- (void)pan:(UIPanGestureRecognizer *)pan {
//获取开始的触摸点
CGPoint startP = [pan locationInView:self];
if (pan.state == UIGestureRecognizerStateBegan) {
//创建贝塞尔路径
_path = [[DrawPath alloc]init];
_path.lineWidth = _lineWidth;
_path.pathColor = _pathColor;
//不能在手指抬起时将路径添加到数组，因为在遍历数组画线时路径还没有被添加到数组里面
[_pathArr addObject:_path];
//设置起点
[_path moveToPoint:startP];
}
//连线
[_path addLineToPoint:startP];
//重绘，调用drawRect方法
[self setNeedsDisplay];
}
画线实现drawRect方法，绘制线条或者图片时，是把数组中的路径全部画出来
- (void)drawRect:(CGRect)rect {
//把所有路径画出来
for (DrawPath *path in self.pathArr) {
if ([path isKindOfClass:[UIImage class]]) {
//画图
UIImage *image = (UIImage *)path;
[image drawInRect:rect];
}else {
//画线
[path.pathColor set];
[path stroke];
}
}
}
当把图片添加到画板时
- (void)setImage:(UIImage *)image {
_image = image;
[self.pathArr addObject:image];
//重绘调用drawRect才能在画板上显示图片
[self setNeedsDisplay];
}
还可以把直接更新路径数组的操作封装在画板中
- (void)clear {
//清除
[self.pathArr removeAllObjects];
[self setNeedsDisplay];
}
- (void)undo {
//撤销
[self.pathArr removeLastObject];
[self setNeedsDisplay];
}
控制器中：
@interface ViewController () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>
@property (weak, nonatomic) IBOutlet DrawView *drawView;
@end
实现几个按钮对画板的操作：
- (IBAction)clear:(id)sender {
//清屏
[_drawView clear];
}
- (IBAction)undo:(id)sender {
//撤销
[_drawView undo];
}
- (IBAction)eraser:(id)sender {
//擦除 就是把路径的颜色设置为画板的背景色，假象
_drawView.pathColor = _drawView.backgroundColor;
_drawView.lineWidth = 20;
}
- (IBAction)changeLineWidth:(UISlider *)sender {
//改变路径线宽
_drawView.lineWidth = sender.value;
}
- (IBAction)changeColor:(UIButton *)sender {
//改变路径颜色
_drawView.pathColor = sender.backgroundColor;
}
- (IBAction)pickPhoto:(id)sender {
//选择照片
//弹出系统相册
UIImagePickerController *picker = [[UIImagePickerController alloc]init];
//设置选择控制器的来源 UIImagePickerControllerSourceTypeSavedPhotosAlbum:照片库
picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
//设置代理
picker.delegate = self;
//modal出控制器
[self presentViewController:picker animated:YES completion:nil];
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {
//获取选择的图片
UIImage *image = info[UIImagePickerControllerOriginalImage];
//创建一个处理图片的view
ImageHandleView *handleView = [[ImageHandleView alloc]initWithFrame:self.drawView.bounds];
handleView.handleCompletionBlock = ^(UIImage *image){
_drawView.image = image;
};
[self.drawView addSubview:handleView];
//将图片画在画板上
handleView.image = image;
//_drawView.image = image;
//dismiss
[self dismissViewControllerAnimated:YES completion:nil];
//NSLog(@"%@", info);
}
- (IBAction)save:(id)sender {
[UIView animateWithDuration:0.15 animations:^{
//保存当前画板上的内容
//开启上下文
UIGraphicsBeginImageContextWithOptions(_drawView.bounds.size, NO, 0);
//获取位图上下文
CGContextRef ctx = UIGraphicsGetCurrentContext();
//把控件上的图层渲染到上下文
[_drawView.layer renderInContext:ctx];
//获取上下文中的图片
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
//关闭上下文
UIGraphicsEndImageContext();
//保存图片到相册
UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
self.drawView.alpha = 0;
} completion:^(BOOL finished) {
[UIView animateWithDuration:0.15 animations:^{
self.drawView.alpha = 1;
}];
}];
}
//保存成功后的方法必须是这个，不能随便写
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
NSLog(@"保存成功");
}
