画板例子思路
步骤一：自定义一个画板视图
步骤二：监听手指触摸事件，当手指在视图滑动的时候，就画线.
2.1在手指开始触摸的时候，创建可变路径，并且设置路径起始点。
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint point = [touch locationInView:self];
SUNBezierPath *path = [SUNBezierPath bezierPathWithWidth:_width andWithColor:_color andWithPoint:point];
_pathU = path;
[self.arrayM addObject:path];
}
2.2.
当手指移动的时候，给路径添加目标点，并且重新绘制视图。
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint point = [touch locationInView:self];
[_pathU addLineToPoint:point];
//
重绘
[self setNeedsDisplay];
}
2.3 当手指触摸结束，将路径保存起来，并释放当前路径
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
[_pathM addObject:_pathU];
CGPathRelease(_pathU.CGPath);
NSLog(@"%s",__func__);
}
注意：
1. [self setNeedsDisplay];这段代码不能少，否则在画板画不出东西。
2.当画板与slider绑定时，要通过awakeFromNib设置线宽，不然线宽默认为0.
- (void)awakeFromNib
{
_width =
2;
}
步骤三：实现绘制视图方法
3.1. 自定义路径类
+ (instancetype)bezierPathWithWidth:(CGFloat)width andWithColor:(UIColor *)color andWithPoint:(CGPoint)point
{
SUNBezierPath *path = [[SUNBezierPath alloc] init];
path.lineWidth = width;
path.color = color;
[path moveToPoint:point];
return path;
}
3.2.实现绘图方法
- (void)drawRect:(CGRect)rect
{
for (SUNBezierPath *path
in
self.arrayM) {
if ([path isKindOfClass:[UIImage class]]) {
UIImage *image = (UIImage *)path;
[image drawAtPoint:CGPointZero];
}else{
[path.color set];
[path stroke];
}
}
步骤四、在storyboard中定义工具栏
4.1 清屏
- (void)clearScreen
{
[self.arrayM
removeAllObjects];
[self
setNeedsDisplay];
}
直接把数组removeAllObjects
4.2 撤销
- (void)undo
{
[self.arrayM
removeLastObject];
[self
setNeedsDisplay];
}
4.3 保存
- (IBAction)save:(id)sender
{
//
截屏
//
开启上下文
UIGraphicsBeginImageContextWithOptions(_drawingView.bounds.size,
NO,
0.0);
//
获得当前上下文
CGContextRef ctr =
UIGraphicsGetCurrentContext();
//
把画板上的内容渲染都上下文
[_drawingView.layer
renderInContext:ctr];
UIImage *newImage =
UIGraphicsGetImageFromCurrentImageContext();
//
关闭上下文
UIGraphicsEndImageContext();
//
保存到相册里面
UIImageWriteToSavedPhotosAlbum(newImage,
self,
@selector(image:didFinishSavingWithError:contextInfo:),
nil);
}
调用MBProgressHUD 第三方框架
- (void)image:(UIImage
*)image didFinishSavingWithError:(NSError
*)error contextInfo:(void
*)contextInfo
{
if (error) {//
保存失败
[MBProgressHUD
showError:@"保存失败"];
}else{//
保存成功
[MBProgressHUD
showSuccess:@"保存成功"];
}
}
4.4 照片
- (IBAction)selectedPicture:(id)sender
{
//
去用户的操作
UIImagePickerController
*picker = [[UIImagePickerController
alloc]
init];
picker.sourceType
=
UIImagePickerControllerSourceTypeSavedPhotosAlbum;
[self
presentViewController:picker
animated:YES
completion:nil];
picker.delegate
=
self;
}
- (void)imagePickerController:(UIImagePickerController
*)picker didFinishPickingMediaWithInfo:(NSDictionary
*)info
{
NSLog(@"%@",info);
UIImage *newImage = info[UIImagePickerControllerOriginalImage];
SUNHandleView *handleV = [[SUNHandleView
alloc]
initWithFrame:self.drawingView.frame];
handleV.delegate
=
self;
handleV.image
= newImage;
[self.view
addSubview:handleV];
[self
dismissViewControllerAnimated:YES
completion:nil];
}
注意：去模拟器用户的相册要遵守UIImagePickerControllerDelegate协议，实现
- (void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
以modal的形式
[self presentViewController:picker animated:YES completion:nil];
关闭当初Modal出来的控制器
[self dismissViewControllerAnimated:YES completion:nil];
步骤五、实现从相处里面选择一张图片能够用手势操作。
添加手势
- (void)addGestureRecognizer
{
UIPanGestureRecognizer
*pan = [[UIPanGestureRecognizer
alloc]
initWithTarget:self
action:@selector(pan:)];
pan.delegate
=
self;
[_imageView
addGestureRecognizer:pan];
UIRotationGestureRecognizer
*rotation = [[UIRotationGestureRecognizer
alloc]
initWithTarget:self
action:@selector(rotation:)];
rotation.delegate
=
self;
[_imageView
addGestureRecognizer:rotation];
UIPinchGestureRecognizer
*pinch = [[UIPinchGestureRecognizer
alloc]
initWithTarget:self
action:@selector(pinch:)];
pinch.delegate
=
self;
[_imageView
addGestureRecognizer:pinch];
UILongPressGestureRecognizer
*longPress = [[UILongPressGestureRecognizer
alloc]
initWithTarget:self
action:@selector(longPress:)];
longPress.delegate
=
self;
[_imageView
addGestureRecognizer:longPress];
}
- (void)pan:(UIPanGestureRecognizer
*)pan
{
CGPoint point = [pan
translationInView:self];
_imageView.transform
=
CGAffineTransformTranslate(_imageView.transform,
point.x, point.y);
[pan
setTranslation:CGPointZero
inView:_imageView];
}
- (void)rotation:(UIRotationGestureRecognizer
*)rotation
{
_imageView.transform
=
CGAffineTransformRotate(_imageView.transform,
rotation.rotation);
rotation.rotation
=
0;
}
- (void)pinch:(UIPinchGestureRecognizer
*)pinch
{
_imageView.transform
=
CGAffineTransformScale(_imageView.transform,
pinch.scale, pinch.scale);
pinch.scale
=
1;
}
实现长按的操作
- (void)longPress:(UILongPressGestureRecognizer
*)longPress
{
if (longPress.state
==
UIGestureRecognizerStateEnded) {
[UIView
animateWithDuration:0.5
animations:^{
_imageView.alpha
=
0.3;
}
completion:^(BOOL
finished) {
[UIView
animateWithDuration:0.5
animations:^{
_imageView.alpha
=
1;
}
completion:^(BOOL
finished) {
//
截屏
UIGraphicsBeginImageContextWithOptions(self.bounds.size,
NO,
0.0);
CGContextRef ctr =
UIGraphicsGetCurrentContext();
[self.layer
renderInContext:ctr];
UIImage *image =
UIGraphicsGetImageFromCurrentImageContext();
NSData *data =
UIImagePNGRepresentation(image);
[data
writeToFile:@"/Users/sunjinshuai/Desktop/image.png"
atomically:YES];
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(image,
self,
@selector(image:didFinishSavingWithError:contextInfo:),
nil);
//
把图片传给控制器
if ([self.delegate
respondsToSelector:@selector(handleView:withImage:)])
{
[self.delegate
handleView:self
withImage:image];
}
//
从父控件中移除
[self
removeFromSuperview];
}];
}];
}
}
- (void)image:(UIImage
*)image didFinishSavingWithError:(NSError
*)error contextInfo:(void
*)contextInfo
{
if (error) {
[MBProgressHUD
showError:@"保存失败"];
}else{
[MBProgressHUD
showSuccess:@"保存成功"];
}
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer
*)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer
*)otherGestureRecognizer
{
return
YES;
}
- (void)setImage:(UIImage
*)image
{
_image = image;
_imageView.image
= image;
}
- (void)addImageView
{
UIImageView *imageV = [[UIImageView
alloc]
initWithFrame:self.bounds];
imageV.userInteractionEnabled
=
YES;
_imageView = imageV;
[self
addSubview:imageV];
}