iOS Quartz2D - 条纹背景

- (void)viewDidLoad
{
[super viewDidLoad];

//    self.view.backgroundColor = [UIColor redColor];

// 1.创建一行背景图片
CGFloat rowW = self.view.frame.size.width;
//    CGFloat rowH = 40;
CGFloat rowH = 30;
UIGraphicsBeginImageContextWithOptions(CGSizeMake(rowW, rowH), NO, 0.0);

CGContextRef ctx = UIGraphicsGetCurrentContext();
// 画矩形框
[[UIColor redColor] set];
CGContextAddRect(ctx, CGRectMake(0, 0, rowW, rowH));
CGContextFillPath(ctx);

// 2.画线
[[UIColor greenColor] set];
CGFloat lineWidth = 2;
CGContextSetLineWidth(ctx, lineWidth);
CGFloat dividerX = 0;
CGFloat dividerY = rowH - lineWidth;
CGContextMoveToPoint(ctx, dividerX, dividerY);
CGContextAddLineToPoint(ctx, rowW - dividerX, dividerY);
CGContextStrokePath(ctx);

// 3.取图
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

// 4.结束上下文
UIGraphicsEndImageContext();

// 5.设置为背景
self.textView.backgroundColor = [UIColor colorWithPatternImage:newImage];
}