封装CoreGraphics的API简化绘图操作

//
//  CGContextObject.h
//  DrawRect
//
//  Created by YouXianMing on 15/7/2.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <CoreGraphics/CoreGraphics.h>
#import "RGBColor.h"
@class CGContextObject;


typedef void(^CGContextObjectDrawBlock_t)(CGContextObject *contextObject);


@interface CGContextObject : NSObject

/**
 *  操作句柄
 */
@property (nonatomic)          CGContextRef   context;

/**
 *  线头样式
 */
@property (nonatomic)          CGLineCap      lineCap;

/**
 *  线条宽度
 */
@property (nonatomic)          CGFloat        lineWidth;

/**
 *  线条颜色
 */
@property (nonatomic, strong)  RGBColor      *strokeColor;

/**
 *  填充颜色
 */
@property (nonatomic, strong)  RGBColor      *fillColor;

/**
 *  由context进行初始化
 *
 *  @param context 绘制句柄
 *
 *  @return 绘制对象
 */
- (instancetype)initWithCGContext:(CGContextRef)context;

#pragma mark -
/**
 *  开始path
 */
- (void)beginPath;

/**
 *  关闭path
 */
- (void)closePath;

/**
 *  线条绘制
 */
- (void)strokePath;

/**
 *  填充绘制
 */
- (void)fillPath;

/**
 *  线条绘制 + 填充绘制
 */
- (void)strokeAndFillPath;

/**
 *  绘制线条用block (beginPath + closePath + 你绘制的代码 + strokePath)
 *
 *  @param block 绘制用block
 */
- (void)drawStrokeBlock:(CGContextObjectDrawBlock_t)block;

/**
 *  填充区域用block (beginPath + closePath + 你绘制的代码 + fillPath)
 *
 *  @param block 填充用block
 */
- (void)drawFillBlock:(CGContextObjectDrawBlock_t)block;

/**
 *  绘制加填充
 *
 *  @param block 绘制加填充用block
 */
- (void)drawStrokeAndFillBlock:(CGContextObjectDrawBlock_t)block;

#pragma mark - 

/**
 *  将当前设置存取到栈区中(入栈操作)
 */
- (void)saveStateToStack;

/**
 *  从栈区中取出之前保存的设置(出栈操作)
 */
- (void)restoreStateFromStack;

#pragma mark -
/**
 *  移动到起始点
 *
 *  @param point 起始点
 */
- (void)moveToStartPoint:(CGPoint)point;

/**
 *  添加一个点(与上一个点直线相连)
 *
 *  @param point 点
 */
- (void)addLineToPoint:(CGPoint)point;

#pragma mark - 
/**
 *  添加一个矩形
 *
 *  @param rect
 */
- (void)addRect:(CGRect)rect;

/**
 *  在给定的矩形中绘制椭圆
 *
 *  @param rect
 */
- (void)addEllipseInRect:(CGRect)rect;

/**
 *  将string绘制在指定的点上
 *
 *  @param string     字符串
 *  @param point      点
 *  @param attributes 富文本
 */
- (void)drawString:(NSString *)string atPoint:(CGPoint)point withAttributes:(NSDictionary *)attributes;

@end

//
//  CGContextObject.m
//  DrawRect
//
//  Created by YouXianMing on 15/7/2.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import "CGContextObject.h"

@interface CGContextObject ()

@end

@implementation CGContextObject

- (instancetype)initWithCGContext:(CGContextRef)context {
    
    self = [super init];
    if (self) {
        
        self.context = context;
    }
    
    return self;
}

- (void)moveToStartPoint:(CGPoint)point {
    
    if (_context) {
        CGContextMoveToPoint(_context, point.x, point.y);
    }
}

- (void)addLineToPoint:(CGPoint)point {
    
    if (_context) {
        CGContextAddLineToPoint(_context, point.x, point.y);
    }
}

- (void)addRect:(CGRect)rect {

    if (_context) {
        CGContextAddRect(_context, rect);
    }
}

- (void)addEllipseInRect:(CGRect)rect {
    
    if (_context) {
        CGContextAddEllipseInRect(_context, rect);
    }
}

- (void)drawString:(NSString *)string atPoint:(CGPoint)point withAttributes:(NSDictionary *)attributes {

    [string drawAtPoint:point withAttributes:attributes];
}

- (void)beginPath {
    
    if (_context) {
        CGContextBeginPath(_context);
    }
}

- (void)closePath {

    if (_context) {
        CGContextClosePath(_context);
    }
}

- (void)strokePath {

    if (_context) {
        CGContextStrokePath(_context);
    }
}

- (void)fillPath {

    if (_context) {
        CGContextFillPath(_context);
    }
}

- (void)strokeAndFillPath {

    if (_context) {
        CGContextDrawPath(_context, kCGPathFillStroke);
    }
}

- (void)drawStrokeBlock:(CGContextObjectDrawBlock_t)block {

    [self beginPath];
    
    __weak CGContextObject *weakSelf = self;
    
    block(weakSelf);
    
    [self closePath];
    
    [self strokePath];
}

- (void)drawFillBlock:(CGContextObjectDrawBlock_t)block {
    
    [self beginPath];
    
    __weak CGContextObject *weakSelf = self;
    
    block(weakSelf);
    
    [self closePath];
    
    [self fillPath];
}

- (void)drawStrokeAndFillBlock:(CGContextObjectDrawBlock_t)block {

    [self beginPath];
    
    __weak CGContextObject *weakSelf = self;
    
    block(weakSelf);
    
    [self closePath];
    
    [self strokeAndFillPath];
}

- (void)saveStateToStack {
    
    if (_context) {
        CGContextSaveGState(_context);
    }
}

- (void)restoreStateFromStack {
    
    if (_context) {
        CGContextRestoreGState(_context);
    }
}

#pragma mark - 重写setter,getter方法
@synthesize strokeColor = _strokeColor;
- (void)setStrokeColor:(RGBColor *)strokeColor {

    if (_context) {
        
        _strokeColor = strokeColor;
        CGContextSetRGBStrokeColor(_context, strokeColor.red, strokeColor.green, strokeColor.blue, strokeColor.alpha);
    }
}
- (RGBColor *)strokeColor {

    return _strokeColor;
}

@synthesize fillColor = _fillColor;
- (void)setFillColor:(RGBColor *)fillColor {
    
    if (_context) {
        
        _fillColor = fillColor;
        CGContextSetRGBFillColor(_context, fillColor.red, fillColor.green, fillColor.blue, fillColor.alpha);
    }
}
- (RGBColor *)fillColor {
    
    return _fillColor;
}

@synthesize lineWidth = _lineWidth;
- (void)setLineWidth:(CGFloat)lineWidth {
    
    if (_context) {
        
        _lineWidth = lineWidth;
        CGContextSetLineWidth(_context, lineWidth);
    }
}
- (CGFloat)lineWidth {
    
    return _lineWidth;
}

@synthesize lineCap = _lineCap;
- (void)setLineCap:(CGLineCap)lineCap {
    
    if (_context) {
    
        _lineCap = lineCap;
        CGContextSetLineCap(_context, lineCap);
    }
    
}
- (CGLineCap)lineCap {

    return _lineCap;
}

@end

//
//  RGBColor.h
//  DrawRect
//
//  Created by YouXianMing on 15/7/2.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface RGBColor : NSObject

/**
 *  取值范围都在 0 - 1 之间
 */
@property (nonatomic) CGFloat  red;
@property (nonatomic) CGFloat  green;
@property (nonatomic) CGFloat  blue;
@property (nonatomic) CGFloat  alpha;

/**
 *  初始化颜色对象
 *
 *  @param red   红
 *  @param green 绿
 *  @param blue  蓝
 *  @param alpha 透明度
 *
 *  @return 颜色对象
 */
+ (instancetype)colorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha;

/**
 *  由UIColor初始化RGBColor
 *
 *  @param color
 *
 *  @return 实例对象
 */
+ (instancetype)colorWithUIColor:(UIColor *)color;

/**
 *  随机颜色
 *
 *  @return 实例对象
 */
+ (instancetype)randomColor;

@end

//
//  RGBColor.m
//  DrawRect
//
//  Created by YouXianMing on 15/7/2.
//  Copyright (c) 2015年 YouXianMing. All rights reserved.
//

#import "RGBColor.h"

@implementation RGBColor

+ (instancetype)colorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha {
    
    RGBColor *color = [[[self class] alloc] init];
    
    color.red   = red;
    color.green = green;
    color.blue  = blue;
    color.alpha = alpha;
    
    return color;
}

+ (instancetype)colorWithUIColor:(UIColor *)color {

    RGBColor *tmpColor = [[[self class] alloc] init];
    
    CGFloat red   = 0;
    CGFloat green = 0;
    CGFloat blue  = 0;
    CGFloat alpha = 0;
    
    [color getRed:&red green:&green blue:&blue alpha:&alpha];
    
    tmpColor.red   = red;
    tmpColor.green = green;
    tmpColor.blue  = blue;
    tmpColor.alpha = alpha;
    
    return tmpColor;
}

+ (instancetype)randomColor {

    RGBColor *color = [[[self class] alloc] init];
    
    color.red   = arc4random() % 256 / 255.f;
    color.green = arc4random() % 256 / 255.f;
    color.blue  = arc4random() % 256 / 255.f;
    color.alpha = arc4random() % 256 / 255.f;
    
    return color;
}

@end