ios - UIBezierPath & CAShapeLayer initial animation jump -

-

i built company: https://github.com/busycm/bzystroketimer , during course of building, noticed interesting "bug" can't seem mitigate when using uibezierpath. right when animation starts, path jumps number of pixels forward (or backwards depending if it's counterclockwise) instead of starting smooth, incremental animation. , found that's interesting how path jumps forward value of line width cashaperlayer.

so example, if bezier path starts off @ cgrectgetmidx(self.bounds) , line 35, animation starts cgrectgetmidx(self.bounds)+35 , larger line width, more noticeable jump is. there way rid of path smoothly animate out start point?

here's picture of first frame. looks after animation starts. enter image description here

then when resume animation , pause again, distance moved 1/100th of distance see in picture.

here's bezier path code:

- (uibezierpath *)generatepathwithxinset:(cgfloat)dx withyinset:(cgfloat)dy clockwise:(bool)clockwise{     uibezierpath *path = [uibezierpath bezierpath];     [path movetopoint:cgpointmake(cgrectgetmidx(self.bounds)+dx/2, dy/2)];     [path addlinetopoint:cgpointmake(cgrectgetmaxx(self.bounds)-dx/2, dy/2)];     [path addlinetopoint:cgpointmake(cgrectgetmaxx(self.bounds)-dx/2, cgrectgetmaxy(self.bounds)-dy/2)];     [path addlinetopoint:cgpointmake(dx/2, cgrectgetmaxy(self.bounds)-dy/2)];     [path addlinetopoint:cgpointmake(dx/2, dy/2)];     [path closepath];     return clockwise ? path : [path bezierpathbyreversingpath]; }

here's animation code:

cabasicanimation *wind = [self generateanimationwithduration:self.duration == 0 ? kdefaultduration : self.duration fromvalue:@(self.shapelayer.strokestart) tovalue:@(self.shapelayer.strokeend) withkeypath:keypath withfillmode:kcafillmodeforwards]; wind.timingfunction = [camediatimingfunction functionwithname:self.timingfunction]; wind.removedoncompletion = no; self.shapelayer.path = [self generatepathwithxinset:self.linewidth withyinset:self.linewidth clockwise:self.clockwise].cgpath; [self.shapelayer addanimation:wind forkey:@"strokeendanimation"];

and here's how construct cashapelayer.

- (cashapelayer *)shapelayer {     return !_shapelayer ? _shapelayer = ({         cashapelayer *layer = [cashapelayer layer];         layer.linewidth = kdefaultlinewidth;         layer.fillcolor = uicolor.clearcolor.cgcolor;         layer.strokecolor = [uicolor blackcolor].cgcolor;         layer.linecap = kcalinecapsquare;         layer.frame = self.bounds;         layer.strokestart = 0;         layer.strokeend = 1;         layer;     }) : _shapelayer; }

i think what's happening here that, in frame of animation, drawing line consists of single point. since line has thickness associated it, , line cap type kcalinecapsquare, that'll rendered square height , width equal line width.

you can think of if drawing line square marker, , going drag midpoint of marker goes through every point in curve specified. first point in line, it's if marker touches down @ point, leaving square behind.

here's visual representation different line cap types make more intuitive. should change line cap style kcalinecapbutt.

sidenote: after make change, in line of code

[path movetopoint:cgpointmake(cgrectgetmidx(self.bounds)+dx/2, dy/2)];

you don't have offset x coordinate dx/2 anymore.


Comments

Post a Comment

Popular posts from this blog

qt - Using float or double for own QML classes -

-
i've created components , helper methods using c++ , qt used in qml gui. of methods calculate gui elements (size, transformations, scene graph items creation). target arm 32 bit using opengl / eglfs render output. opengl using float , qml using real (defined double ). what should use in c++ do not lose precision? if use qreal ( double ) shouldn't lose precision. if git grep float in qtbase.git , can find out bit more: dist/changes-5.2.0-**************************************************************************** dist/changes-5.2.0-* important behavior changes * dist/changes-5.2.0-**************************************************************************** dist/changes-5.2.0- dist/changes-5.2.0- - qt compiled qreal typedef'ed double on dist/changes-5.2.0: platforms. qreal float on arm chipsets before. guarantees more dist/changes-5.2.0- consistent behavior between platforms qt supports, binary dist/chan...
Read more

Create Outlook appointment via C# .Net -

-
i need create outlook appointment using microsoft.office.interop.outlook , while can work locally on own workstation , works if run web application via server's browser, not work when connect server externally. hence, think might permission issue. i changed application pool identity " localsystem " don't access denied error. unfortunately, doesn't work. the app behaves if appointment created, appointment doesn't appear in outlook. here include file on top of aspx.cs page using outlook = microsoft.office.interop.outlook; here code using pop appointment. outlook.application apptapp = new outlook.application(); outlook.appointmentitem appt = apptapp.createitem(outlook.olitemtype.olappointmentitem) outlook.appointmentitem; appt.subject = txtfirstname.text + " " + txtlastname.text; appt.body = txtcomment.text; appt.alldayevent = false; appt.start = datetime.parse(txtreminderdate.text + " 8:00 am"); appt.end = datetime.p...
Read more

ios - Swift Array Resetting Itself -

-
i have 2 arrays: pointhistory , datehistory . have nstimer , , when timer runs out, action called. in action appending int pointhistory , , current date string datehistory . here timer action: func timeraction() { let steppervalue = int(stepper.value) employee.numberofpoints = steppervalue networking.saveemployee(employee, completion: { (error) -> void in if error != nil { let alert = uialertcontroller(title: "error", message: "there error updating \(self.employee.name)'s points", preferredstyle: .alert) let alertaction = uialertaction(title: "ok", style: .cancel, handler: nil) alert.addaction(alertaction) self.presentviewcontroller(alert, animated: true, completion: nil) } }) var dateformatter = nsdateformatter() dateformatter.dateformat = "mm-dd-yyyy" dateformatter.timezone = nstimezone.localtimezone() var date = nsdate() var ...
Read more