IOS resize or reposition line on touching end points (Objective c) -

i trying resize line, touching red circle points. let's say, want move line above lips in image below, how can achieve this. line not moving position. have started thing , can't find relevant resources accomplish this. trying best...please guide me in right direction. below code , reference image.

objective c code:

- (void)viewdidload {     [super viewdidload];     uibezierpath *path = [uibezierpath bezierpathwitharccenter:cgpointmake(100, 100) radius:10 startangle:0 endangle:6.2831853 clockwise:true];      //add second circle     [path movetopoint:cgpointmake(100.0, 100.0)];     [path addlinetopoint:cgpointmake(200, 200)];     [path movetopoint:cgpointmake(200, 200)];      [path addarcwithcenter:cgpointmake(200, 200) radius:10 startangle:0 endangle:6.2831853 clockwise:true];       [path closepath];     [[uicolor redcolor] setstroke];     [[uicolor redcolor] setfill];     [path stroke];     [path fill];      cashapelayer *shapelayer = [cashapelayer layer];     shapelayer.path = [path cgpath];     shapelayer.strokecolor = [[uicolor bluecolor] cgcolor];     shapelayer.linewidth = 2.0;     shapelayer.fillcolor = [[uicolor redcolor] cgcolor];      [self.view.layer addsublayer:shapelayer];  } 

i add multiple lines , ultimate aim move individual line @ position in image , measurement of area using line size.

edit: scenario is, @ given time there flexible lines available on screen. lets's clicking button, 1 more new line added screen. user can drag end point resize line in direction. can't thing working correctly.. no luck.

here gist file link, https://gist.github.com/akhildave/3a8bec5b4df95cc06822 adds uiview create line on image. code in gist allows me resize line height moving touch points , down doesn't allow me rotate angle of line , adding text in centre. thanks

thanks!

one of previous answers can extended include features you're trying implement. need implement 2 classes: lineview , lineimageview.

before start, take @ animated gif of finished demo.

note "add line" button added in storyboard , not subview of image view. create button, style it, , hook ibaction calls [self.lineimageview addlineview].

uiviewcontroller subclass implementation

#import "viewcontroller.h" #import "lineimageview.h"  @interface viewcontroller ()  @property (weak, nonatomic) iboutlet lineimageview *lineimageview;  @end  @implementation viewcontroller  - (void)viewdidload {     [super viewdidload]; }  - (ibaction)addlinetapped:(uibutton *)sender {     [self.lineimageview addlineview]; }  @end 

lineview interface

#import <uikit/uikit.h>  @interface lineview : uiview  @property (nonatomic) cgpoint startpoint; @property (nonatomic) cgpoint endpoint; @property (nonatomic) cgfloat circleradius; // defaults 30.0  @end 

lineview implementation

#import "lineview.h"  @interface lineview ()  @property (nonatomic) bool startpointtracking; @property (nonatomic) bool endpointtracking;  @end  @implementation lineview  - (instancetype)init {     self = [super init];     if (self) {         [self setup];     }     return self; }  - (instancetype)initwithcoder:(nscoder *)coder {     self = [super initwithcoder:coder];     if (self) {         [self setup];     }     return self; }  - (instancetype)initwithframe:(cgrect)frame {     self = [super initwithframe:frame];     if (self) {         [self setup];         self.startpoint = [self randompointinbounds];         self.endpoint = [self randompointinbounds];         [self setneedsdisplay];     }     return self; }  - (void)setup {     self.backgroundcolor = [uicolor clearcolor];     self.multipletouchenabled = false; // multi-touch not allowed     self.circleradius = 30.0; }  #pragma mark - touch handling  - (void)touchesbegan:(nsset *)touches withevent:(uievent *)event {     uitouch *touch = [touches anyobject];     cgpoint location = [touch locationinview:self];      if ([self pointisonstartcircle:location]) {         self.startpointtracking = yes;         self.endpointtracking = no;     } else if ([self pointisonendcircle:location]) {         self.startpointtracking = no;         self.endpointtracking = yes;     }      [self updatepointswithtouches:touches]; }  - (void)touchesmoved:(nsset *)touches withevent:(uievent *)event {     [self updatepointswithtouches:touches]; }  - (void)touchesended:(nsset *)touches withevent:(uievent *)event {     self.startpointtracking = no;     self.endpointtracking = no; }  - (void)touchescancelled:(nsset *)touches withevent:(uievent *)event {     self.startpointtracking = no;     self.endpointtracking = no; }  - (void)updatepointswithtouches:(nsset *)touches {     uitouch *touch = [touches anyobject];      if (self.startpointtracking) {         self.startpoint = [touch locationinview:self];         [self setneedsdisplay];      } else if (self.endpointtracking) {         self.endpoint = [touch locationinview:self];         [self setneedsdisplay];     } }  - (bool)pointinside:(cgpoint)point withevent:(nullable uievent *)event {     return [self pointisonstartcircle:point] || [self pointisonendcircle:point]; }  #pragma mark - drawing  - (void)drawrect:(cgrect)rect {     if ([self ishidden]) { return; }      [self drawtouchcircleatpoint:self.startpoint];     [self drawtouchcircleatpoint:self.endpoint];     [self drawlinebetweenfirstpoint:self.startpoint end:self.endpoint];     [self drawdistancetext]; }  - (void)drawlinebetweenfirstpoint:(cgpoint)startpoint end:(cgpoint)endpoint {     cgcontextref context = uigraphicsgetcurrentcontext();     cgcontextsavegstate(context);     cgcontextsetstrokecolorwithcolor(context, [[[uicolor whitecolor] colorwithalphacomponent:0.6] cgcolor]);     cgcontextsetlinewidth(context, 1.0);      cgcontextmovetopoint(context, startpoint.x, startpoint.y);     cgcontextaddlinetopoint(context, endpoint.x, endpoint.y);     cgcontextstrokepath(context);     cgcontextrestoregstate(context); }  - (void)drawtouchcircleatpoint:(cgpoint)circlepoint {     cgcontextref context = uigraphicsgetcurrentcontext();     cgcontextsavegstate(context);     cgcontextsetlinewidth(context, 2.0);     cgcontextsetrgbfillcolor(context, 1.0, 1.0, 1.0, 0.6);      cgcontextaddarc(context, circlepoint.x, circlepoint.y, self.circleradius, 30.0,  m_pi * 2, yes);     cgcontextfillpath(context);     cgcontextrestoregstate(context); }  - (void)drawdistancetext {     cgpoint midpoint = [self midpointbetweenfirstpoint:self.startpoint secondpoint:self.endpoint];      uifont *font = [uifont boldsystemfontofsize:18.0];     uicolor *textcolor = [uicolor whitecolor];     nsdictionary *attributes = @{nsfontattributename : font, nsforegroundcolorattributename : textcolor};     nsstring *distancestring = [self formatteddistancestring];      nsattributedstring *attributedstring = [[nsattributedstring alloc] initwithstring:distancestring attributes:attributes];      [attributedstring drawatpoint:midpoint]; }  #pragma mark - helper methods  - (cgpoint)randompointinbounds {     int x = arc4random() % (int)cgrectgetwidth(self.bounds);     int y = arc4random() % (int)cgrectgetheight(self.bounds);     return cgpointmake(x, y); }  - (cgfloat)distancefrompoint:(cgpoint)p1 topoint:(cgpoint)p2 {     cgfloat xdist = p2.x - p1.x;     cgfloat ydist = p2.y - p1.y;     return sqrt((xdist * xdist) + (ydist * ydist)); }  - (cgpoint)midpointbetweenfirstpoint:(cgpoint)p1 secondpoint:(cgpoint)p2 {     cgfloat x = (p1.x + p2.x) / 2.0;     cgfloat y = (p1.y + p2.y) / 2.0;     return cgpointmake(x, y); }  - (bool)pointisonstartcircle:(cgpoint)point {     cgfloat distance = [self distancefrompoint:point topoint:self.startpoint];     return distance <= self.circleradius; }  - (bool)pointisonendcircle:(cgpoint)point {     cgfloat distance = [self distancefrompoint:point topoint:self.endpoint];     return distance <= self.circleradius; }  - (nsstring *)formatteddistancestring {     cgfloat distance = [self distancefrompoint:self.startpoint topoint:self.endpoint];     nsnumberformatter *formatter = [[self class] sharedformatter];     return [formatter stringfromnumber:@(distance)]; }  + (nsnumberformatter *)sharedformatter {     static nsnumberformatter *sharedformatter = nil;     static dispatch_once_t oncetoken;     dispatch_once(&oncetoken, ^{         sharedformatter = [[nsnumberformatter alloc] init];     });     return sharedformatter; } 

lineimageview interface

#import <uikit/uikit.h>  @interface lineimageview : uiimageview  - (void)addlineview;  @end 

lineimageview implementation

#import "lineimageview.h" #import "lineview.h"  @interface lineimageview ()  @property (nonatomic, strong) nsmutablearray *lineviews; // of lineview  @end  @implementation lineimageview  - (instancetype)initwithframe:(cgrect)frame {     self = [super initwithframe:frame];     if (self) {         [self setup];     }     return self; }  - (instancetype)initwithcoder:(nscoder *)coder {     self = [super initwithcoder:coder];     if (self) {         [self setup];     }     return self; }  - (void)setup {     self.userinteractionenabled = yes; }  - (void)addlineview {     lineview *lineview = [[lineview alloc] initwithframe:self.bounds];     [self addsubview:lineview];     [self.lineviews addobject:lineview]; }