Color gradient for ios 2D plotting

Color gradient for ios 2D plotting
Color gradient for ios 2D plotting
Color Space cmyk Printing Industry RGB gradient color: linear gradient, ring gradient linear gradient: the gradient area is the current context, perpendicular to startPoint <-> endPoint line segment, and the linear ring gradient at the intersection of this line segment:
Corefoundation (c) -- foundation (oc) Conversion forced conversion: __bridge id (type)
/*****/Automatic reference count
Save the drawn image and create the image context -- get the canvas --...... -- Get image -- Save image -- compress the image to an end: png (lossless compression) jpg (lossy compression)

# Import "LinearGradient. h"

 

@ Implementation LinearGradient

// Linear gradient

 

-(Void) drawRect :( CGRect) rect {

CGContextRef context = UIGraphicsGetCurrentContext ();

 

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB ();

// Color component Representation

CGFloat components [] = {1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 1.0, 0.0 };

// Color position

CGFloat locations [] = {1.0, 0.0, 0.5 };

CGGradientRef gradient = CGGradientCreateWithColorComponents (colorSpace, components, locations, 3 );

// The gradient area is the current context, perpendicular to the startPoint <-> endPoint line segment, and the line that the line segment Intersection

CGContextDrawLinearGradient (context, gradient, CGPointMake (100, 0), CGPointMake (200, 0), 0 );

 

CGFloat locations2 [] = {0.4, 1.0 };

CGGradientRef gradient2 = CGGradientCreateWithColorComponents (colorSpace, components, locations2, 2 );

// The gradient area is the current context, perpendicular to the startPoint <-> endPoint line segment, and the line that the line segment Intersection

CGContextDrawLinearGradient (context, gradient2, CGPointMake (210, 0), CGPointMake (310, 0), 0 );

}

 

@ End

# Import "RadialGradientView. h"

 

@ Implementation RadialGradientView

// Ring gradient

-(Void) drawRect :( CGRect) rect {

CGContextRef context = UIGraphicsGetCurrentContext ();

 

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB ();

 

NSArray * array = @ [(_ bridge id) [UIColor redColor]. CGColor, (_ bridge id) [UIColor blueColor]. CGColor, (_ bridge id) [UIColor purpleColor]. CGColor];

CGFloat locations [] = {0.0, 0.5, 1.0 };

CGGradientRef gradient = CGGradientCreateWithColors (colorSpace, (_ bridge CFArrayRef) array, locations );

CGContextDrawRadialGradient (context, gradient, CGPointMake (200,200), 0, CGPointMake (150,200), 100, 0 );

}

 

@ End

// Save the drawn Image

# Import "ViewController. h"

 

@ Interface ViewController ()

 

@ End

 

@ Implementation ViewController

 

-(Void) viewDidLoad {

[Super viewDidLoad];

 

UIGraphicsBeginImageContext (CGSizeMake (200,200 ));

 

CGContextRef context = UIGraphicsGetCurrentContext ();

 

CGContextSetFillColorWithColor (context, [UIColor yellowColor]. CGColor );

 

CGContextFillRect (context, CGRectMake (0, 0,100,100 ));

 

UIImage * image = UIGraphicsGetImageFromCurrentImageContext ();

NSData * data = UIImageJPEGRepresentation (image, 1.0 );

// NSData * data = UIImagePNGRepresentation (image );

[Data writeToFile: @ "/Users/apple/desktop/image.jpg" atomically: YES];

UIGraphicsEndImageContext ();

 

}

 

-(Void) didReceiveMemoryWarning {

 

[Super didReceiveMemoryWarning];

 

}

 

@ End