How to draw a line on top of an image when finger moves on iPhone -


i trying draw line on top of background image in uiview tracing movements of user's finger. can accomplish drawing uiimage background , doing line drawing in drawrect have load image each time drawrect called , makes performance sluggish. alternatively, if use uiimageview background image (just adding view in ib or programatically) lines disappear when dragged on image. there way tell lines draw on top of uiimageview. help.

here code using uiimage method:

- (void)drawrect:(cgrect)rect {     uiimage *imagefield = [uiimage imagenamed:@"field.jpg"];     cgrect rectforimage=cgrectmake(0,0,200,200);     [imagefield drawinrect:rectforimage];          cgcontextref context = uigraphicsgetcurrentcontext();         cgcontextmovetopoint(context, x1, y1);     cgcontextaddlinetopoint(context, x2, y2);     cgcontextstrokepath(context); }

adding image background view correct way it. problem lies in fact added image directly view. subviews displayed on top of view, not behind it. correctly use container view holds image view background, , line-drawing view on top of that.


Comments

Post a Comment

Popular posts from this blog

asp.net - repeatedly call AddImageUrl(url) to assemble pdf document -

i'm using abcpdf , i'm curious if can recursively call addimageurl() function assemble pdf document compile multiple urls? something like: int pagecount = 0; int theid = thedoc.addimageurl("http://stackoverflow.com/search?q=abcpdf+footer+page+x+out+of+", true, 0, true); //assemble document while (thedoc.chainable(theid)) { thedoc.page = thedoc.addpage(); theid = thedoc.addimagetochain(theid); } pagecount = thedoc.pagecount; console.writeline("1 document page count:" + pagecount); //flatten document (int = 1; <= pagecount; i++) { thedoc.pagenumber = i; thedoc.flatten(); } //now try again theid = thedoc.addimageurl("http://stackoverflow.com/questions/1980890/pdf-report-generation", true, 0, true); //assemble document while (thedoc.chainable(theid)) { thedoc.page = thedoc.addpage(); theid = thedoc.addimagetoc
Read more

java - Android recognize cell phone with keyboard or not? -

in android app, want detect user's device if device has keyboard(like motorola milestone) , show corresponding user interface. guys know how that? ! regards justicepenny http://developer.android.com/reference/android/content/res/configuration.html public int keyboard the kind of keyboard attached device. 1 of: keyboard_nokeys, keyboard_qwerty, keyboard_12key. that's it!
Read more

iphone - How would you achieve a LED Scrolling effect? -

how achieve led scrolling effect example below? led sign - led ticker emulator iphone , ipad http://img.skitch.com/20101201-rsfh4p1bajb1wp94k466pdpiuj.preview.jpg sometimes remunerates comment in other posts :) have put code you, should implement font '8pin matrix' realistic feeling. uilabel *label; - (void)viewdidload { [super viewdidload]; label = [[uilabel alloc]initwithframe:cgrectmake(10, 50, 300, 20)]; label.font = [uifont fontwithname:@"courier-bold" size:16.0]; label.backgroundcolor = [uicolor blackcolor]; label.textcolor = [uicolor greencolor]; label.linebreakmode = uilinebreakmodecharacterwrap; // otherwise "…" label.text = @"this led text scrolled "; // blanks space between [self.view addsubview:label]; [nstimer scheduledtimerwithtimeinterval:0.12f target:self selector:@selector(scrolllabel) use
Read more