简介
由于项目需求，安卓的同事做了这样一个功能，iOS不用做，我还是找了找资料，做了一个小dome，GitHub地址，进入正题。
1.封装一个view作为签名视图，属性很好懂，就是设置签名的线的颜色，线宽，还有最后生成的图片，以及图片的缩放比例，方法分别是准备开始画线，重置以及保存
#import <UIKit/UIKit.h>
@interface CJSignatureView : UIView
// 线宽 默认1
@property (nonatomic, assign) CGFloat lineWidth;
// 线颜色 默认黑
@property (nonatomic, strong) UIColor *lineColor;
// 生成图片的缩放比例 默认1不缩放 范围0.1~1.0
@property (nonatomic, assign) CGFloat imageScale;
// 生成的图片
@property (nonatomic, strong) UIImage *signImage;
// 初始化视图之后调用 准备画图
- (void)startDraw;
// 重置
- (void)resetDraw;
// 保存成图片
- (void)saveDraw;
@end
2.初始化path
// 先声明两个全局变量
UIBezierPath *path;// 签名的线
CGPoint previousPoint;// 上一个点
#pragma mark 准备开始签名
- (void)startDraw
{
// 背景色
self.backgroundColor = [UIColor whiteColor];
// 初始化 设置属性
path = [UIBezierPath bezierPath];
// 线宽
path.lineWidth = _lineWidth ? _lineWidth : 1;
// 线颜色
if (_lineColor) {
[_lineColor set];
}
}
3.画线，将第一个点击的点和之后移动到的点连接
#pragma mark 画线刚开始，保存上一个点
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
// 获取点击点坐标
UITouch * touch = touches.anyObject;
CGPoint currentPoint = [touch locationInView:self];
// 保存成上一点
previousPoint = currentPoint;
// 开始点移动到点击点
[path moveToPoint:currentPoint];
}
#pragma mark 开始画线，连接上一个点和当前点
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
// 获取点击点坐标
UITouch * touch = touches.anyObject;
CGPoint currentPoint = [touch locationInView:self];
// 获取两点中点
CGPoint midPoint = midpoint(previousPoint, currentPoint);
// 画曲线
[path addQuadCurveToPoint:midPoint controlPoint:previousPoint];
// 替换当前点为上一点
previousPoint = currentPoint;
// 画图，调用系统的darwRect:
[self setNeedsDisplay];
}
#pragma mark 系统画线方法
- (void)drawRect:(CGRect)rect
{
[path stroke];
}
4.写重置方法，调用startDraw重置属性，调用setNeedsDisplay重画图（path这时候时空的）
#pragma mark 重置path
- (void)resetDraw
{
[self startDraw];
[self setNeedsDisplay];
}
5.写保存方法，这里涉及到2个方法，截图以及缩放
#pragma mark 保存成图片
- (void)saveDraw
{
self.signImage = [self captureWithView:self];
if (!_imageScale) {
return;
}
// 这里控制范围，范围可以自己定
if (_imageScale < 0.1) {
_imageScale = 0.1;
}
if (_imageScale > 1) {
_imageScale = 1;
}
if (_imageScale != 1) {
[self scaleImage];
}
}
#pragma mark 缩放图片
- (UIImage *)scaleImage
{
// 用这个方法 画质会变渣
// UIGraphicsBeginImageContext(CGSizeMake(_signImage.size.width * _imageScale, _signImage.size.height * _imageScale));
// [_signImage drawInRect:CGRectMake(0, 0, _signImage.size.width * _imageScale, _signImage.size.height * _imageScale)];
// self.signImage = UIGraphicsGetImageFromCurrentImageContext();
// UIGraphicsEndImageContext();
// 判断机型
if([[UIScreen mainScreen] scale] == 2.0){ // @2x
UIGraphicsBeginImageContextWithOptions(CGSizeMake(_signImage.size.width * _imageScale, _signImage.size.height * _imageScale), NO, 2.0);
}else if([[UIScreen mainScreen] scale] == 3.0){ // @3x ( iPhone 6plus 、iPhone 6s plus)
UIGraphicsBeginImageContextWithOptions(CGSizeMake(_signImage.size.width * _imageScale, _signImage.size.height * _imageScale), NO, 3.0);
}else{
UIGraphicsBeginImageContext(CGSizeMake(_signImage.size.width * _imageScale, _signImage.size.height * _imageScale));
}
// 绘制改变大小的图片
[_signImage drawInRect:CGRectMake(0, 0, _signImage.size.width * _imageScale, _signImage.size.height * _imageScale)];
// 从当前context中创建一个改变大小后的图片
_signImage = UIGraphicsGetImageFromCurrentImageContext();
// 使当前的context出堆栈
UIGraphicsEndImageContext();
// 返回新的改变大小后的图片
return self.signImage;
}
#pragma mark 截屏
- (UIImage *)captureWithView:(UIView *)view
{
CGRect screenRect = [view bounds];
UIGraphicsBeginImageContext(screenRect.size);
CGContextRef ctx = UIGraphicsGetCurrentContext();
[view.layer renderInContext:ctx];
UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
6.调用，调用比较简单了直接上代码了，这里写的例子是A控制器跳转到B控制器，在B中签名，并把图片返回到A显示
// A控制器.m代码
@implementation ViewController
{
UIImageView *showImageView;
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor cyanColor];
showImageView = [[UIImageView alloc] initWithFrame:self.view.frame];
[self.view addSubview:showImageView];
showImageView.contentMode = UIViewContentModeScaleAspectFit;
}
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
CJDrawViewController *VC = [CJDrawViewController new];
VC.delegate = self;
[self presentViewController:VC animated:YES completion:nil];
}
// 代理方法
- (void)returnImage:(UIImage *)signImage
{
showImageView.frame = CGRectMake(0, 0, signImage.size.width, signImage.size.height);
showImageView.center = self.view.center;
showImageView.image = signImage;
}
// B控制器.h代码
@protocol CJDrawViewControllerDelegate <NSObject>
// 返回签名图片
- (void)returnImage:(UIImage *)signImage;
@end
@interface CJDrawViewController : UIViewController
@property (nonatomic, assign) id<CJDrawViewControllerDelegate> delegate;
@end
B控制器.m代码
#import "CJDrawViewController.h"
#import "CJSignatureView.h"
@interface CJDrawViewController ()
@property (nonatomic, strong) CJSignatureView *signView;
@end
@implementation CJDrawViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor yellowColor];
[self.view addSubview:self.signView];
[self createView];
}
#pragma mark 初始化
- (CJSignatureView *)signView
{
if (!_signView) {
_signView = [[CJSignatureView alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height/2.0-200/2.0, self.view.frame.size.width, 200)];
_signView.lineColor = [UIColor redColor];
_signView.lineWidth = 2;
_signView.imageScale = 0.5;
[_signView startDraw];
}
return _signView;
}
#pragma mark 创建按钮
- (void)createView
{
NSArray *titleArr = @[@"返回", @"重置", @"保存"];
CGFloat btnW = self.view.frame.size.width/3.0;
for (int i = 0; i < titleArr.count; i++) {
UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];
btn.frame = CGRectMake(btnW*i, self.view.frame.size.height-40, btnW, 40);
[self.view addSubview:btn];
[btn setTitle:titleArr[i] forState:UIControlStateNormal];
[btn addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];
btn.tag = 100+i;
}
}
#pragma mark 按钮点击方法
- (void)btnAction:(UIButton *)btn
{
switch (btn.tag) {
case 100:
[self dismissViewControllerAnimated:YES completion:nil];
break;
case 101:
[_signView resetDraw];
break;
case 102:
[_signView saveDraw];
if ([self.delegate respondsToSelector:@selector(returnImage:)]) {
[self.delegate returnImage:_signView.signImage];
}
[self dismissViewControllerAnimated:YES completion:nil];
break;
default:
break;
}
}
这样，一个简单的签名就封装好了，里面有许多的东西是可以根据具体需求修改的。
结语：限于水平，本文只写了一些基本用法和注意事项，如果文中存在错误请指出，我会及时修改。
