Muito obrigado a todos que postaram seu código. Isso é muito útil.
Eu deduzi uma solução semelhante para alterar a cor de realce para células de visualização de tabela agrupadas. Basicamente, o selectedBackgroundView do UITableViewCell (não o backgroundView). Que mesmo no iPhone OS 3.0 ainda precisa desta solução PITA, pelo que eu posso dizer ...
O código abaixo tem as alterações para renderizar o destaque com um gradiente em vez de uma cor sólida. Além disso, a renderização da borda é removida. Aproveitar.
//
// 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
}