Is there an SDK to draw lines on iOS with touch?

Question

Is there a framework I can use to draw lines with touch. Basically I want to add ability for a customer to sign on iPad/iPhone and capture it as an image.

Any help much appreciated.

Thanks.

Answer 1

you can meet your requirement by using core graphics available in UIKIT framework.

i had a similar requirement in my application with a different use ,if needed i can provide you the code.

TNQ

.h file

#import <UIKit/UIKit.h>
typedef enum _DrawingMode{
DrawingModePen =0,
DrawingModeEraser=1,
} DrawingMode;
@interface DrawingView : UIView {
CGPoint lastPoint;
UIImageView *drawImage;
BOOL mouseSwiped;   
int mouseMoved;
DrawingMode mode;
UIColor *_drawingPenColor;
}
@property (nonatomic, retain) UIColor *drawingPenColor;
@property (nonatomic) DrawingMode mode;

@property (nonatomic, retain) UIImageView *imageView;
@property (nonatomic,retain)UIImageView *drawImage;
@end

.m

#import "DrawingView.h"


@implementation DrawingView

@synthesize mode, drawingPenColor=_drawingPenColor, imageView=drawImage;


-(void)initialize{
    drawImage = [[UIImageView alloc] initWithImage:nil];
    self.autoresizesSubviews = YES;
    drawImage.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
    drawImage.frame = self.bounds;
    [self addSubview:drawImage];
    self.backgroundColor = [UIColor clearColor];
    mouseMoved = 0;
    _drawingPenColor = [[UIColor alloc] initWithWhite:0.0 alpha:1.0];
}

-(void)maskImage:(UIImage *)image withMask:(UIImage *)maskImage 
{
    CGImageRef maskRef = maskImage.CGImage; 
    CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
                                        CGImageGetHeight(maskRef),
                                        CGImageGetBitsPerComponent(maskRef),
                                        CGImageGetBitsPerPixel(maskRef),
                                        CGImageGetBytesPerRow(maskRef),
                                        CGImageGetDataProvider(maskRef), NULL, false);
    CGImageRef masked = CGImageCreateWithMask([image CGImage], mask);
    UIImage *tempImage = [[UIImage alloc] initWithCGImage:masked];
    //self.clippedImage = tempImage;
    [tempImage release];
    CFRelease(masked);
    CFRelease(mask);
}

-(void)awakeFromNib{
    [self initialize];
}

- (id)initWithFrame:(CGRect)frame {
    if ((self = [super initWithFrame:frame])) {
        // Initialization code
        [self initialize];
    }
    return self;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    mouseSwiped = NO;
    UITouch *touch = [touches anyObject];

    if ([touch tapCount] == 2) {
        drawImage.image = nil;
        return;
    }

    lastPoint = [touch locationInView:self];
    //lastPoint.y -= 20;
    NSLog(@"touches begin");

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    mouseSwiped = YES;

    UITouch *touch = [touches anyObject];   
    CGPoint currentPoint = [touch locationInView:self];
    //currentPoint.y -= 20;


    UIGraphicsBeginImageContext(self.bounds.size);
    [drawImage.image drawInRect:CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height)];
    CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
    CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0);
    if (mode == DrawingModePen) {
        NSLog(@"drawing");
        CGContextSetStrokeColorWithColor(UIGraphicsGetCurrentContext(), [_drawingPenColor CGColor]);
    }
    else {
        CGContextSetStrokeColorWithColor(UIGraphicsGetCurrentContext(), [[UIColor clearColor] CGColor]);

        CGContextBeginPath(UIGraphicsGetCurrentContext());


        CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
        CGContextClearRect (UIGraphicsGetCurrentContext(), CGRectMake(lastPoint.x, lastPoint.y, 20, 20));
        CGContextStrokePath(UIGraphicsGetCurrentContext());

        NSLog(@"clearing");
            }
    CGContextBeginPath(UIGraphicsGetCurrentContext());
    CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
    CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
    CGContextStrokePath(UIGraphicsGetCurrentContext());
    drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    lastPoint = currentPoint;

    mouseMoved++;

    if (mouseMoved == 10) {
        mouseMoved = 0;
    }

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

    UITouch *touch = [touches anyObject];

    if ([touch tapCount] == 2) {
        drawImage.image = nil;
        return;
    }


    if(!mouseSwiped) {
        UIGraphicsBeginImageContext(self.bounds.size);
        [drawImage.image drawInRect:CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height)];
        CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
        CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0);
        CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
        CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
        if (mode == DrawingModePen) {
            CGContextSetStrokeColorWithColor(UIGraphicsGetCurrentContext(), [_drawingPenColor CGColor]);
        }
        else {
            CGContextSetStrokeColorWithColor(UIGraphicsGetCurrentContext(), [self.backgroundColor CGColor]);
        }
        CGContextStrokePath(UIGraphicsGetCurrentContext());
        CGContextFlush(UIGraphicsGetCurrentContext());
        drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
    }
}

- (void)dealloc {
    [drawImage release];
    [_drawingPenColor release];
    [super dealloc];
}

@end