Muchas gracias a todos los que publicaron su código. Esto es muy útil.
Derivé una solución similar para cambiar el color de resaltado de las celdas de vista de tabla agrupadas. Básicamente, el selectedBackgroundView de UITableViewCell (no el backgroundView). Que incluso en iPhone OS 3.0 todavía necesita esta solución PITA, por lo que puedo decir ...
El siguiente código tiene los cambios para representar el resaltado con un degradado en lugar de un color sólido. También se elimina el renderizado del borde. Disfrutar.
//
// CSCustomCellBackgroundView.h
//
#import <UIKit/UIKit.h>
typedef enum
{
CustomCellBackgroundViewPositionTop,
CustomCellBackgroundViewPositionMiddle,
CustomCellBackgroundViewPositionBottom,
CustomCellBackgroundViewPositionSingle,
CustomCellBackgroundViewPositionPlain
} CustomCellBackgroundViewPosition;
@interface CSCustomCellBackgroundView : UIView
{
CustomCellBackgroundViewPosition position;
CGGradientRef gradient;
}
@property(nonatomic) CustomCellBackgroundViewPosition position;
@end
//
// CSCustomCellBackgroundView.m
//
#import "CSCustomCellBackgroundView.h"
#define ROUND_SIZE 10
static void addRoundedRectToPath(CGContextRef context, CGRect rect,
float ovalWidth,float ovalHeight);
@implementation CSCustomCellBackgroundView
@synthesize position;
- (BOOL) isOpaque
{
return NO;
}
- (id)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame])
{
// Initialization code
const float* topCol = CGColorGetComponents([[UIColor redColor] CGColor]);
const float* bottomCol = CGColorGetComponents([[UIColor blueColor] CGColor]);
CGColorSpaceRef rgb = CGColorSpaceCreateDeviceRGB();
/*
CGFloat colors[] =
{
5.0 / 255.0, 140.0 / 255.0, 245.0 / 255.0, 1.00,
1.0 / 255.0, 93.0 / 255.0, 230.0 / 255.0, 1.00,
};*/
CGFloat colors[]=
{
topCol[0], topCol[1], topCol[2], topCol[3],
bottomCol[0], bottomCol[1], bottomCol[2], bottomCol[3]
};
gradient = CGGradientCreateWithColorComponents(rgb, colors, NULL, sizeof(colors)/(sizeof(colors[0])*4));
CGColorSpaceRelease(rgb);
}
return self;
}
-(void)drawRect:(CGRect)rect
{
// Drawing code
CGContextRef c = UIGraphicsGetCurrentContext();
if (position == CustomCellBackgroundViewPositionTop)
{
CGFloat minx = CGRectGetMinX(rect) , midx = CGRectGetMidX(rect), maxx = CGRectGetMaxX(rect) ;
CGFloat miny = CGRectGetMinY(rect) , maxy = CGRectGetMaxY(rect) ;
minx = minx + 1;
miny = miny + 1;
maxx = maxx - 1;
maxy = maxy ;
CGContextMoveToPoint(c, minx, maxy);
CGContextAddArcToPoint(c, minx, miny, midx, miny, ROUND_SIZE);
CGContextAddArcToPoint(c, maxx, miny, maxx, maxy, ROUND_SIZE);
CGContextAddLineToPoint(c, maxx, maxy);
// Close the path
CGContextClosePath(c);
CGContextSaveGState(c);
CGContextClip(c);
CGContextDrawLinearGradient(c, gradient, CGPointMake(minx,miny), CGPointMake(minx,maxy), kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
CGContextRestoreGState(c);
return;
}
else if (position == CustomCellBackgroundViewPositionBottom)
{
CGFloat minx = CGRectGetMinX(rect) , midx = CGRectGetMidX(rect), maxx = CGRectGetMaxX(rect) ;
CGFloat miny = CGRectGetMinY(rect) , maxy = CGRectGetMaxY(rect) ;
minx = minx + 1;
miny = miny + 1;
maxx = maxx - 1;
maxy = maxy - 1;
CGContextMoveToPoint(c, minx, miny);
CGContextAddArcToPoint(c, minx, maxy, midx, maxy, ROUND_SIZE);
CGContextAddArcToPoint(c, maxx, maxy, maxx, miny, ROUND_SIZE);
CGContextAddLineToPoint(c, maxx, miny);
// Close the path
CGContextClosePath(c);
CGContextSaveGState(c);
CGContextClip(c);
CGContextDrawLinearGradient(c, gradient, CGPointMake(minx,miny), CGPointMake(minx,maxy), kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
CGContextRestoreGState(c);
return;
}
else if (position == CustomCellBackgroundViewPositionMiddle)
{
CGFloat minx = CGRectGetMinX(rect) , maxx = CGRectGetMaxX(rect) ;
CGFloat miny = CGRectGetMinY(rect) , maxy = CGRectGetMaxY(rect) ;
minx = minx + 1;
miny = miny + 1;
maxx = maxx - 1;
maxy = maxy ;
CGContextMoveToPoint(c, minx, miny);
CGContextAddLineToPoint(c, maxx, miny);
CGContextAddLineToPoint(c, maxx, maxy);
CGContextAddLineToPoint(c, minx, maxy);
// Close the path
CGContextClosePath(c);
CGContextSaveGState(c);
CGContextClip(c);
CGContextDrawLinearGradient(c, gradient, CGPointMake(minx,miny), CGPointMake(minx,maxy), kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
CGContextRestoreGState(c);
return;
}
else if (position == CustomCellBackgroundViewPositionSingle)
{
CGFloat minx = CGRectGetMinX(rect) , midx = CGRectGetMidX(rect), maxx = CGRectGetMaxX(rect) ;
CGFloat miny = CGRectGetMinY(rect) , midy = CGRectGetMidY(rect) , maxy = CGRectGetMaxY(rect) ;
minx = minx + 1;
miny = miny + 1;
maxx = maxx - 1;
maxy = maxy - 1;
CGContextMoveToPoint(c, minx, midy);
CGContextAddArcToPoint(c, minx, miny, midx, miny, ROUND_SIZE);
CGContextAddArcToPoint(c, maxx, miny, maxx, midy, ROUND_SIZE);
CGContextAddArcToPoint(c, maxx, maxy, midx, maxy, ROUND_SIZE);
CGContextAddArcToPoint(c, minx, maxy, minx, midy, ROUND_SIZE);
// Close the path
CGContextClosePath(c);
CGContextSaveGState(c);
CGContextClip(c);
CGContextDrawLinearGradient(c, gradient, CGPointMake(minx,miny), CGPointMake(minx,maxy), kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
CGContextRestoreGState(c);
return;
}
else if (position == CustomCellBackgroundViewPositionPlain) {
CGFloat minx = CGRectGetMinX(rect);
CGFloat miny = CGRectGetMinY(rect), maxy = CGRectGetMaxY(rect) ;
CGContextDrawLinearGradient(c, gradient, CGPointMake(minx,miny), CGPointMake(minx,maxy), kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
return;
}
}
- (void)dealloc
{
CGGradientRelease(gradient);
[super dealloc];
}
- (void) setPosition:(CustomCellBackgroundViewPosition)inPosition
{
if(position != inPosition)
{
position = inPosition;
[self setNeedsDisplay];
}
}
@end
static void addRoundedRectToPath(CGContextRef context, CGRect rect,
float ovalWidth,float ovalHeight)
{
float fw, fh;
if (ovalWidth == 0 || ovalHeight == 0) {// 1
CGContextAddRect(context, rect);
return;
}
CGContextSaveGState(context);// 2
CGContextTranslateCTM (context, CGRectGetMinX(rect),// 3
CGRectGetMinY(rect));
CGContextScaleCTM (context, ovalWidth, ovalHeight);// 4
fw = CGRectGetWidth (rect) / ovalWidth;// 5
fh = CGRectGetHeight (rect) / ovalHeight;// 6
CGContextMoveToPoint(context, fw, fh/2); // 7
CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1);// 8
CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1);// 9
CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1);// 10
CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1); // 11
CGContextClosePath(context);// 12
CGContextRestoreGState(context);// 13
}