrentContext(); //Reset the transformation //Doing this means you have to reset the contentScaleFactor to 1.0 CGAffineTransform t0 = CGContextGetCTM(context); CGFloat xScaleFactor = t0.a > 0 ? t0.a : -t0.a; CGFloat yScaleFactor = t0.d > 0 ? t0.d : -t0.d; t0 = CGAffineTransformInvert(t0); if (xScaleFactor != 1.0 || yScaleFactor != 1.0) t0 = CGAffineTransformScale(t0, xScaleFactor, yScaleFactor); CGContextConcatCTM(context, t0); CGContextSetTextMatrix(context, CGAffineTransformIdentity); if(ARCVIEW_DEBUG_MODE){ // Draw a black background (debug) CGContextSetFillColorWithColor(context, [UIColor blackColor].CGColor); CGContextFillRect(context, self.layer.bounds); } NSAttributedString *attStr = self.attributedString; CFAttributedStringRef asr = (CFAttributedStringRef)attStr; CTLineRef line = CTLineCreateWithAttributedString(asr); assert(line != NULL); CFIndex glyphCount = CTLineGetGlyphCount(line); if (glyphCount == 0) { CFRelease(line); return; } GlyphArcInfo * glyphArcInfo = (GlyphArcInfo*)calloc(glyphCount, sizeof(GlyphArcInfo)); PrepareGlyphArcInfo(line, glyphCount, glyphArcInfo, _arcSize); // Move the origin from the lower left of the view nearer to its center. CGContextSaveGState(context); CGContextTranslateCTM(context, CGRectGetMidX(rect)+_shiftH, CGRectGetMidY(rect)+_shiftV - self.radius / 2.0); if(ARCVIEW_DEBUG_MODE){ // Stroke the arc in red for verification. CGContextBeginPath(context); CGContextAddArc(context, 0.0, 0.0, self.radius, M_PI_2+_arcSize/2.0, M_PI_2-_arcSize/2.0, 1); CGContextSetRGBStrokeColor(context, 1.0, 0.0, 0.0, 1.0); CGContextStrokePath(context); } // Rotate the context 90 degrees counterclockwise (per 180 degrees) CGContextRotateCTM(context, _arcSize/2.0); // Now for the actual drawing. The angle offset for each glyph relative to the previous glyph has already been calculated; with that information in hand, draw those glyphs overstruck and centered over one another, making sure to rotate the context after each glyph so the glyphs are spread along a semicircular path. CGPoint textPosition = CGPointMake(0.0, self.radius); CGContextSetTextPosition(context, textPosition.x, textPosition.y); CFArrayRef runArray = CTLineGetGlyphRuns(line); CFIndex runCount = CFArrayGetCount(runArray); CFIndex glyphOffset = 0; CFIndex runIndex = 0; for (; runIndex < runCount; runIndex++) { CTRunRef run = (CTRunRef)CFArrayGetValueAtIndex(runArray, runIndex); CFIndex runGlyphCount = CTRunGetGlyphCount(run); Boolean drawSubstitutedGlyphsManually = false; CTFontRef runFont = CFDictionaryGetValue(CTRunGetAttributes(run), kCTFontAttributeName); // Determine if we need to draw substituted glyphs manually. Do so if the runFont is not the same as the overall font. if (self.dimsSubstitutedGlyphs && ![self.font isEqual:(UIFont *)runFont]) { drawSubstitutedGlyphsManually = true; } CFIndex runGlyphIndex = 0; for (; runGlyphIndex < runGlyphCount; runGlyphIndex++) { CFRange glyphRange = CFRangeMake(runGlyphIndex, 1); CGContextRotateCTM(context, -(glyphArcInfo[runGlyphIndex + glyphOffset].angle)); // Center this glyph by moving left by half its width. CGFloat glyphWidth = glyphArcInfo[runGlyphIndex + glyphOffset].width; CGFloat halfGlyphWidth = glyphWidth / 2.0; CGPoint positionForThisGlyph = CGPointMake(textPosition.x - halfGlyphWidth, textPosition.y); // Glyphs are positioned relative to the text position for the line, so offset text position leftwards by this glyph's width in preparation for the next glyph. textPosition.x -= glyphWidth; CGAffineTransform textMatrix = CTRunGetTextMatrix(run); textMatrix.tx = positionForThisGlyph.x; textMatrix.ty = positionForThisGlyph.y; CGContextSetTextMatrix(context, textMatrix); if (!drawSubstitutedGlyphsManually) { CTRunDraw(run, context, glyphRange); } else { // We need to draw the glyphs manually in this case because we are effectively applying a graphics operation by setting the context fill color. Normally we would use kCTForegroundColorAttributeName, but this does not apply as we don't know the ranges for the colors in advance, and we wanted demonstrate how to manually draw. CGFontRef cgFont = CTFontCopyGraphicsFont(runFont, NULL); CGGlyph glyph; CGPoint position; CTRunGetGlyphs(run, glyphRange, &glyph); CTRunGetPositions(run, glyphRange, &position); CGContextSetFont(context, cgFont); CGContextSetFontSize(context, CTFontGetSize(runFont)); CGContextSetRGBFillColor(context, 0.25, 0.25, 0.25, 0.5); CGContextShowGlyphsAtPositions(context, &glyph, &position, 1); CFRelease(cgFont); } // Draw the glyph bounds if ((self.showsGlyphBounds) != 0) { CGRect glyphBounds = CTRunGetImageBounds(run, context, glyphRange); CGContextSetRGBStrokeColor(context, 0.0, 0.0, 1.0, 1.0); CGContextStrokeRect(context, glyphBounds); } // Draw the bounding boxes defined by the line metrics if ((self.showsLineMetrics) != 0) { CGRect lineMetrics; CGFloat ascent, descent; CTRunGetTypographicBounds(run, glyphRange, &ascent, &descent, NULL); // The glyph is centered around the y-axis lineMetrics.origin.x = -halfGlyphWidth; lineMetrics.origin.y = positionForThisGlyph.y - descent; lineMetrics.size.width = glyphWidth; lineMetrics.size.height = ascent + descent; CGContextSetRGBStrokeColor(context, 0.0, 1.0, 0.0, 1.0); CGContextStrokeRect(context, lineMetrics); } } glyphOffset += runGlyphCount; } CGContextRestoreGState(context); free(glyphArcInfo); CFRelease(line); } -(void)dealloc { [_font release]; [_string release]; [_color release]; [super dealloc] } @synthesize font = _font; @synthesize text = _string; @synthesize radius = _radius; @synthesize color = _color; @synthesize arcSize = _arcSize; @synthesize shiftH = _shiftH; @synthesize shiftV = _shiftV; @dynamic attributedString; - (NSAttributedString *)attributedString { // Create an attributed string with the current font and string. assert(self.font != nil); assert(self.text != nil); // Create our attributes... // font CTFontRef fontRef = CTFontCreateWithName((CFStringRef)self.font.fontName, self.font.pointSize, NULL); // color CGColorRef colorRef = self.color.CGColor; // pack it into attributes dictionary NSDictionary *attributesDict = [NSDictionary dictionaryWithObjectsAndKeys: (id)fontRef, (id)kCTFontAttributeName, colorRef, (id)kCTForegroundColorAttributeName, nil]; assert(attributesDict != nil); // Create the attributed string NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:self.text attributes:attributesDict]; CFRelease(fontRef); return [attrString autorelease]; } @dynamic showsGlyphBounds; - (BOOL)showsGlyphBounds { return _flags.showsGlyphBounds; } - (void)setShowsGlyphBounds:(BOOL)show { _flags.showsGlyphBounds = show ? 1 : 0; } @dynamic showsLineMetrics; - (BOOL)showsLineMetrics { return _flags.showsLineMetrics; } - (void)setShowsLineMetrics:(BOOL)show { _flags.showsLineMetrics = show ? 1 : 0; } @dynamic dimsSubstitutedGlyphs; - (BOOL)dimsSubstitutedGlyphs { return _flags.dimsSubstitutedGlyphs; } - (void)setDimsSubstitutedGlyphs:(BOOL)dim { _flags.dimsSubstitutedGlyphs = dim ? 1 : 0; } @end 

Para poupar algum tempo, aqui está o que eu encontrei para o CoreTextArcView que expõe

 - (id)initWithFrame:(CGRect)frame font:(UIFont *)font text:(NSString *)text radius:(float)radius arcSize:(float)arcSize color:(UIColor *)color; 
  (x, y) <--------------- w --------------->
       + ------------------------------------------------- +
      ^ |  |  <-
      ||  |  quadro, Armação
      ||  |
      ||  VED LA BEL |
      ||  CU R HE |
      ||  x x RE x |
       |  xx xxx |
       |  xxx xx x xxx |
     h |  xxx xx xxx xx |
       |  x xxx <-----------------------------
       |  xx xx xxxxxxx xx x |  arcSize:
      ||  xx xxx xx xx |  ângulo de abertura
      ||  x xxx xx x |  em graus
      ||  xx xx xxx x |
      ||  x <---- r -----> xx |
      ||  x (xc, yc) x |
      ||  x <-----------------------
      ||  x xx |  xc = x + w / 2
      v + --- xx -------------------------------------- xx ----- + yc = y + h / 2 + r / 2
            xx xx
             x xx
             xxx xx
               xxx xxx
                 xxxx xxxx
                    xxxxx xxxxx
                         xxxxxxxxxxxxxxx 

isso é válido para r> 0 e arcsize> 0.

Confira este projeto de amostra da Apple: CoreTextArcCocoa

Demonstra o uso do Texto Principal para desenhar texto ao longo de um arco em um aplicativo Cocoa. Além disso, este exemplo ilustra como você pode usar o painel de fonts Cocoa para receber configurações de fonts que podem ser usadas pelo Texto principal para selecionar a fonte usada para o desenho.

CoreText também está disponível no iOS, então você deve ser capaz de implementar algo semelhante.

Eu tentei o projeto git mencionado acima, e como ZpaceZombor disse, há um offset errado

 CGContextTranslateCTM(context, CGRectGetMidX(rect)+_shiftH, CGRectGetMidY(rect)+_shiftV - self.radius / 2.0); 

Eu mudei simplesmente para

 CGContextTranslateCTM(context, CGRectGetMidX(rect)+_shiftH, CGRectGetMidY(rect)+_shiftV); 

Eu configurei o raio para o valor Mínimo entre a largura e a altura da visualização do contêiner, então configurei o tamanho do arco para .

Eu mudei arbitrariamente a linha

 CGContextRotateCTM(context, _arcSize/2.0); 

com

 CGContextRotateCTM(context, M_PI_2); 

Eu mudei o método init para

 - (id)initWithFrame:(CGRect)frame font:(UIFont *)font text:(NSString *)text color:(UIColor *)color{ self = [super initWithFrame:frame]; if (self) { self.font = font; self.text = text; self.radius = -1 * (frame.size.width > frame.size.height ? frame.size.height / 2 : frame.size.width / 2); _arcSize = 2* M_PI; self.showsGlyphBounds = NO; self.showsLineMetrics = NO; self.dimsSubstitutedGlyphs = NO; self.color = color; self.shiftH = self.shiftV = 0.0f; } return self; } 

Depois de muitas tentativas, eu produzo essa modificação para a function PrepareGlyphArcInfo

 // this constants come from a single case ( fontSize = 22 | circle diameter = 250px | lower circle diameter 50px | 0.12f is a proportional acceptable value of 250px diameter | 0.18f is a proportional acceptable value of 50px | 0.035f is a proportional acceptable value of "big" chars #define kReferredCharSpacing 0.12f #define kReferredFontSize 22.f #define kReferredMajorDiameter 250.f #define kReferredMinorDiameter 50.f #define kReferredMinorSpacingFix 0.18f #define kReferredBigCharSpacingFix 0.035f static void PrepareGlyphArcInfo(UIFont* font,CGFloat containerRadius,CTLineRef line, CFIndex glyphCount, GlyphArcInfo *glyphArcInfo, CGFloat arcSizeRad) { NSArray *runArray = (NSArray *)CTLineGetGlyphRuns(line); CGFloat curMaxTypoWidth = 0.f; CGFloat curMinTypoWidth = 0.f; // Examine each run in the line, updating glyphOffset to track how far along the run is in terms of glyphCount. CFIndex glyphOffset = 0; for (id run in runArray) { CFIndex runGlyphCount = CTRunGetGlyphCount((CTRunRef)run); // Ask for the width of each glyph in turn. CFIndex runGlyphIndex = 0; for (; runGlyphIndex < runGlyphCount; runGlyphIndex++) { glyphArcInfo[runGlyphIndex + glyphOffset].width = CTRunGetTypographicBounds((CTRunRef)run, CFRangeMake(runGlyphIndex, 1), NULL, NULL, NULL); if (curMaxTypoWidth < glyphArcInfo[runGlyphIndex + glyphOffset].width) curMaxTypoWidth = glyphArcInfo[runGlyphIndex + glyphOffset].width; if (curMinTypoWidth > glyphArcInfo[runGlyphIndex + glyphOffset].width || curMinTypoWidth == 0) curMinTypoWidth = glyphArcInfo[runGlyphIndex + glyphOffset].width; } glyphOffset += runGlyphCount; } //double lineLength = CTLineGetTypographicBounds(line, NULL, NULL, NULL); glyphArcInfo[0].angle = M_PI_2; // start at the bottom circle CFIndex lineGlyphIndex = 1; // based on font size. (supposing that with fontSize = 22 we could use 0.12) CGFloat maxCharSpacing = font.pointSize * kReferredCharSpacing / kReferredFontSize; // for diameter minor than referred 250 if ((fabsf(containerRadius)*2) < kReferredMajorDiameter) maxCharSpacing = maxCharSpacing + kReferredMinorSpacingFix * kReferredMinorDiameter / (fabsf(containerRadius)*2); CGFloat startAngle = fabsf(glyphArcInfo[0].angle); CGFloat endAngle = startAngle; for (; lineGlyphIndex < glyphCount; lineGlyphIndex++) { CGFloat deltaWidth = curMaxTypoWidth - glyphArcInfo[lineGlyphIndex].width; // fix applied to large characters like uppercase letters or symbols CGFloat bigCharFix = (glyphArcInfo[lineGlyphIndex-1].width == curMaxTypoWidth || (glyphArcInfo[lineGlyphIndex-1].width+2) >= curMaxTypoWidth ? kReferredBigCharSpacingFix : 0 ); glyphArcInfo[lineGlyphIndex].angle = - (maxCharSpacing * (glyphArcInfo[lineGlyphIndex].width + deltaWidth ) / curMaxTypoWidth) - bigCharFix; endAngle += fabsf(glyphArcInfo[lineGlyphIndex].angle); } // center text to bottom glyphArcInfo[0].angle = glyphArcInfo[0].angle + (endAngle - startAngle ) / 2; } 

E mudou o método drawRect: para

 - (void)drawRect:(CGRect)rect { // Don't draw if we don't have a font or string if (self.font == NULL || self.text == NULL) return; // Initialize the text matrix to a known value CGContextRef context = UIGraphicsGetCurrentContext(); //Reset the transformation //Doing this means you have to reset the contentScaleFactor to 1.0 CGAffineTransform t0 = CGContextGetCTM(context); CGFloat xScaleFactor = t0.a > 0 ? t0.a : -t0.a; CGFloat yScaleFactor = t0.d > 0 ? t0.d : -t0.d; t0 = CGAffineTransformInvert(t0); if (xScaleFactor != 1.0 || yScaleFactor != 1.0) t0 = CGAffineTransformScale(t0, xScaleFactor, yScaleFactor); CGContextConcatCTM(context, t0); CGContextSetTextMatrix(context, CGAffineTransformIdentity); NSAttributedString *attStr = self.attributedString; CFAttributedStringRef asr = (CFAttributedStringRef)attStr; CTLineRef line = CTLineCreateWithAttributedString(asr); assert(line != NULL); CFIndex glyphCount = CTLineGetGlyphCount(line); if (glyphCount == 0) { CFRelease(line); return; } GlyphArcInfo * glyphArcInfo = (GlyphArcInfo*)calloc(glyphCount, sizeof(GlyphArcInfo)); PrepareGlyphArcInfo(self.font, self.radius, line, glyphCount, glyphArcInfo, _arcSize); // Move the origin from the lower left of the view nearer to its center. CGContextSaveGState(context); CGContextTranslateCTM(context, CGRectGetMidX(rect)+_shiftH, CGRectGetMidY(rect)+_shiftV); if(ARCVIEW_DEBUG_MODE){ // Stroke the arc in red for verification. CGContextBeginPath(context); CGContextAddArc(context, 0.0, 0.0, self.radius, M_PI_2+_arcSize/2.0, M_PI_2-_arcSize/2.0, 1); CGContextSetRGBStrokeColor(context, 1.0, 0.0, 0.0, 1.0); CGContextStrokePath(context); } // Rotate the context 90 degrees counterclockwise (per 180 degrees) CGContextRotateCTM(context, M_PI_2); // Now for the actual drawing. The angle offset for each glyph relative to the previous glyph has already been calculated; with that information in hand, draw those glyphs overstruck and centered over one another, making sure to rotate the context after each glyph so the glyphs are spread along a semicircular path. CGPoint textPosition = CGPointMake(0.0, self.radius); CGContextSetTextPosition(context, textPosition.x, textPosition.y); CFArrayRef runArray = CTLineGetGlyphRuns(line); CFIndex runCount = CFArrayGetCount(runArray); CFIndex glyphOffset = 0; CFIndex runIndex = 0; for (; runIndex < runCount; runIndex++) { CTRunRef run = (CTRunRef)CFArrayGetValueAtIndex(runArray, runIndex); CFIndex runGlyphCount = CTRunGetGlyphCount(run); Boolean drawSubstitutedGlyphsManually = false; CTFontRef runFont = CFDictionaryGetValue(CTRunGetAttributes(run), kCTFontAttributeName); // Determine if we need to draw substituted glyphs manually. Do so if the runFont is not the same as the overall font. if (self.dimsSubstitutedGlyphs && ![self.font isEqual:(UIFont *)runFont]) { drawSubstitutedGlyphsManually = true; } CFIndex runGlyphIndex = 0; for (; runGlyphIndex < runGlyphCount; runGlyphIndex++) { CFRange glyphRange = CFRangeMake(runGlyphIndex, 1); CGContextRotateCTM(context, -(glyphArcInfo[runGlyphIndex + glyphOffset].angle)); // Center this glyph by moving left by half its width. CGFloat glyphWidth = glyphArcInfo[runGlyphIndex + glyphOffset].width; CGFloat halfGlyphWidth = glyphWidth / 2.0; CGPoint positionForThisGlyph = CGPointMake(textPosition.x - halfGlyphWidth, textPosition.y); // Glyphs are positioned relative to the text position for the line, so offset text position leftwards by this glyph's width in preparation for the next glyph. textPosition.x -= glyphWidth; CGAffineTransform textMatrix = CTRunGetTextMatrix(run); textMatrix.tx = positionForThisGlyph.x; textMatrix.ty = positionForThisGlyph.y; CGContextSetTextMatrix(context, textMatrix); CTRunDraw(run, context, glyphRange); } glyphOffset += runGlyphCount; } CGContextSetFillColorWithColor(context, [UIColor clearColor].CGColor); CGContextSetAlpha(context,0.0); CGContextFillRect(context, rect); CGContextRestoreGState(context); free(glyphArcInfo); CFRelease(line); } 

Como você pode ver, eu uso um método não muito bom para calcular o espaço entre cada caracter (no exemplo original, o espaço entre os caracteres é baseado também no tamanho do arco). De qualquer forma, isso parece funcionar quase bem.

A melhor solução poderia ser curvar um retângulo (assim o texto linear), com esforço gráfico e cálculos menos estranhos.

Isso é o que eu obtive resultado da amostra

Espero que ajude

Este é o meu método para desenhar strings atribuídas curvas em camadas, em um ângulo pré-definido (em radianos):

 [self drawCurvedStringOnLayer:self.layer withAttributedText:incident atAngle:angle withRadius:300]; 

A corda também é automaticamente invertida na área inferior do arco.

insira a descrição da imagem aqui

 - (void)drawCurvedStringOnLayer:(CALayer *)layer withAttributedText:(NSAttributedString *)text atAngle:(float)angle withRadius:(float)radius { // angle in radians CGSize textSize = CGRectIntegral([text boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX) options:(NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading) context:nil]).size; float perimeter = 2 * M_PI * radius; float textAngle = (textSize.width / perimeter * 2 * M_PI); float textRotation; float textDirection; if (angle > degreesToRadians(10) && angle < degreesToRadians(170)) { //bottom string textRotation = 0.5 * M_PI ; textDirection = - 2 * M_PI; angle += textAngle / 2; } else { //top string textRotation = 1.5 * M_PI ; textDirection = 2 * M_PI; angle -= textAngle / 2; } for (int c = 0; c < text.length; c++) { NSRange range = {c, 1}; NSAttributedString* letter = [text attributedSubstringFromRange:range]; CGSize charSize = CGRectIntegral([letter boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX) options:(NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading) context:nil]).size; float letterAngle = ( (charSize.width / perimeter) * textDirection ); float x = radius * cos(angle + (letterAngle/2)); float y = radius * sin(angle + (letterAngle/2)); CATextLayer *singleChar = [self drawTextOnLayer:layer withText:letter frame:CGRectMake(layer.frame.size.width/2 - charSize.width/2 + x, layer.frame.size.height/2 - charSize.height/2 + y, charSize.width, charSize.height) bgColor:nil opacity:1]; singleChar.transform = CATransform3DMakeAffineTransform( CGAffineTransformMakeRotation(angle - textRotation) ); angle += letterAngle; } } - (CATextLayer *)drawTextOnLayer:(CALayer *)layer withText:(NSAttributedString *)text frame:(CGRect)frame bgColor:(UIColor *)bgColor opacity:(float)opacity { CATextLayer *textLayer = [[CATextLayer alloc] init]; [textLayer setFrame:frame]; [textLayer setString:text]; [textLayer setAlignmentMode:kCAAlignmentCenter]; [textLayer setBackgroundColor:bgColor.CGColor]; [textLayer setContentsScale:[UIScreen mainScreen].scale]; [textLayer setOpacity:opacity]; [layer addSublayer:textLayer]; return textLayer; } /** Degrees to Radian **/ #define degreesToRadians(degrees) (( degrees ) / 180.0 * M_PI ) /** Radians to Degrees **/ #define radiansToDegrees(radians) (( radians ) * ( 180.0 / M_PI ) ) 

A solução do Juggleware funciona muito bem, mas parece que não consigo encontrar uma maneira de mudar a direção, ou seja, como eu iria mover o arco do sentido horário para o anti-horário?

Update : After struggling for days with the overcomplicated code in that example, I decided to roll my own. I went for a declarative approach using CATextLayers which are placed on the circle and rotated individually. This way the results were much more simple to achieve. Here’s the core code for you:

 -(void)layoutSublayersOfLayer:(CALayer*)layer { if ( layer != self.layer ) { return; } self.layer.sublayers = nil; LOG( @"Laying out sublayers..." ); CGFloat xcenter = self.frame.size.width / 2; CGFloat ycenter = self.frame.size.height / 2; float angle = arcStart; float angleStep = arcSize / [self.text length]; for ( NSUInteger i = 0; i < [self.text length]; ++i ) { NSRange range = { .location = i, .length = 1 }; NSString* c = [self.text substringWithRange:range]; CGFloat yoffset = sin( DEGREES_TO_RADIANS(angle) ) * radius; CGFloat xoffset = cos( DEGREES_TO_RADIANS(angle) ) * radius; CGFloat rotAngle = 90 - angle; if ( clockwise ) { yoffset = -yoffset; rotAngle = -90 + angle; } CATextLayer* tl = [[CATextLayer alloc] init]; if ( debugMode ) { tl.borderWidth = 1; tl.cornerRadius = 3; tl.borderColor = [UIColor whiteColor].CGColor; } tl.frame = CGRectMake( shiftH + xcenter - xoffset, shiftV + ycenter + yoffset, 20, 20 ); tl.font = self.font.fontName; tl.fontSize = self.font.pointSize; tl.foregroundColor = self.color.CGColor; tl.string = c; tl.alignmentMode = @"center"; tl.transform = CATransform3DMakeAffineTransform( CGAffineTransformMakeRotation( DEGREES_TO_RADIANS(rotAngle) ) ); if ( debugMode ) { CATextLayer* debugLayer = [self debugLayerWithText:[NSString stringWithFormat:@"%u: %.0f°", i, angle]]; debugLayer.transform = CATransform3DMakeAffineTransform( CGAffineTransformMakeRotation( DEGREES_TO_RADIANS(-rotAngle) ) ); [tl addSublayer:debugLayer]; } [self.layer addSublayer:tl]; angle += angleStep; } } 

You can download a sample project that use CoreTextArcView: https://github.com/javenisme/CurvaView

Take the circumference of the inner circle. This is the circle you want the base of the characters to be rendered onto. We’ll call this circumference totalLength .

I assume you have a list of strings to render around the circle in textItems .

Take the width of each string into a textWidths array and distribute them evenly across totalLength , perhaps like this pseudo(pythonish) code:

 block = max(textWidths) assert(block * len(textWidths) <= totalLength) offsets = [(block * i) + ((block-width) / 2) for i, width in enumerate(textWidths)] 

Although better layouts can no doubt be done in the cases where the assert would trigger, all that really matters is that we know where individual words start and end in a known area. To render on a straight line of length totalLength we simply start rendering each block of text at offsets[i] .

To get it onto the circle, we'll map that straight line back onto the circumference. To do that we need to map each pixel along that line onto a position on the circle and an angle. This function converts the offset along that line into an angle (it takes values in the range 0 to totalLength )

 def offsetToAngle(pixel): ratio = pixel / totalLength angle = math.pi * 2 * ratio # cool kids use radians. return angle 

that's your angle. To get a position:

 def angleToPosition(angle, characterWidth): xNorm = math.sin(angle + circleRotation) yNorm = math.cos(angle + circleRotation) halfCWidth = characterWidth / 2 x = xNorm * radius + yNorm * halfCWidth # +y = tangent y = yNorm * radius - xNorm * halfCWidth # -x = tangent again. # translate to the circle centre x += circleCentre.x y += circleCentre.y return x,y 

That's a bit more tricky. This is pretty much the crux of your issues, I'd have thought. The big deal is that you need to offset back along the tangent of the circle to work out the point to start rendering so that the middle of the character hits the radius of the circle. What constitues 'back' depends on your coordinate system. if 0,0 is in the bottom left, then the signs of the tangent components is swapped. I assumed top left.

This is important: I'm also making a big assumption that the text rotation occurs around the bottom left of the glyph. If it doesn't then things will look a bit weird. It will be more noticeable at larger font sizes. There is always a way to compensate for wherever it rotates around, and there's usually a way to tell the system where you want the rotation origin to be (that will be related to the CGContextTranslateCTM call in your code I'd imagine) you'll need to do a small experiment to get characters drawing at a single point rotating around their bottom left.

circleRotation is just an offset so you can rotate the whole circle, rather than having things always be in the same orientation. That's in radians too.

so now for each character in each block of text:

 for text, offset in zip(textItems, offsets): pix = offset # start each block at the offset we calculated earlier. for c in text: cWidth = measureGlyph(c) # choose the circumference location of the middle of the character # this is to match with the tangent calculation of tangentToOffset angle = offsetToAngle(pix + cWidth / 2) x,y = angleToPosition(angle, cWidth) drawGlyph(c, x, y, angle) pix += cWidth # start of next character in circumference space 

That's the concept, anyway.

Referring to Ali Seyman ‘s answer :

You can download a sample project that use CoreTextArcView: https://github.com/javenisme/CurvaView

Add on this method to reduce the view frame size, just like UILabel.

 - (void)sizeToFit{ [super sizeToFit]; CGFloat width = ceilf( fabsf((self.radius*2)) + self.font.lineHeight) + 3.0; CGRect f = self.frame; f.size = CGSizeMake(width,width); self.frame = f; [self setNeedsDisplay]; } 

If anyone could improve on reducing the height as well, welcome to add on.

insira a descrição da imagem aqui

 #import  @interface CircleTextCell : NSCell { } @end #import "CircleTextCell.h" #define PI (3.141592653589793) @implementation CircleTextCell - (void)drawWithFrame: (NSRect)cellFrame inView: (NSView*)controlView { NSAttributedString *str = [self attributedStringValue]; NSSize stringSize = [str size]; NSUInteger chars = [[str string] length]; CGFloat radius = (stringSize.width + 5 * chars) / (2 * PI); CGFloat diameter = 2*radius; NSPoint scale = {1,1}; if (diameter > cellFrame.size.width) { scale.x = cellFrame.size.width / diameter; } if (diameter > cellFrame.size.height) { scale.y = cellFrame.size.height / diameter; } NSAffineTransform *transform = [NSAffineTransform transform]; NSAffineTransformStruct identity = [transform transformStruct]; [transform scaleXBy: scale.x yBy: scale.y]; [transform translateXBy: radius yBy: 0]; [NSGraphicsContext saveGraphicsState]; [transform concat]; NSPoint origin = {0,0}; CGFloat angleScale = 360 / (stringSize.width + (5 * chars)); for (NSUInteger i=0 ; i @class CircleTextCell; @interface CircleTextView : NSView { CircleTextCell *cell; } @end #import "CircleTextView.h" #import "CircleTextCell.h" @implementation CircleTextView - (void)awakeFromNib { NSDictionary *attributes = [NSDictionary dictionaryWithObject: [NSFont fontWithName: @"Zapfino" size:32] forKey: NSFontAttributeName]; NSAttributedString *str = [[NSAttributedString alloc] initWithString: @"Hello World! This is a very long text string that will be wrapped into a circle by a cell drawn in a custom view" attributes: attributes]; cell = [[CircleTextCell alloc] init]; [cell setAttributedStringValue: str]; } - (void)drawRect:(NSRect)rect { [[NSColor whiteColor] setFill]; [NSBezierPath fillRect: rect]; [cell drawWithFrame: [self bounds] inView: self]; } @end 

insira a descrição da imagem aqui that is the best url https://github.com/javenisme/CurvaView to set curve your text:

But as per the the degree wise curve i just update a code little bit and we can set the curve as a degree wise . like 45,60,90 180, 360.

Look at the code : https://github.com/tikamsingh/CurveTextWithAngle

You can take some idea.