iOS 两张图片合并成一张。

（一）

UIImage * icon = self.groupIconView.image;//[UIImage imageNamed:@""];

//以1.png的图大小为底图

//CGImageRef imgRef = icon.CGImage;

// CGFloat w = CGImageGetWidth(imgRef);

//CGFloat h = CGImageGetHeight(imgRef);

UIImage *img1 = [UIImage imageNamed:@"bg_"];

// CGImageRef imgRef1 = img1.CGImage;

//CGFloat w1 = CGImageGetWidth(imgRef1);

//CGFloat h1 = CGImageGetHeight(imgRef1);

//以1.png的图大小为画布创建上下文

UIGraphicsBeginImageContext(CGSizeMake(100, 100));

[img1 drawInRect:CGRectMake(0, 0, 100, 100)];//先把1.png 画到上下文中

[icon drawInRect:CGRectMake(4, 4, 92, 92)];//再把小图放在上下文中

UIImage *resultImg = UIGraphicsGetImageFromCurrentImageContext();//从当前上下文中获得最终图片

UIGraphicsEndImageContext();//关闭上下文

// CGImageRelease(imgRef);

// CGImageRelease(imgRef1);

icon = resultImg;

应用场景二维码中间的图标加边框等等：

// 生成带图片的二维码

[UIImage qrImageWithString:content size:myWidth * qrScale iconImage:icon scale: margin/(myWidth * qrScale) completion:^(UIImage *image) {

weakSelf.qrImageView.image = image;

}

#pragma mark - 带图片二维码（图片指定比例、方形）

+ (void)qrImageWithString:(NSString *)string size:(CGFloat)size iconImage:(UIImage *)iconImage scale:(CGFloat)scale completion:(void (^)(UIImage * image))completion {

// 传入 CenterImgType_Square scale

[UIImage qrImageWithString:string size:size CenterImageType:CenterImgType_CornorRadious iconImage:iconImage scale:scale completion:completion];//CenterImgType_Square 方形 CenterImgType_CornorRadious 切圆角

}

（二）

如果内置小图片要求为圆角，则需要绘图

//绘图圆角

CGRect rect = (CGRect){0.f, 0.f, icon.size};

UIGraphicsBeginImageContextWithOptions(icon.size, NO, UIScreen.mainScreen.scale);

CGContextAddPath(UIGraphicsGetCurrentContext(),

[UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:8].CGPath);

CGContextClip(UIGraphicsGetCurrentContext());

[icon drawInRect:rect];

UIImage *output = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

扩展贝塞尔曲线学习：

关于绘制这块，系统已经提供了几个内置的方法：

+ (instancetype)bezierPathWithRect:(CGRect)rect;
+ (instancetype)bezierPathWithOvalInRect:(CGRect)rect;
+ (instancetype)bezierPathWithRoundedRect:(CGRect)rect cornerRadius:(CGFloat)cornerRadius; // rounds all corners with the same horizontal and vertical radius
+ (instancetype)bezierPathWithRoundedRect:(CGRect)rect byRoundingCorners:(UIRectCorner)corners cornerRadii:(CGSize)cornerRadii;
+ (instancetype)bezierPathWithArcCenter:(CGPoint)center radius:(CGFloat)radius startAngle:(CGFloat)startAngle endAngle:(CGFloat)endAngle clockwise:(BOOL)clockwise;
+ (instancetype)bezierPathWithCGPath:(CGPathRef)CGPath;

今天就简单的介绍一下这几个方法

1:画矩形

(instancetype)bezierPathWithRect:(CGRect)rect;
系统方法，画矩形
rect: 矩形的Frame

- (void)drawRect:(CGRect)rect
{// 设置线的填充色[[UIColor redColor] setStroke];// 新建一个bezier对象，此对象用于绘制矩形，需要传入绘制的矩形的FrameUIBezierPath *bezierPath = [UIBezierPath bezierPathWithRect:CGRectMake(10, 10, 280, 280)];// 设置线宽度bezierPath.lineWidth = 10;// 设置线两头样式bezierPath.lineCapStyle = kCGLineCapRound;// 开始绘制[bezierPath stroke];
}

屏幕快照 2015-12-30 14.49.09.png

2:画矩形，圆角矩形

(instancetype)bezierPathWithRoundedRect:(CGRect)rect cornerRadius:(CGFloat)cornerRadius; // rounds all corners with the same horizontal and vertical radius
系统方法，绘制一个圆角的矩形
rect: 矩形的Frame
cornerRadius: 圆角的半径

- (void)drawRect:(CGRect)rect
{// 设置线的填充色[[UIColor redColor] setStroke];// 新建一个bezier对象，此对象用于绘制一个圆角矩形UIBezierPath *bezierPath = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(10, 10, 280, 280)cornerRadius:30];// 设置线宽度bezierPath.lineWidth = 10;// 开始绘制[bezierPath stroke];
}

屏幕快照 2015-12-30 15.08.32.png

3:画矩形，部分圆角的矩形

(instancetype)bezierPathWithRoundedRect:(CGRect)rect byRoundingCorners:(UIRectCorner)corners cornerRadii:(CGSize)cornerRadii;
画一个部分圆角的矩形
rect: 需要画的矩形的Frame
corners: 哪些部位需要画成圆角
cornerRadii: 圆角的Size

- (void)drawRect:(CGRect)rect
{// 设置线的填充色[[UIColor redColor] setStroke];// 新建一个bezier对象，此对象用于绘制一个部分圆角的矩形，左上、右下UIBezierPath *bezierPath = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(10, 10, 280, 280)byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomRightcornerRadii:CGSizeMake(10, 10)];// 设置线宽度bezierPath.lineWidth = 10;// 开始绘制[bezierPath stroke];
}

屏幕快照 2015-12-30 15.35.48.png

4:画圆，内切圆

(instancetype)bezierPathWithOvalInRect:(CGRect)rect;
画圆，这个方法绘制的是一个矩形的内切圆
rect: 矩形的Frame

- (void)drawRect:(CGRect)rect
{// 设置线的填充色[[UIColor redColor] setStroke];// 新建一个bezier对象，此对象用于绘制内切圆，需要传入绘制内切圆的矩形的FrameUIBezierPath *bezierPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(10, 10, 280, 280)];// 设置线宽度bezierPath.lineWidth = 10;// 设置线两头样式bezierPath.lineCapStyle = kCGLineCapRound;// 开始绘制[bezierPath stroke];
}

屏幕快照 2015-12-30 14.57.05.png

5:画圆弧

(instancetype)bezierPathWithArcCenter:(CGPoint)center radius:(CGFloat)radius startAngle:(CGFloat)startAngle endAngle:(CGFloat)endAngle clockwise:(BOOL)clockwise;
center: 圆心坐标
radius: 圆的半径
startAngle: 绘制起始点角度
endAngle: 绘制终点角度
clockwise: 是否顺时针

- (void)drawRect:(CGRect)rect
{// 设置线的填充色[[UIColor redColor] setStroke];// 新建一个bezier对象，此对象用于绘制一个圆弧UIBezierPath *bezierPath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150)radius:110startAngle:0endAngle:M_PI_2clockwise:NO];// 设置线宽度bezierPath.lineWidth = 10;// 开始绘制[bezierPath stroke];
}

屏幕快照 2015-12-30 16.32.44.png