iOS塗鴉-自由畫筆可以用到的代碼

1.線段模用來存儲線段資訊

//
//  Line.h

//  線段模型

#import <UIKit/UIKit.h>


@interface Line : NSObject
/**
 *  線條所包含的所有點
 */
@property (nonatomic,strong)NSMutableArray <__kindof NSValue *>*linePoints;
/**
 *  線條的顔色
 */
@property (nonatomic,strong)UIColor *lineColor;
/**
 *  線條的粗細
 */
@property (nonatomic,assign)NSInteger lineWidth;
@end
           

#import "Line.h"

@implementation Line

- (instancetype)init
{
    if (self=[super init]) {
        self.linePoints = [NSMutableArray array];
    }
    
    return self;
}

@end
           

2.自定義控件

//
//  DrawLine.h
//  建立一個直線

#import <UIKit/UIKit.h>

@interface DrawLine : UIView

/**
 *  線的顔色(用于接收外部傳進來的顔色)
 */
@property (nonatomic, strong) UIColor *lineColor;
/**
 *  線寬(用于接收外部傳進來)
 */
@property (nonatomic, assign) NSInteger lineWidth;

@end
           

//
//  DrawLine.m


#import "DrawLine.h"
#import "Line.h"

@interface DrawLine()
/**
 *  存放所有線條的資訊(顔色、坐标、寬度)
 */
@property(nonatomic,strong)NSMutableArray *allLineInfos;
@end

@implementation DrawLine

- (NSMutableArray *)lineInfos
{
    if (_allLineInfos == nil) {
        _allLineInfos = [NSMutableArray array];
    }
    return _allLineInfos;
}

/**
 *  從代碼建立控件會調用(這個方法裡做一次性初始化設定)
 */
- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        self.backgroundColor = [UIColor clearColor];
        self.lineWidth = 2;
        self.lineColor = [UIColor redColor];
    }
    return self;
}

#pragma mark - touche
/**
 *  開始觸摸
 */
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    // 1.取出UITouch對象
    UITouch *touch=[touches anyObject];
    
    // 2.建立一個線條資訊模型
    Line *info = [Line new];
    info.lineColor = self.lineColor;
    info.lineWidth = self.lineWidth;
    [info.linePoints addObject:[NSValue valueWithCGPoint:[touch locationInView:self]]];
    
    // 3.把該線條資訊模型添加到數組
    [self.allLineInfos addObject:info];
    
    // 4.重繪
    [self setNeedsDisplay];
}

/**
 *  觸摸點一直在移動就會調用
 */
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    // 1.取出所有point
    NSArray* MovePointArray=[touches allObjects];
    
    // 2.取出最新添加的一個線段資訊模型
    Line *lastInfo = [self.lineInfos lastObject];
    
    // 3.給這個模型的linePoints屬性添加值
    [lastInfo.linePoints addObject:[NSValue valueWithCGPoint:[[MovePointArray objectAtIndex:0] locationInView:self]]];
    
    // 4.重繪
    [self setNeedsDisplay];
}

#pragma mark - 繪制
/**
 *  根據現有的線條繪制相應的圖形
 */
- (void)drawRect:(CGRect)rect
{
    CGContextRef context=UIGraphicsGetCurrentContext();
    CGContextSetLineCap(context, kCGLineCapRound);
    CGContextSetLineJoin(context, kCGLineJoinRound);
    
    if (self.allLineInfos.count>0) {
        for (int i=0; i<[self.allLineInfos count]; i++) {
            Line *info = self.allLineInfos[i];
            
            CGContextBeginPath(context);
            CGPoint myStartPoint=[[info.linePoints objectAtIndex:0] CGPointValue];
            CGContextMoveToPoint(context, myStartPoint.x, myStartPoint.y);
            
            if (info.linePoints.count>1) {
                for (int j=0; j<[info.linePoints count]-1; j++) {
                    CGPoint myEndPoint=[[info.linePoints objectAtIndex:j+1] CGPointValue];
                    CGContextAddLineToPoint(context, myEndPoint.x,myEndPoint.y);
                }
            }else {
                CGContextAddLineToPoint(context, myStartPoint.x,myStartPoint.y);
            }
//            CGContextSetStrokeColorWithColor(context, info.lineColor.CGColor);
            CGContextSetLineWidth(context, info.lineWidth);
            
            // 定義陰影
            NSShadow* shadow4 = [[NSShadow alloc] init];
            [shadow4 setShadowColor: info.lineColor];
            [shadow4 setShadowOffset: CGSizeMake(0.0, 0.0)];
            [shadow4 setShadowBlurRadius: info.lineWidth * 1.2];
            
            // 繪制陰影
            CGContextSaveGState(context);
            CGContextSetShadowWithColor(context, shadow4.shadowOffset, shadow4.shadowBlurRadius, [shadow4.shadowColor CGColor]);
            [[UIColor colorWithRed:245/255.0 green:255/255.0 blue:243/255.0 alpha:1.0] setStroke];
            
            CGContextStrokePath(context);
        }
    }

}

@end
           

3.控制器裡如何使用？

DrawLine *line = [[DrawLine alloc]initWithFrame:CGRectMake(0, 0, screenW, screenH)];
    line.lineWidth = self.currentWidth;
    line.lineColor = self.currentColor;
    [self.bgView addSubview:line];