macOS开发之画板

最近在研究mac客户端上做一个画板功能，首先还是按照iOS开发的经验开始在cocoa框架中需要相关的或者类似的类，下面简单说说走过的弯路吧

1. 首先肯定是要去查- (void)drawRect:(NSRect)dirtyRect方法相关的类或者工具类，结果肯定是否定的，因为画板肯定是需要实时绘制，我也了解过display方法可以更新绘制，但是没有往下深究
2. 然后就是CAShapeLayer和NSBezierPath组合，做过iOS的小伙伴们都很熟悉，可是cocoa框架中我没有找到把NSBezierPath对象赋值给CAShapeLayer的属性path的方法，NSBezierPath类没有CGPath属性(UIBezierPath有这个属性)，绝望了
3. 最后使用CAShapeLayer和CGMutablePathRef组合，细节请看下文代码

解决：CAShapeLayer和CGMutablePathRef组合

1. 创建一个集成自NSView的类
2. .h文件没有内容就不贴了，直接上.m文件

#import "SHSettingTestView.h"
#import <QuartzCore/QuartzCore.h>

@interface SHSettingTestView ()
@property (nonatomic , strong) CAShapeLayer         *shapeLayer;
@property (nonatomic)          CGMutablePathRef     path;
@end

@implementation SHSettingTestView

- (instancetype)initWithFrame:(NSRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        self.wantsLayer = YES;
        self.layer.backgroundColor = NSColor.whiteColor.CGColor;
    }
    return self;
}
- (BOOL)mouseDownCanMoveWindow
{
    [super mouseDownCanMoveWindow];
    return NO;
}
- (void)updateTrackingAreas
{
    NSTrackingArea *trackingArea = [[NSTrackingArea alloc] initWithRect:self.bounds options:(NSTrackingEnabledDuringMouseDrag|NSTrackingActiveInActiveApp|NSTrackingInVisibleRect|NSTrackingAssumeInside|NSTrackingCursorUpdate)owner:self userInfo:nil];
    [self addTrackingArea:trackingArea];
}
- (void)mouseDown:(NSEvent *)event
{
    CGPathMoveToPoint(self.path, nil, event.locationInWindow.x, event.locationInWindow.y);
    self.shapeLayer.path = self.path;
}
- (void)mouseDragged:(NSEvent *)event
{
    CGPathAddLineToPoint(self.path, nil, event.locationInWindow.x, event.locationInWindow.y);
    self.shapeLayer.path = self.path;
}

#pragma mark - lazy
- (CAShapeLayer *)shapeLayer
{
    if (!_shapeLayer) {
        _shapeLayer = [CAShapeLayer layer];
        _shapeLayer.frame = self.bounds;
        _shapeLayer.fillColor = [NSColor clearColor].CGColor;
        _shapeLayer.lineWidth = 1.0;
        _shapeLayer.lineCap = kCALineCapRound;
        _shapeLayer.lineJoin = kCALineJoinRound;
        _shapeLayer.strokeColor = NSColor.blueColor.CGColor;
        [self.layer addSublayer:_shapeLayer];
    }
    return _shapeLayer;
}
- (CGMutablePathRef)path
{
    if (!_path) {
        _path = CGPathCreateMutable();
    }
    return _path;
}
@end

• updateTrackingAreas方法之前写过文章传送门
• mouseDownCanMoveWindow该方法防治穿透导致点击事件冲突

完成