IOS开发 图形绘制，绘制线条，矩形，和垂直和居中绘制文字

// 绘制直线
+ (void)toDrawLineFromX:(CGFloat)x1 Y:(CGFloat)y1 toX:(CGFloat)x2 toY:(CGFloat)y2 context:(CGContextRef)con{
    CGContextMoveToPoint(con, x1, y1);
    CGContextAddLineToPoint(con, x2, y2);
    CGContextSetLineWidth(con, 1);
    CGContextStrokePath(con);
}

//绘制矩形 ，fillColor填充色
+ (void)toDrawRect:(CGRect)rectangle color:fillColor context:(CGContextRef)ctx{
    
    //创建路径并获取句柄
    CGMutablePathRef
    path = CGPathCreateMutable();
    //将矩形添加到路径中
    CGPathAddRect(path,NULL,
                  rectangle);
    //获取上下文
    //将路径添加到上下文
    
    CGContextAddPath(ctx,
                     path);
    
    //设置矩形填充色
    [fillColor setFill];
    //矩形边框颜色
    [[UIColor
      whiteColor] setStroke];
    //边框宽度
    CGContextSetLineWidth(ctx,0);
    //绘制
    CGContextDrawPath(ctx,
                      kCGPathFillStroke);
    CGPathRelease(path);
}

///绘制文字，rect1指定矩形，绘制文字在这个矩形水平和垂直居中
+ (void)toDrawTextWithRect:(CGRect)rect1 str:(NSString*)str1 context:(CGContextRef)context{
    if( str1 == nil || context == nil)
        return;
    
    CGContextSetLineWidth(context, 1.0);
    CGContextSetRGBFillColor (context, 0.01, 0.01, 0.01, 1);
    
    //段落格式
    NSMutableParagraphStyle *textStyle = [[NSMutableParagraphStyle defaultParagraphStyle] mutableCopy];
    textStyle.lineBreakMode = NSLineBreakByWordWrapping;
    textStyle.alignment = NSTextAlignmentCenter;//水平居中
    //字体
    UIFont  *font = [UIFont boldSystemFontOfSize:22.0];
    //构建属性集合
    NSDictionary *attributes = @{NSFontAttributeName:font, NSParagraphStyleAttributeName:textStyle};
    //获得size
    CGSize strSize = [str1 sizeWithAttributes:attributes];
    CGFloat marginTop = (rect1.size.height - strSize.height)/2;
    //垂直居中要自己计算
    CGRect r = CGRectMake(rect1.origin.x, rect1.origin.y + marginTop,rect1.size.width, strSize.height);
    [str1 drawInRect:r withAttributes:attributes];
}

　　定义： #define drawLine(x1,y1,x2,y2,con) [DrawUtil toDrawLineFromX:x1 Y:y1 toX:x2 toY:y2 context:con]

 　　//获得上下文
　　CGContextRef con = UIGraphicsGetCurrentContext();
     CGContextClearRect(con, rect);

　　//画线，
　　drawLine(x,y,x+rectWidth,y,con);

　　//矩形
    [DrawUtil toDrawRect:CGRectMake(x*unitWidth+1, y*unitHeight+1,unitWidth-1, unitHeight-1) color:[UIColor whiteColor] context:con];

    //文字
　　[DrawUtil toDrawTextWithRect:rect1 str:@"你" context:context];