Interface Builder Designable Custom View

MJPlaceholderView.h

#import <UIKit/UIKit.h>

// IB_DESIGNABLE means that the view will be
// rendered live in Interface Builder.

IB_DESIGNABLE
@interface MJPlaceholderView : UIView

// IBInspectable means that the property
// will be editable in the Attributes
// inspector panel in Interface Builder.

@property (nonatomic, copy) IBInspectable NSString *text;
@property (nonatomic, assign) IBInspectable CGFloat textSize;
@property (nonatomic, strong) IBInspectable UIColor *textColor;

@property (nonatomic, strong) IBInspectable UIColor *fillColor;

@property (nonatomic, assign) IBInspectable CGFloat cornerRadius;

@end

MJPlaceholderView.m

#import "MJPlaceholderView.h"

@implementation MJPlaceholderView

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self != nil) {
        // This is run when the view is created
        // in Interface Builder.
    }
    
    return self;
}

- (void)prepareForInterfaceBuilder {
    [super prepareForInterfaceBuilder];
    /*
     * If you need to create code for a custom view that runs
     * only in Interface Builder, call that code from the method
     * prepareForInterfaceBuilder. For example, while designing
     * an app that uses the iPhone camera, you might want to draw
     * an image that represents what the camera might capture.
     * Although it’s compiled for runtime, code called from
     * prepareForInterfaceBuilder never gets called except by
     * Interface Builder at design time.
     */
}

- (CGFloat)cornerRadius {
    return self.layer.cornerRadius;
}

- (void)setCornerRadius:(CGFloat)cornerRadius {
    self.layer.cornerRadius = cornerRadius;
    self.layer.masksToBounds = cornerRadius > 0.0f;
}

- (void)drawRect:(CGRect)rect {
    
#if TARGET_INTERFACE_BUILDER
    // This is only compiled for the interface builder.
#else
    // This is only compiled for runtime.
#endif
    
    [(_fillColor ?: [UIColor magentaColor]) set];
    UIRectFill(self.bounds);
    
    NSString *size = [NSString stringWithFormat:@"%u x %u",
                        (uint32_t)self.bounds.size.width,
                        (uint32_t)self.bounds.size.height];

    [self drawCenteredText:size verticalOffsetInMultipleOfHeight:0.5f];
    [self drawCenteredText:(self.text ?: @"Placeholder") verticalOffsetInMultipleOfHeight:-0.5f];
}

- (void)drawCenteredText:(NSString *)text verticalOffsetInMultipleOfHeight:(CGFloat)offsetMultiple {
    CGFloat fontSize = _textSize > 1.0f ? _textSize : 16.0f;
    NSDictionary *attributes = @{NSFontAttributeName: [UIFont fontWithName:@"HelveticaNeue-Light" size:fontSize],
                                 NSForegroundColorAttributeName:_textColor ?: [UIColor blackColor]};
    CGSize size = [text sizeWithAttributes:attributes];
    CGRect rect = self.bounds;
    CGRect r = CGRectMake(rect.origin.x + (rect.size.width - size.width) / 2.0,
                          rect.origin.y + (rect.size.height - size.height) / 2.0 + size.height * offsetMultiple,
                          rect.size.width,
                          size.height);
    [text drawInRect:r withAttributes:attributes];
}

@end