UIButton – what is the default image highlight color
Is there any approach how to create from some color (let's say it's [UIColor redColor]) the default highlighted shade of this color (some kind of dark red color in this case).
In my case, I have a UIButton (inside of UIBarButton) and I would like to setup the titleColor for UIControlStateHighlighted state just the same as the default hightlighted color of the UIImage. See the code below:
UIColor *color = [UIColor redColor];
UIColor *highlightedColor = ???;
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setImage:[[UIImage imageNamed:@"back-arrow"] imageWithOverlayColor:color] forState:UIControlStateNormal];
[button setImage:[[UIImage imageNamed:@"back-arrow"] imageWithOverlayColor:highlightedColor] forState:UIControlStateHighlighted];
[button setTitle:title forState:UIControlStateNormal];
[button setTitleColor:color forState:UIControlStateNormal];
[button setTitleColor:highlightedColor forState:UIControlStateHighlighted];
button.imageEdgeInsets = UIEdgeInsetsMake(0.f, -5.f, 0.f, 0.f);
If I don't setup the image/title for the UIControlStateHighlighted state, only the image is highlighted when button is pressed:
You need to merge two kinds of UIColor together, First,you can get the tintColor use :
UIColor *defualtTintColor = self.navigationController.navigationItem.backBarButtonItem.tintColor;
merge redColor and the defualtTintColor together. That is my method,Inelegant, but it works:
UIColor* blend( UIColor* c1, UIColor* c2, float alpha )
{
alpha = MIN( 1.f, MAX( 0.f, alpha ) );
float beta = 1.f - alpha;
CGFloat r1, g1, b1, a1, r2, g2, b2, a2;
[c1 getRed:&r1 green:&g1 blue:&b1 alpha:&a1];
[c2 getRed:&r2 green:&g2 blue:&b2 alpha:&a2];
CGFloat r = r1 * beta + r2 * alpha;
CGFloat g = g1 * beta + g2 * alpha;
CGFloat b = b1 * beta + b2 * alpha;
return [UIColor colorWithRed:r green:g blue:b alpha:1.f];
}
More elegant:
UIColor+Extensions.h:
@interface UIColor (Extensions)
- (UIColor*)blendWithColor:(UIColor*)color2 alpha:(CGFloat)alpha2;
@end
UIColor+Extensions.m:
@implementation UIColor (Extensions)
- (UIColor*)blendWithColor:(UIColor*)color2 alpha:(CGFloat)alpha2
{
alpha2 = MIN( 1.0, MAX( 0.0, alpha2 ) );
CGFloat beta = 1.0 - alpha2;
CGFloat r1, g1, b1, a1, r2, g2, b2, a2;
[self getRed:&r1 green:&g1 blue:&b1 alpha:&a1];
[color2 getRed:&r2 green:&g2 blue:&b2 alpha:&a2];
CGFloat red = r1 * beta + r2 * alpha2;
CGFloat green = g1 * beta + g2 * alpha2;
CGFloat blue = b1 * beta + b2 * alpha2;
CGFloat alpha = a1 * beta + a2 * alpha2;
return [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
}
@end
then you can get highlightedColor:
UIColor *color = [UIColor redColor];
UIColor *defualtTintColor = self.navigationController.navigationItem.backBarButtonItem.tintColor;
UIColor *highlightedColor = [defualtTintColor blendWithColor:color alpha:0.75];
simply add a highlightedImage for button
@implementation UIButton (YASAddition)
- (void)awakeFromNib {
[super awakeFromNib];
UIImage *highlightedImage = [UIImage imageWithColor:[[UIColor colorWithHex:0X1E1E1E] colorWithAlphaComponent:0.2f]];
[self setBackgroundImage:highlightedImage forState:UIControlStateHighlighted];
}
@end
the same for UIBarButtonItem
alpha is the point