html圆角矩形的渐变色,带有渐变颜色的圆角矩形

//

// TeleView.m

//

#import “TeleView.h”

@implementation TeleView

/**** in init methods, set background to transparent,

otherwise, clipping shows a black background ****/

– (id) initWithFrame:(CGRect)frame {

if((self = [super initWithFrame:frame])) {

[self setBackgroundColor:[UIColor colorWithWhite:0.0f alpha:0.0f]];

}

return self;

}

– (void) clipCornersToOvalWidth:(float)ovalWidth height:(float)ovalHeight

{

float fw, fh;

CGContextRef context = UIGraphicsGetCurrentContext();

CGRect rect = CGRectMake(0.0f, 0.0f, self.frame.size.width, self.frame.size.height);

if (ovalWidth == 0 || ovalHeight == 0) {

CGContextAddRect(context, rect);

return;

}

CGContextSaveGState(context);

CGContextTranslateCTM (context, CGRectGetMinX(rect), CGRectGetMinY(rect));

CGContextScaleCTM (context, ovalWidth, ovalHeight);

fw = CGRectGetWidth (rect) / ovalWidth;

fh = CGRectGetHeight (rect) / ovalHeight;

CGContextMoveToPoint(context, fw, fh/2);

CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1);

CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1);

CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1);

CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1);

CGContextClosePath(context);

CGContextRestoreGState(context);

}

-(void)drawRect:(CGRect)rect {

CGContextRef currentContext = UIGraphicsGetCurrentContext();

/**** here is what I modified. ****/

[self clipCornersToOvalWidth:20.0f height:20.0f];

CGContextClip(currentContext);

/**** below this is your own code ****/

CGGradientRef glossGradient;

CGColorSpaceRef rgbColorspace;

size_t num_locations = 2;

CGFloat locations[2] = { 0.0, 1.0 };

CGFloat components[8] = { 1.0, 0.0, 0.0, 0.60, // Start color

0.0, 1.0, 0.0, 0.40 }; // 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), CGRectGetMaxY(currentBounds));

CGContextDrawLinearGradient(currentContext, glossGradient, topCenter, midCenter, 0);

CGGradientRelease(glossGradient);

CGColorSpaceRelease(rgbColorspace);

}

@end