我是堆栈溢出的新成员，但我一直在使用这些论坛中找到的答案多年。我有一个问题可以通过对我的主题进行更彻底的研究来更好地回答，但是我正在为我在学校的一个班级进行合作，并且已经被委托对其他人的代码进行一些更改......并且坦率地说我准时不足，所以我希望能在这里得到一些帮助。
我已经研究过这里发现的其他一些问题和答案，但它们似乎都没有直接解决我的问题。
我有一个应该捕获人签名的应用程序。它目前适用于iphone 4，当我尝试更换硬件时会出现问题。如果我选择一个3.5英寸的屏幕，或任何版本的ipad，我用我的签名制作的触摸在屏幕顶部是准确的，但随着我向下移动逐渐变得越来越不准确（就好像图像被描绘一样）是一个4英寸的屏幕，而触摸是在3.5英寸的屏幕上发生的）
这是我的ViewController代码：
@implementation SignatureViewController
@synthesize clearButton;
@synthesize tempDrawImage;
@synthesize tempSaveImage;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
red = 0.0/255.0;
green = 0.0/255.0;
blue = 0.0/255.0;
brush = 5.0;
opacity = 1.0;
[self.tempDrawImage setImage:[UIImage imageNamed:@"bg-signature-portrait.png"]];
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
mouseSwiped = NO;
UITouch *touch = [touches anyObject];
lastPoint = [touch locationInView:self.view];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
mouseSwiped = YES;
UITouch *touch = [touches anyObject];
CGPoint currentPoint = [touch locationInView:self.view];
UIGraphicsBeginImageContext(self.view.frame.size);
[self.tempDrawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), brush );
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), red, green, blue, 1.0);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(),kCGBlendModeNormal);
CGContextStrokePath(UIGraphicsGetCurrentContext());
self.tempDrawImage.image = UIGraphicsGetImageFromCurrentImageContext();
[self.tempDrawImage setAlpha:opacity];
UIGraphicsEndImageContext();
lastPoint = currentPoint;
HousingAppDelegate *appDelegate = [[UIApplication sharedApplication]delegate];
appDelegate.tempSig = self.tempDrawImage.image;
}
- (IBAction)clearSig:(id)sender {
[self.tempDrawImage setImage:[UIImage imageNamed:@"bg-signature-portrait.png"]];
return;
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
if(!mouseSwiped) {
UIGraphicsBeginImageContext(self.view.frame.size);
[self.tempDrawImage.image drawInRect:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), brush);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), red, green, blue, opacity);
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
CGContextFlush(UIGraphicsGetCurrentContext());
self.tempDrawImage.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
}
}
- (void)viewDidDisappear:(BOOL)animated {
[self.tempDrawImage setImage:[UIImage imageNamed:@"bg-signature-portrait.png"]];
}
@end
我认为touchesMoved方法中的“self.view.frame.size.width”和“self.view.frame.size.height”会提取有关硬件屏幕大小的信息并动态填充但显然事实并非如此。
非常感谢任何帮助。
此外，目前正在将签名保存在bg-signature-portriat.png背景图像（一个带有x的简单线条）的顶部。我想单独获得签名，但无法理解如何做到这一点（也许这需要分层UIImage？还有一些不能轻易解释而无法访问故事板？）。
非常感谢你，我保证会有更好的问题（希望有几个答案）继续前进。
答案 0 :(得分：1)
试试这可能对您有所帮助，并且很容易更改代码
- (void)showPopOverscreenforSignatureScreen //:(UIButton *)sender call this method in button action
{
mouseMoved = 0;
[SignatureContentView setHidden:NO];
SignatureContentView.frame=CGRectMake(kLabelWidth+20, 150, 500, 200);
signaturedImageView =(UIImageView *)[self.view viewWithTag:imageViewSelectedTagvalue];
[signaturedImageView setHidden:YES];
}
- (void)allocPopOverscreenforSignatureScreen
{
SignatureContentView =[[UIView alloc]initWithFrame:CGRectMake(0, 50, 500, 200)];
SignatureContentView.layer.cornerRadius=5.0f;
SignatureContentView.layer.backgroundColor=[UIColor lightGrayColor].CGColor;
SignatureContentView.backgroundColor=[UIColor grayColor];
[self.view addSubview:SignatureContentView];
signatureImageView = [[UIImageView alloc] initWithImage:nil];
signatureImageView.layer.cornerRadius=5.0f;
signatureImageView.layer.backgroundColor=[UIColor lightGrayColor].CGColor;
signatureImageView.backgroundColor=[UIColor colorWithPatternImage:[UIImage imageNamed:@"textured_paper_.png"]];
signatureImageView.frame = CGRectMake(0, 0, 500, 148);
signatureImageView.userInteractionEnabled=YES;
[SignatureContentView addSubview:signatureImageView];
mouseMoved = 0;
UIButton *cancelButton =[UIButton buttonWithType:UIButtonTypeCustom];
cancelButton.frame=CGRectMake(50, 150, 100, 40);
[cancelButton setTitle:@"Cancel" forState:UIControlStateNormal];
cancelButton.backgroundColor=[UIColor colorWithRed:0.2 green:0.6 blue:.9 alpha:1.5];
[cancelButton setTitleColor:[UIColor yellowColor] forState:UIControlStateNormal];
[cancelButton addTarget:self action:@selector(cancelsignatureImageView) forControlEvents:UIControlEventTouchUpInside];
[SignatureContentView addSubview:cancelButton];
UIButton *clearButton =[UIButton buttonWithType:UIButtonTypeCustom];
clearButton.frame=CGRectMake(200, 150, 100, 40);
[clearButton setTitle:@"Clear" forState:UIControlStateNormal];
clearButton.backgroundColor=[UIColor colorWithRed:0.2 green:0.6 blue:.9 alpha:1.5];
[clearButton setTitleColor:[UIColor yellowColor] forState:UIControlStateNormal];
[clearButton addTarget:self action:@selector(clearsignatureImageView) forControlEvents:UIControlEventTouchUpInside];
[SignatureContentView addSubview:clearButton];
UIButton *useButton =[UIButton buttonWithType:UIButtonTypeCustom];
useButton.frame=CGRectMake(350, 150, 100, 40);
useButton.backgroundColor=[UIColor colorWithRed:0.2 green:0.6 blue:.9 alpha:1.5];
[useButton setTitle:@"Use" forState:UIControlStateNormal];
[useButton setTitleColor:[UIColor yellowColor] forState:UIControlStateNormal];
[useButton addTarget:self action:@selector(getSignaturefromsignatureImageView) forControlEvents:UIControlEventTouchUpInside];
[SignatureContentView addSubview:useButton];
[SignatureContentView setHidden:YES];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
mouseSwiped = NO;
//The below statements will help to get the exact point user touches with out this it will take ZERO yaxis
UITouch *touch = [touches anyObject];
lastPoint = [touch locationInView:signatureImageView];
lastPoint.y -= 20;
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
mouseSwiped = YES;
UITouch *touch = [touches anyObject];
CGPoint currentPoint = [touch locationInView:signatureImageView];
currentPoint.y -= 20;
UIGraphicsBeginImageContext(signatureImageView.frame.size);
[signatureImageView.image drawInRect:CGRectMake(0, 0, signatureImageView.frame.size.width, signatureImageView.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapButt);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 1.0);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0.0, 0.0, 0.0, 1.0);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
signatureImageView.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
lastPoint = currentPoint;
mouseMoved++;
if (mouseMoved == 20) {
mouseMoved = 0;
}
}
- (void)clearsignatureImageView
{
signatureImageView.image = nil;
}
- (void)cancelsignatureImageView
{
[SignatureContentView setHidden:YES];
[signaturedImageView setHidden:NO];
}
- (void)getSignaturefromsignatureImageView
{
signaturedImageView.image=nil;
if (signatureImageView.image !=nil) {
AppDelegate *delegate =[AppDelegate sharedInstanceofAppdelegate];
UIGraphicsBeginImageContext(signatureImageView.frame.size);
[signatureImageView.image drawInRect:CGRectMake(0, 0, signatureImageView.frame.size.width, signatureImageView.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 1.0);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0.0, 0.0, 0.0, 1.0);
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
CGContextFlush(UIGraphicsGetCurrentContext());
signatureImageView.image = UIGraphicsGetImageFromCurrentImageContext();
// UIImageWriteToSavedPhotosAlbum(signatureImageView.image, nil, nil, nil);// black
UIGraphicsEndImageContext();
[SignatureContentView setHidden:YES];
[signaturedImageView setHidden:NO];
NSArray *docArr=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath =[NSString stringWithFormat:@"%@/%@",[docArr objectAtIndex:0],[NSString stringWithFormat:@"signature%@.png",[self PathNameforDocuments]]];
if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
[[NSFileManager defaultManager] removeItemAtPath:filePath error:nil];
}
filePath =[[docArr objectAtIndex:0] stringByAppendingPathComponent:[NSString stringWithFormat:@"signature%@.png",[self PathNameforDocuments]]];
NSData* pictureData = UIImagePNGRepresentation(signatureImageView.image);
BOOL success= [pictureData writeToFile:filePath atomically:YES ];
if (success) {
delegate.userSignatureImagePathString=filePath;
}
delegate.userSignatureImage=signatureImageView.image;
signaturedImageView =(UIImageView *)[self.view viewWithTag:imageViewSelectedTagvalue];
signaturedImageView.image=delegate.userSignatureImage;
}
else
{
// please sign
}
}
-(void)viewDidLoad
{
[self allocPopOverscreenforSignatureScreen];
}
使用UIGestureRecognizerDelegate委托并全局声明这些对象：
UIImageView *signatureImageView, *signaturedImageView;
BOOL mouseSwiped;
int mouseMoved;
UIView * SignatureContentView;