Gradients on UIView and UILabels On iPhone

Question

Possible Duplicate    Manually drawing a gradient in iPhone apps        My application needs to display text in either a UIView or UILabel but the back ground must be a gradient as opposed to a true UIColor  Using a graphics program to create desired look is no good as the text may vary depending on data returned from a server   Does anyone know the quickest way to tackle this  Your thoughts are greatly appreciated

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Note  The results below apply to older versions of iOS  but when testing on iOS 13 the stepping doesn t occur  I don t know for which version of iOS the stepping was removed     When using CAGradientLayer  as opposed to CGGradient  the gradient is not smooth  but has noticeable stepping to it  See    To get more attractive results it is better to use CGGradient

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You could also use a graphic image one pixel wide as the gradient  and set the view property to expand the graphic to fill the view  assuming you are thinking of a simple linear gradient and not some kind of radial graphic

User · Answer

You could also use a graphic image one pixel wide as the gradient  and set the view property to expand the graphic to fill the view  assuming you are thinking of a simple linear gradient and not some kind of radial graphic

User · Answer

You can use Core Graphics to draw the gradient  as pointed to in Mike s response   As a more detailed example  you could create a UIView subclass to use as a background for your UILabel   In that UIView subclass  override the drawRect  method and insert code similar to the following   -  void drawRect  CGRect rect        CGContextRef currentContext   UIGraphicsGetCurrentContext         CGGradientRef glossGradient      CGColorSpaceRef rgbColorspace      size t num locations   2      CGFloat locations 2      0 0  1 0        CGFloat components 8      1 0  1 0  1 0  0 35      Start color          1 0  1 0  1 0  0 06       End color      rgbColorspace   CGColorSpaceCreateDeviceRGB        glossGradient   CGGradientCreateWithColorComponents rgbColorspace  components  locations  num locations        CGRect currentBounds   self bounds      CGPoint topCenter   CGPointMake CGRectGetMidX currentBounds   0 0f       CGPoint midCenter   CGPointMake CGRectGetMidX currentBounds   CGRectGetMidY currentBounds        CGContextDrawLinearGradient currentContext  glossGradient  topCenter  midCenter  0        CGGradientRelease glossGradient       CGColorSpaceRelease rgbColorspace        This particular example creates a white  glossy-style gradient that is drawn from the top of the UIView to its vertical center   You can set the UIView s backgroundColor to whatever you like and this gloss will be drawn on top of that color   You can also draw a radial gradient using the CGContextDrawRadialGradient function   You just need to size this UIView appropriately and add your UILabel as a subview of it to get the effect you desire   EDIT  4 23 2009   Per St3fan s suggestion  I have replaced the view s frame with its bounds in the code   This corrects for the case when the view s origin is not  0 0

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You can use Core Graphics to draw the gradient  as pointed to in Mike s response   As a more detailed example  you could create a UIView subclass to use as a background for your UILabel   In that UIView subclass  override the drawRect  method and insert code similar to the following   -  void drawRect  CGRect rect        CGContextRef currentContext   UIGraphicsGetCurrentContext         CGGradientRef glossGradient      CGColorSpaceRef rgbColorspace      size t num locations   2      CGFloat locations 2      0 0  1 0        CGFloat components 8      1 0  1 0  1 0  0 35      Start color          1 0  1 0  1 0  0 06       End color      rgbColorspace   CGColorSpaceCreateDeviceRGB        glossGradient   CGGradientCreateWithColorComponents rgbColorspace  components  locations  num locations        CGRect currentBounds   self bounds      CGPoint topCenter   CGPointMake CGRectGetMidX currentBounds   0 0f       CGPoint midCenter   CGPointMake CGRectGetMidX currentBounds   CGRectGetMidY currentBounds        CGContextDrawLinearGradient currentContext  glossGradient  topCenter  midCenter  0        CGGradientRelease glossGradient       CGColorSpaceRelease rgbColorspace        This particular example creates a white  glossy-style gradient that is drawn from the top of the UIView to its vertical center   You can set the UIView s backgroundColor to whatever you like and this gloss will be drawn on top of that color   You can also draw a radial gradient using the CGContextDrawRadialGradient function   You just need to size this UIView appropriately and add your UILabel as a subview of it to get the effect you desire   EDIT  4 23 2009   Per St3fan s suggestion  I have replaced the view s frame with its bounds in the code   This corrects for the case when the view s origin is not  0 0

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Mirko Froehlich s answer worked for me  except when i wanted to use custom colors  The trick is to specify UI color with Hue  saturation and brightness instead of RGB   CAGradientLayer  gradient    CAGradientLayer layer   gradient frame   myView bounds  UIColor  startColour    UIColor colorWithHue  580555 saturation 0 31 brightness 0 90 alpha 1 0   UIColor  endColour    UIColor colorWithHue  58333 saturation 0 50 brightness 0 62 alpha 1 0   gradient colors    NSArray arrayWithObjects  id  startColour CGColor    id  endColour CGColor   nil    myView layer insertSublayer gradient atIndex 0     To get the Hue  Saturation and Brightness of a color  use the in built xcode color picker and go to the HSB tab  Hue is measured in degrees in this view  so divide the value by 360 to get the value you will want to enter in code

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This is what I got working- set UIButton in xCode s IB to transparent clear  and no bg image   UIColor  pinkDarkOp    UIColor colorWithRed 0 9f green 0 53f blue 0 69f alpha 1 0   UIColor  pinkLightOp    UIColor colorWithRed 0 79f green 0 45f blue 0 57f alpha 1 0    CAGradientLayer  gradient    CAGradientLayer layer   gradient frame     shareWordButton layer  bounds   gradient cornerRadius   7  gradient colors    NSArray arrayWithObjects                      id pinkDarkOp CGColor                      id pinkLightOp CGColor                     nil   gradient locations    NSArray arrayWithObjects                         NSNumber numberWithFloat 0 0f                          NSNumber numberWithFloat 0 7                         nil      recordButton layer  insertSublayer gradient atIndex 0

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This is what I got working- set UIButton in xCode s IB to transparent clear  and no bg image   UIColor  pinkDarkOp    UIColor colorWithRed 0 9f green 0 53f blue 0 69f alpha 1 0   UIColor  pinkLightOp    UIColor colorWithRed 0 79f green 0 45f blue 0 57f alpha 1 0    CAGradientLayer  gradient    CAGradientLayer layer   gradient frame     shareWordButton layer  bounds   gradient cornerRadius   7  gradient colors    NSArray arrayWithObjects                      id pinkDarkOp CGColor                      id pinkLightOp CGColor                     nil   gradient locations    NSArray arrayWithObjects                         NSNumber numberWithFloat 0 0f                          NSNumber numberWithFloat 0 7                         nil      recordButton layer  insertSublayer gradient atIndex 0

User · Answer

You can use Core Graphics to draw the gradient  as pointed to in Mike s response   As a more detailed example  you could create a UIView subclass to use as a background for your UILabel   In that UIView subclass  override the drawRect  method and insert code similar to the following   -  void drawRect  CGRect rect        CGContextRef currentContext   UIGraphicsGetCurrentContext         CGGradientRef glossGradient      CGColorSpaceRef rgbColorspace      size t num locations   2      CGFloat locations 2      0 0  1 0        CGFloat components 8      1 0  1 0  1 0  0 35      Start color          1 0  1 0  1 0  0 06       End color      rgbColorspace   CGColorSpaceCreateDeviceRGB        glossGradient   CGGradientCreateWithColorComponents rgbColorspace  components  locations  num locations        CGRect currentBounds   self bounds      CGPoint topCenter   CGPointMake CGRectGetMidX currentBounds   0 0f       CGPoint midCenter   CGPointMake CGRectGetMidX currentBounds   CGRectGetMidY currentBounds        CGContextDrawLinearGradient currentContext  glossGradient  topCenter  midCenter  0        CGGradientRelease glossGradient       CGColorSpaceRelease rgbColorspace        This particular example creates a white  glossy-style gradient that is drawn from the top of the UIView to its vertical center   You can set the UIView s backgroundColor to whatever you like and this gloss will be drawn on top of that color   You can also draw a radial gradient using the CGContextDrawRadialGradient function   You just need to size this UIView appropriately and add your UILabel as a subview of it to get the effect you desire   EDIT  4 23 2009   Per St3fan s suggestion  I have replaced the view s frame with its bounds in the code   This corrects for the case when the view s origin is not  0 0

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I realize this is an older thread  but for future reference   As of iPhone SDK 3 0  custom gradients can be implemented very easily  without subclassing or images  by using the new CAGradientLayer    UIView  view      UIView alloc  initWithFrame CGRectMake 0  0  320  100   autorelease    CAGradientLayer  gradient    CAGradientLayer layer    gradient frame   view bounds   gradient colors    NSArray arrayWithObjects  id   UIColor blackColor  CGColor    id   UIColor whiteColor  CGColor   nil     view layer insertSublayer gradient atIndex 0     Take a look at the CAGradientLayer docs  You can optionally specify start and end points  in case you don t want a linear gradient that goes straight from the top to the bottom   or even specific locations that map to each of the colors

User · Answer

You could also use a graphic image one pixel wide as the gradient  and set the view property to expand the graphic to fill the view  assuming you are thinking of a simple linear gradient and not some kind of radial graphic

User · Answer

I realize this is an older thread  but for future reference   As of iPhone SDK 3 0  custom gradients can be implemented very easily  without subclassing or images  by using the new CAGradientLayer    UIView  view      UIView alloc  initWithFrame CGRectMake 0  0  320  100   autorelease    CAGradientLayer  gradient    CAGradientLayer layer    gradient frame   view bounds   gradient colors    NSArray arrayWithObjects  id   UIColor blackColor  CGColor    id   UIColor whiteColor  CGColor   nil     view layer insertSublayer gradient atIndex 0     Take a look at the CAGradientLayer docs  You can optionally specify start and end points  in case you don t want a linear gradient that goes straight from the top to the bottom   or even specific locations that map to each of the colors

User · Answer

You could also use a graphic image one pixel wide as the gradient  and set the view property to expand the graphic to fill the view  assuming you are thinking of a simple linear gradient and not some kind of radial graphic

User · Answer

I achieve this in a view with a subview that is an UIImageView   The image the ImageView is pointing to is a gradient   Then I set a background color in the UIView  and I have a colored gradient view   Next I use the view as I need to and everything I draw will be under this gradient view   By adding a second view on top of the ImageView  you can have some options whether your drawing will be below or above the gradient

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I achieve this in a view with a subview that is an UIImageView   The image the ImageView is pointing to is a gradient   Then I set a background color in the UIView  and I have a colored gradient view   Next I use the view as I need to and everything I draw will be under this gradient view   By adding a second view on top of the ImageView  you can have some options whether your drawing will be below or above the gradient

User · Answer

You can use Core Graphics to draw the gradient  as pointed to in Mike s response   As a more detailed example  you could create a UIView subclass to use as a background for your UILabel   In that UIView subclass  override the drawRect  method and insert code similar to the following   -  void drawRect  CGRect rect        CGContextRef currentContext   UIGraphicsGetCurrentContext         CGGradientRef glossGradient      CGColorSpaceRef rgbColorspace      size t num locations   2      CGFloat locations 2      0 0  1 0        CGFloat components 8      1 0  1 0  1 0  0 35      Start color          1 0  1 0  1 0  0 06       End color      rgbColorspace   CGColorSpaceCreateDeviceRGB        glossGradient   CGGradientCreateWithColorComponents rgbColorspace  components  locations  num locations        CGRect currentBounds   self bounds      CGPoint topCenter   CGPointMake CGRectGetMidX currentBounds   0 0f       CGPoint midCenter   CGPointMake CGRectGetMidX currentBounds   CGRectGetMidY currentBounds        CGContextDrawLinearGradient currentContext  glossGradient  topCenter  midCenter  0        CGGradientRelease glossGradient       CGColorSpaceRelease rgbColorspace        This particular example creates a white  glossy-style gradient that is drawn from the top of the UIView to its vertical center   You can set the UIView s backgroundColor to whatever you like and this gloss will be drawn on top of that color   You can also draw a radial gradient using the CGContextDrawRadialGradient function   You just need to size this UIView appropriately and add your UILabel as a subview of it to get the effect you desire   EDIT  4 23 2009   Per St3fan s suggestion  I have replaced the view s frame with its bounds in the code   This corrects for the case when the view s origin is not  0 0

User · Answer

Note  The results below apply to older versions of iOS  but when testing on iOS 13 the stepping doesn t occur  I don t know for which version of iOS the stepping was removed     When using CAGradientLayer  as opposed to CGGradient  the gradient is not smooth  but has noticeable stepping to it  See    To get more attractive results it is better to use CGGradient

User · Answer

Mirko Froehlich s answer worked for me  except when i wanted to use custom colors  The trick is to specify UI color with Hue  saturation and brightness instead of RGB   CAGradientLayer  gradient    CAGradientLayer layer   gradient frame   myView bounds  UIColor  startColour    UIColor colorWithHue  580555 saturation 0 31 brightness 0 90 alpha 1 0   UIColor  endColour    UIColor colorWithHue  58333 saturation 0 50 brightness 0 62 alpha 1 0   gradient colors    NSArray arrayWithObjects  id  startColour CGColor    id  endColour CGColor   nil    myView layer insertSublayer gradient atIndex 0     To get the Hue  Saturation and Brightness of a color  use the in built xcode color picker and go to the HSB tab  Hue is measured in degrees in this view  so divide the value by 360 to get the value you will want to enter in code

[iphone] Gradients on UIView and UILabels On iPhone

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