Question

Signature.h文件

#import <UIKit/UIKit.h>

@interface Signature : UIViewController
{

    CGPoint firstTouch;
    CGPoint lastTouch;
    UIColor *pointColor;
    CGRect *points;
    int npoints;
    CGPoint location;
   // UIImageView *signatureImageView;
}
 @property CGPoint firstTouch;
@property CGPoint lastTouch;
@property (nonatomic, retain) UIColor *pointColor;
@property CGRect *points;
@property int npoints;

@property (retain, nonatomic) IBOutletCollection(UIImageView) NSArray *drawSign;
@property CGPoint location;

@property (retain, nonatomic) IBOutletCollection(UIImageView) NSArray *signatureImageView;
- (IBAction)savePressed:(id)sender;
- (IBAction)clearPressed:(id)sender;

@end

Signature.m

#import "Signature.h"

@interface Signature ()

@end

@implementation Signature
@synthesize drawSign;
@synthesize signatureImageView;
@synthesize firstTouch;
@synthesize lastTouch;
@synthesize  pointColor;
@synthesize  points;


- (id)initWithFrame:(CGRect)frame
{
    return self;
}


- (id)initWithCoder:(NSCoder *)coder
{
    if(self = [super initWithCoder:coder])
    {
        self.npoints = 0;
    }
    return self;
}

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    NSLog(@"initwithnibname");
    return self;
}

- (void)viewDidLoad
{
    NSLog(@"viewdidload");

    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
}

- (void)viewDidUnload
{
    NSLog(@"view did unload");

    [self setSignatureImageView:nil];
    [self setDrawSign:nil];
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    NSLog(@"touch has began");

    UITouch *touch = [touches anyObject];
    self.location = [touch locationInView:self.view];
}

- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    NSLog(@"touches moves");

    UITouch *touch = [touches anyObject];
    CGPoint currentLocation = [touch locationInView:self.view];
   UIGraphicsBeginImageContext(self.view.frame.size);
    CGContextRef ctx = UIGraphicsGetCurrentContext();

  //[self.drawSign.image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
    CGContextSetLineCap(ctx, kCGLineCapRound);
    CGContextSetLineWidth(ctx, 5.0);
    CGContextSetRGBStrokeColor(ctx, 1.0, 0.0, 0.0, 1.0);
    CGContextBeginPath(ctx);
    CGContextMoveToPoint(ctx, location.x, location.y);
    NSLog(@"%f x is",location.x);
     NSLog(@"%f y is",location.y);
    CGContextAddLineToPoint(ctx, currentLocation.x, currentLocation.y);
    CGContextStrokePath(ctx);
   // self.image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    location = currentLocation;
}

- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    NSLog(@"touches ended");

    UITouch *touch = [touches anyObject];
  CGPoint currentLocation = [touch locationInView:self.view];

   UIGraphicsBeginImageContext(self.view.frame.size);
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    //[self.view.image drawInRect:CGRectMake(0, 0, self.frame.view.size.width, self.frame.view.size.height)];
    CGContextSetLineCap(ctx, kCGLineCapRound);
    CGContextSetLineWidth(ctx, 5.0);
    CGContextSetRGBStrokeColor(ctx, 1.0, 0.0, 0.0, 1.0);
    CGContextBeginPath(ctx);
    CGContextMoveToPoint(ctx, location.x, location.y);
   CGContextAddLineToPoint(ctx, currentLocation.x, currentLocation.y);
    CGContextStrokePath(ctx);
  //  self.image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    location = currentLocation;
} 

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (void)dealloc {
    [signatureImageView release];
    [super dealloc];
}
- (IBAction)savePressed:(id)sender {
    NSLog(@"save pressed");

}

- (IBAction)clearPressed:(id)sender {
    NSLog(@"cancel pressed");

}
@end

请找到与我的项目相关的两个文件。从一个观点来看，我正在接受这种观点。现在我需要保存用户绘制的内容。我能够获取坐标但无法绘制它们。我尝试了几次尝试，但它们似乎都没有工作。请以评论的方式在 Signature.m 文件中找到它们。请指出我的错误并纠正我。

Answer 1

我真的不明白你的问题，但这个代码错误的原因在于接触部分。

如果您想在触摸时绘制，则必须使用要绘制的视图中的drawInRect方法。

如果你想在用户发布图像后绘制图像以保存或显示它，那么你必须在 touchesBegan 上创建一个图像上下文，然后在 touchesMoved上绘制它，最后将结果保存在 touchesEnded 。

中

您可以使用

在 touchesEnded 中提取结果

UIImage *result = UIGraphicsGetImageFromCurrentImageContext();

您的代码现在正在做的是，每次移动手指时，您都会创建一个新画布，在其上绘制并销毁它。当你抬起手指时，你会再创建一个画布并将其销毁。

但我非常确定你想要移动手指并直接在屏幕上显示结果。为此，我真的建议你谷歌的教程，但基本上你必须：在触摸开始创建一个点数组，触摸移动你添加点到这个数组，在触摸结束时，你添加最后一个点到数组。 MEANWHILE在视图drawInRect上你的代码必须不断地在这个数组中绘制点。

编辑：

假设您在开头有一个有效的UIImage（blanc画布已初始化）的 self.drawSign.image

尝试：

- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { NSLog(@"touches moves"); UITouch *touch = [touches anyObject]; CGPoint currentLocation = [touch locationInView:self.view]; UIGraphicsBeginImageContext(self.view.frame.size); CGContextRef ctx = UIGraphicsGetCurrentContext(); [self.drawSign.image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)]; CGContextSetLineCap(ctx, kCGLineCapRound); CGContextSetLineWidth(ctx, 5.0); CGContextSetRGBStrokeColor(ctx, 1.0, 0.0, 0.0, 1.0); CGContextBeginPath(ctx); CGContextMoveToPoint(ctx, location.x, location.y); NSLog(@"%f x is",location.x); NSLog(@"%f y is",location.y); CGContextAddLineToPoint(ctx, currentLocation.x, currentLocation.y); CGContextStrokePath(ctx); self.drawSign.image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); location = currentLocation; } - (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { NSLog(@"touches ended"); UITouch *touch = [touches anyObject]; CGPoint currentLocation = [touch locationInView:self.view]; UIGraphicsBeginImageContext(self.view.frame.size); CGContextRef ctx = UIGraphicsGetCurrentContext(); [self.drawSign.image drawInRect:CGRectMake(0, 0, self.frame.view.size.width, self.frame.view.size.height)]; CGContextSetLineCap(ctx, kCGLineCapRound); CGContextSetLineWidth(ctx, 5.0); CGContextSetRGBStrokeColor(ctx, 1.0, 0.0, 0.0, 1.0); CGContextBeginPath(ctx); CGContextMoveToPoint(ctx, location.x, location.y); CGContextAddLineToPoint(ctx, currentLocation.x, currentLocation.y); CGContextStrokePath(ctx); self.drawSign.image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); location = currentLocation; }

我不确定这是否有效，但即使这样做也是一种可行的方式（表现明智）。

如何将坐标转换为图像

1 个答案: