Search Results

Search found 9889 results on 396 pages for 'pointer speed'.

Page 343/396 | < Previous Page | 339 340 341 342 343 344 345 346 347 348 349 350  | Next Page >

  • Images from url to listview

    - by Andres
    I have a listview which I show video results from YouTube. Everything works fine but one thing I noticed is that the way it works seems to be a bit slow and it might be due to my code. Are there any suggestions on how I can make this better? Maybe loading the images directly from the url instead of using a webclient? I am adding the listview items in a loop from video feeds returned from a query using the YouTube API. The piece of code which I think is slowing it down is this: Feed<Video> videoFeed = request.Get<Video>(query); int i = 0; foreach (Video entry in videoFeed.Entries) { string[] info = printVideoEntry(entry).Split(','); WebClient wc = new WebClient(); wc.DownloadFile(@"http://img.youtube.com/vi/" + info[0].ToString() + "/hqdefault.jpg", info[0].ToString() + ".jpg"); string[] row1 = { "", info[0].ToString(), info[1].ToString() }; ListViewItem item = new ListViewItem(row1, i); YoutubeList.Items.Add(item); imageListSmall.Images.Add(Bitmap.FromFile(info[0].ToString() + @".jpg")); imageListLarge.Images.Add(Bitmap.FromFile(info[0].ToString() + @".jpg")); } public static string printVideoEntry(Video video) { return video.VideoId + "," + video.Title; } As you can see I use a Webclient which downloads the images so then I can use them as image in my listview. It works but what I'm concerned about is speed..any suggestions? maybe a different control all together?

    Read the article

  • A public struct inside a class

    - by Koning Baard
    I am new to C++, and let's say I have two classes: Creature and Human: /* creature.h */ class Creature { private: public: struct emotion { /* All emotions are percentages */ char joy; char trust; char fear; char surprise; char sadness; char disgust; char anger; char anticipation; char love; }; }; /* human.h */ class Human : Creature { }; And I have this in my main function in main.cpp: Human foo; My question is: how can I set foo's emotions? I tried this: foo->emotion.fear = 5; But GCC gives me this compile error: error: base operand of '-' has non-pointer type 'Human' This: foo.emotion.fear = 5; Gives: error: 'struct Creature::emotion' is inaccessible error: within this context error: invalid use of 'struct Creature::emotion' Can anyone help me? Thanks P.S. No I did not forget the #includes

    Read the article

  • How to optimize paging for large in memory database

    - by snakefoot
    I have an application where the entire database is implemented in memory using a stl-map for each table in the database. Each item in the stl-map is a complex object with references to other items in the other stl-maps. The application works with a large amount of data, so it uses more than 500 MByte RAM. Clients are able to contact the application and get a filtered version of the entire database. This is done by running through the entire database, and finding items relevant for the client. When the application have been running for an hour or so, then Windows 2003 SP2 starts to page out parts of the RAM for the application (Eventhough there is 16 GByte RAM on the machine). After the application have been partly paged out then a client logon takes a long time (10 mins) because it now generates a page fault for each pointer lookup in the stl-map. I can see it is possible to tell Windows to lock memory in RAM, but this is generally only recommended for device drivers, and only for "small" amounts of memory. I guess a poor mans solution could be to loop through the entire memory database, and thus tell Windows we are still interested in keeping the datamodel in RAM. I guess another poor mans solution could be to disable the pagefile completely on Windows. I guess the expensive solution would be a SQL database, and then rewrite the entire application to use a database layer. Then hopefully the database system will have implemented means to for fast access. Are there other more elegant solutions ?

    Read the article

  • Computation overhead in C# - Using getters/setters vs. modifying arrays directly and casting speeds

    - by Jeffrey Kern
    I was going to write a long-winded post, but I'll boil it down here: I'm trying to emulate the graphical old-school style of the NES via XNA. However, my FPS is SLOW, trying to modify 65K pixels per frame. If I just loop through all 65K pixels and set them to some arbitrary color, I get 64FPS. The code I made to look-up what colors should be placed where, I get 1FPS. I think it is because of my object-orented code. Right now, I have things divided into about six classes, with getters/setters. I'm guessing that I'm at least calling 360K getters per frame, which I think is a lot of overhead. Each class contains either/and-or 1D or 2D arrays containing custom enumerations, int, Color, or Vector2D, bytes. What if I combined all of the classes into just one, and accessed the contents of each array directly? The code would look a mess, and ditch the concepts of object-oriented coding, but the speed might be much faster. I'm also not concerned about access violations, as any attempts to get/set the data in the arrays will done in blocks. E.g., all writing to arrays will take place before any data is accessed from them. As for casting, I stated that I'm using custom enumerations, int, Color, and Vector2D, bytes. Which data types are fastest to use and access in the .net Framework, XNA, XBox, C#? I think that constant casting might be a cause of slowdown here. Also, instead of using math to figure out which indexes data should be placed in, I've used precomputed lookup tables so I don't have to use constant multiplication, addition, subtraction, division per frame. :)

    Read the article

  • Create a variable which is named depending on an ID number?

    - by gray
    Is there any way to create a variable, and add an ID to the end of the actual variable name? I have a variable called 'gauge', used to create a new Gauge object: var gauge = new Gauge(target).setOptions(opts); I want to add an ID to the variable, so something like: var gauge+id = new Gauge(target).setOptions(opts); It's because I'm creating a number of these objects, and have a specific ID already for each one, which I want to attach to the gauge object if possible? All my code for this function is below, if it gives you a better idea of what i need to do: function go(id, votes) { var val = $('#votes_'+id).text(); var target = document.getElementById('foo_'+id); // your canvas element var gauge = new Gauge(target).setOptions(opts); // create sexy gauge! gauge.maxValue = 100; // set max gauge value gauge.animationSpeed = 20; // set animation speed (32 is default value) var a=votes+0.5; gauge.set(val); // set actual value } My main problem arises on the last line. It says gauge.set(val), and it only sets the last object, ignoring all the other ones...

    Read the article

  • How to mimic polymorphism in classes with template methods (c++)?

    - by davide
    in the problem i am facing i need something which works more or less like a polymorphic class, but which would allow for virtual template methods. the point is, i would like to create an array of subproblems, each one being solved by a different technique implemented in a different class, but holding the same interface, then pass a set of parameters (which are functions/functors - this is where templates jump up) to all the subproblems and get back a solution. if the parameters would be, e.g., ints, this would be something like: struct subproblem { ... virtual void solve (double& solution, double parameter)=0; } struct subproblem0: public subproblem { ... virtual void solve (double& solution, double parameter){...}; } struct subproblem1: public subproblem { ... virtual void solve (double* solution, double parameter){...}; } int main{ subproblem problem[2]; subproblem[0] = new subproblem0(); subproblem[1] = new subproblem1(); double argument0(0), argument1(1), sol0[2], sol1[2]; for(unsigned int i(0);i<2;++i) { problem[i]->solve( &(sol0[i]) , argument0); problem[i]->solve( &(sol1[i]) , argument1); } return 0; } but the problem is, i need the arguments to be something like Arg<T1,T2> argument0(f1,f2) and thus the solve method to be something of the likes of template<T1,T2> solve (double* solution, Arg<T1,T2> parameter) which cant obviously be declared virtual ( so cant be called from a pointer to the base class)... now i'm pretty stuck and don't know how to procede...

    Read the article

  • Advice: Python Framework Server/Worker Queue management (not Website)

    - by Muppet Geoff
    I am looking for some advice/opinions of which Python Framework to use in an implementation of multiple 'Worker' PCs co-ordinated from a central Queue Manager. For completeness, the 'Worker' PCs will be running Audio Conversion routines (which I do not need advice on, and have standalone code that works). The Audio conversion takes a long time, and I need to co-ordinate an arbitrary number of the 'Workers' from a central location, handing them conversion tasks (such as where to get the source files, or where to ask for the job configuration) with them reporting back some additional info, such as the runtime of the converted audio etc. At present, I have a script that makes a webservice call to get the 'configuration' for a conversion task, based on source files located on the worker already (we manually copy the source files to the worker, and that triggers a conversion routine). I want to change this, so that we can distribute conversion tasks ("Oy you, process this: xxx") based on availability, and in an ideal world, based on pending tasks too. There is a chance that Workers can go offline mid-conversion (but this is not likely). All the workers are Windows based, the co-ordinator can be WIndows or Linux. I have (in my initial searches) come across the following - and I know that some are cross-dependent: Celery (with RabbitMQ) Twisted Django Using a framework, rather than home-brewing, seems to make more sense to me right now. I have a limited timeframe in which to develop this functional extension. An additional consideration would be using a Framework that is compatible with PyQT/PySide so that I can write a simple UI to display Queue status etc. I appreciate that the specifics above are a little vague, and I hope that someone can offer me a pointer or two. Again: I am looking for general advice on which Python framework to investigate further, for developing a Server/Worker 'Queue management' solution, for non-web activities (this is why DJango didn't seem the right fit).

    Read the article

  • What is the fastest way to check if files are identical?

    - by ojblass
    If you have 1,000,0000 source files, you suspect they are all the same, and you want to compare them what is the current fasted method to compare those files? Assume they are Java files and platform where the comparison is done is not important. cksum is making me cry. When I mean identical I mean ALL identical. Update: I know about generating checksums. diff is laughable ... I want speed. Update: Don't get stuck on the fact they are source files. Pretend for example you took a million runs of a program with very regulated output. You want to prove all 1,000,000 versions of the output are the same. Update: read the number of blocks rather than bytes? Immediatly throw out those? Is that faster than finding the number of bytes? Update: Is this ANY different than the fastest way to compare two files?

    Read the article

  • jQuery slideToggle jump on close

    - by spankmaster79
    Hi, I'm trying to slideToggle a in a table with jQuery and it works in FF, OP, CHrome. Only IE (6,7,8) is giving me problems. It slides down perfectly down and up, but after the slide up animation is finished. The hidden pops up in full height and then closes. So I guess it must be somwhere inbetween when it switches from a minimal height to "display:none" that it appears for a short second. The code is built dynamically but I'll try to give an example: <table> <tr> <td> <script type="text/javascript"> function toggleTr_{$dynamicID}() { $('#content_{$dynamicID}').slideToggle('slow'); /* DO SOME OTHER STOFF LIKE COLOR CHANGES CSS CLASS CHANGES */ } </script> </td> </tr> <tr id="list_{$dynamicID}" onclick="toggleTr_{$dynamicID}();" style="cursor:pointer;"> <td> <!-- INFO HEADER --> </td> </tr> <tr> <td> <div id="content_{$dynamicID}" style="display:none;"> <!-- INFO BODY HIDDEN --> </div </td> </tr> Other problems here with slideToggle only descibed problems with padding, margin, or problems with the animation, but that all works. Help is appreciated. Thx, Spanky

    Read the article

  • null terminating a string

    - by robUK
    Hello, gcc 4.4.4 c89 just wondering what is the standard way to null terminate a string. i.e. However, when I use the NULL I get the warning message. *dest++ = 0; *dest++ = '\0'; *dest++ = NULL; /* Warning: Assignment takes integer from pointer without a cast */ source code I am using: size_t s_strscpy(char *dest, const char *src, const size_t len) { /* Copy the contents from src to dest */ size_t i = 0; for(i = 0; i < len; i++) *dest++ = *src++; /* Null terminate dest */ *dest++ = 0; return i; } Just another quick question. I deliberately commented out the line that null terminates. However, it still correctly printed out the contents of the dest. The caller of this function would send the length of the string by either included the NULL or not. i.e. strlen(src) + 1 or stlen(src). size_t s_strscpy(char *dest, const char *src, const size_t len) { /* Copy the contents from src to dest */ size_t i = 0; /* Don't copy the null terminator */ for(i = 0; i < len - 1; i++) *dest++ = *src++; /* Don't add the Null terminator */ /* *dest++ = 0; */ return i; } Many thanks for any advice,

    Read the article

  • Correct way to switch between UIView with ARC. My way leads to memory leaks :( (iOS)

    - by Andrei Golubev
    i use xcode 4.4 with ARC on.. I have dynamically created UIViews in the ViewController.m: UIView*myviews[10]; Then in the - (void)viewDidLoad function i fill each of it with pictures i need myviews[viewIndex] = [[UIView alloc]initWithFrame:myrec]; UIImage *testImg; UIImageView * testImgView; testImg = [UIImage imageNamed:[NSString stringWithFormat:@"imgarray%d.png", viewIndex]; testImgView.image = testImg; viewindex++; So all seems to be fine, when i want to jump from one view to another i do with two buttons next: [self.view addSubview:views[viewIndex]]; CATransition *animation = [CATransition animation]; [animation setDelegate:self]; [animation setDuration:1.0f]; [animation setType:@"rippleEffect"]; [animation setSubtype:kCATransitionFromTop]; //[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]]; [self.view.layer addAnimation:animation forKey:@"transitionViewAnimation"]; Nothing seems to be bad, but the memory consumption grows with huge speed when i switch between views.. and then i get low memory warning or sometimes application will just crash. I have tried to use UIViewController array and was switching between the controllers: nothing changes, the memory low warning is what i end up with.. Maybe i need to clean the memory somehow? But how? ARC does not allow to use release and so on.. last what i have tried (sorry, maybe not very professional) before to add new subview is this NSArray *viewsToRemove = [self.view subviews]; for (UIView *views in viewsToRemove) { [views removeFromSuperview]; } But this does not help either.. Please don't judge too strong, i am still new to iOS and Objective-c..

    Read the article

  • Problem using a COM interface as parameter

    - by Cesar
    I have the following problem: I have to projects Project1 and Project2. In Project1 I have an interface IMyInterface. In Project2 I have an interface IMyInterface2 with a method that receives a pointer to IMyInterface1. When I use import "Project1.idl"; in my Project2.idl, a #include "Project1.h" appears in Project2___i.h. But this file does not even exist!. What is the proper way to import an interface defined into other library into a idl file? I tried to replace the #include "Project1.h" by *#include "Project1_i.h"* or *#include "Project1_i.c"*, but it gave me a lot of errors. I also tried to use importlib("Project1.tlb") and define my interface IMyInterface2 within the library definition. But when I compile Project2PS project, an error is raised (something like dlldata.c is not generated if no interface is defined). I tried to create a dummy Project1.h. But when Project2___i.h is compiled, compiler cannot find MyInterface1. And if I include Project1___i.h I get a lot of errors again! Apparently, it is a simple issue, but I don't know how to solve it. I'm stuck with that!. By the way, I'm using VS2008 SP1. Thanks in advance.

    Read the article

  • Difference between MVC FilterAttribute and Filter

    - by zaaaaphod
    I'm trying to write my own custom AuthorizationAttribute that uses DI. I'm using the MUNQ IoC provider for it's speed and have decided to use constructor injection on all my classes as opposed to post instatiation property binding (because I prefer it). I'm trying to write a custom IFilterProvider that will use my IoC container to return requests for filters (so that I can map concrete classes using the container). I've come up with the following. public class FilterProvider : IFilterProvider { private readonly IocContainer _container; public FilterProvider(IocContainer container) { _container = container; } public IEnumerable<Filter> GetFilters(ControllerContext controllerContext, ActionDescriptor actionDescriptor) { var x = Enumerable.Union<Object>(_container.ResolveAll<IActionFilter>(), _container.ResolveAll<IAuthorizationFilter>()); foreach (Filter actionFilter in x) yield return new Filter(actionFilter, FilterScope.First, null); } } The above code will fail during the foreach because my objects that implement IAuthorizationFilter are based on FilterAttribute and not Filter My question is, what is the difference between Filter and FilterAttribute? I would have thought that there would have been a common link between them, unless I'm missing something. Another deeper question is, how come there is no IFilterAttributeProvider that would support IEnumerable GetFilters(...) Is there some other way that I should be using to resolve IAuthorizationFilter via my IoC container? Thank you very much for your help. Z

    Read the article

  • Setting up a view to draw to in Objective-C (iPhone) ?

    - by Johannes Jensen
    Okay, so, I'm all new to iPhone and stuff, but I'm not even at programming, I have many years of experience with ActionScript 2.0 and 3.0, I want to set up a view, that I can also pass variables to. The view is gonna draw everything with Quartz. I tried to make another game where I tried to add a pointer to a NSMutableArray to the view class, but it didn't work cause I didn't know how to store an actual class. I wanted to do like: [myView setNeedsDisplay]; but I had to do [(View*)self.view setNeedsDisplay]; didn't really work out in the end... Okay, so now I got: - (void) viewDidLoad { [super viewDidLoad]; viewClass = [[View class] retain]; gameView = [[[viewClass alloc] initWithFrame: CGRectZero] retain]; [gameView setNeedsDisplay]; } This is in my drawInContext:context, which is fired by drawRect: Also, my drawRect does [self drawInContext: UIGraphicsGetCurrentContext()]; CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]); CGContextSetLineWidth(context, 3.0); CGContextSetLineCap(context, kCGLineCapRound); CGContextSetLineJoin(context, kCGLineJoinRound); CGMutablePathRef aPath = CGPathCreateMutable(); CGPathMoveToPoint(aPath, nil, 5, 5); CGPathAddLineToPoint(aPath, nil, 45, 43); CGContextAddPath(context, aPath); CGContextStrokePath(context); Nothing happens. Help? Oh yeah, I get this error: : invalid context for each time I use those functions. :[ Thanks!

    Read the article

  • Lite-Javascript Gallery - Can I position the img absolutely in relationship to the lis?

    - by blackessej
    I have a lite-javascript run image gallery. The javascript grabs each element in the list and places it as a background in the parent element. Then the CSS styles the thumbnails as small blocks with a defined height/width. A click-event for each object toggles it’s child’s element’s visibility and adds an “active” class name to the . Using CSS, I'm trying to place the absolutely to make it appear at the same position for each thumb, but it's moving in relation to the thumbs. Here's the CSS: #jgal li { background-position:50% 50%; background-repeat:no-repeat; border:solid #999 4px; cursor:pointer; display:block; float:left; height:60px; width:60px; margin-bottom:14px; margin-right:14px; opacity:0.5; } #jgal li img { position:absolute; top:0px; left:210px; display:none; } And the site: http://www.erisdesigns.net Thanks in advance for any help!

    Read the article

  • simple image animation with the keyboard

    - by conorhiggins
    Hi the app I am currently working on requires a simple animation to be performed, which I am able to do but timing is an issue. The app uses the slightly opaque keyboard and I have set up a black background to make it more visually pleasing . The app is a utility app and as the user clicks on a settings button the app will flip which looks great. However there is a problem at the moment in that while the app is flipping the keyboard also closes which itself looks great also, however the background remains. I was wondering if there was a way of animating the background image to follow the keyboard's animation pattern and speed? If I set up a discrete animation time the chances are there will be some sort of overlap and either the image will show too long or the keyboard will show too long. Any suggestions? Another option is to make the keyboard show constantly if anyone knows how to do that? i would rather animate it though as it is quite a simple app and so I would like to make it as aesthetically pleasing as possible. /Conor

    Read the article

  • C++ Dynamic Allocation Mismatch: Is this problematic?

    - by acanaday
    I have been assigned to work on some legacy C++ code in MFC. One of the things I am finding all over the place are allocations like the following: struct Point { float x,y,z; }; ... void someFunc( void ) { int numPoints = ...; Point* pArray = (Point*)new BYTE[ numPoints * sizeof(Point) ]; ... //do some stuff with points ... delete [] pArray; } I realize that this code is atrociously wrong on so many levels (C-style cast, using new like malloc, confusing, etc). I also realize that if Point had defined a constructor it would not be called and weird things would happen at delete [] if a destructor had been defined. Question: I am in the process of fixing these occurrences wherever they appear as a matter of course. However, I have never seen anything like this before and it has got me wondering. Does this code have the potential to cause memory leaks/corruption as it stands currently (no constructor/destructor, but with pointer type mismatch) or is it safe as long as the array just contains structs/primitive types?

    Read the article

  • Many users, many cpus, no delays. Good for cloud?

    - by Eric
    I wish to set up a CPU-intensive time-important query service for users on the internet. A usage scenario is described below. Is cloud computing the right way to go for such an implementation? If so, what cloud vendor(s) cater to this type of application? I ask specifically, in terms of: 1) pricing 2) latency resulting from: - slow CPUs, instance creations, JIT compiles, etc.. - internal management and communication of processes inside the cloud (e.g. a queuing process and a calculation process) - communication between cloud and end user 3) ease of deployment A usage scenario I am expecting is: - A typical user sends a query (XML of size around 1K) once every 30 seconds on average. - Each query requires a numerical computation of average time 0.2 sec and max time 1 sec on a 1 GHz Pentium. The computation requires no data other than the query itself and is performed by the same piece of code each time. - The delay a user experiences between sending a query and receiving a response should be on average no more than 2 seconds and in general no more than 5 seconds. - A background save to a DB of the response should occur (not time critical) - There can be up to 30000 simultaneous users - i.e., on average 1000 queries a second, each requiring an average 0.2 sec calculation, so that would necessitate around 200 CPUs. Currently I'm look at GAE Java (for quicker deployment and less IT hassle) and EC2 (Speed and price optimization) as options. Where can I learn more about the right way to set ups such a system? past threads, different blogs, books, etc.. BTW, if my terminology is wrong or confusing, please let me know. I'd greatly appreciate any help.

    Read the article

  • Data structure to build and lookup set of integer ranges

    - by actual
    I have a set of uint32 integers, there may be millions of items in the set. 50-70% of them are consecutive, but in input stream they appear in unpredictable order. I need to: Compress this set into ranges to achieve space efficient representation. Already implemented this using trivial algorithm, since ranges computed only once speed is not important here. After this transformation number of resulting ranges is typically within 5 000-10 000, many of them are single-item, of course. Test membership of some integer, information about specific range in the set is not required. This one must be very fast -- O(1). Was thinking about minimal perfect hash functions, but they do not play well with ranges. Bitsets are very space inefficient. Other structures, like binary trees, has complexity of O(log n), worst thing with them that implementation make many conditional jumps and processor can not predict them well giving poor performance. Is there any data structure or algorithm specialized in integer ranges to solve this task?

    Read the article

  • Which is the correct design pattern for my PHP application?

    - by user1487141
    I've been struggling to find good way to implement my system which essentially matches the season and episode number of a show from a string, you can see the current working code here: https://github.com/huddy/tvfilename I'm currently rewriting this library and want a nicer way to implement how the the match happens, currently essentially the way it works is: There's a folder with classes in it (called handlers), every handler is a class that implements an interface to ensure a method called match(); exists, this match method uses the regex stored in a property of that handler class (of which there are many) to try and match a season and episode. The class loads all of these handlers by instantiating each one into a array stored in a property, when I want to try and match some strings the method iterates over these objects calling match(); and the first one that returns true is then returned in a result set with the season and episode it matched. I don't really like this way of doing it, it's kind of hacky to me, and I'm hoping a design pattern can help, my ultimate goal is to do this using best practices and I wondered which one I should use? The other problems that exist are: More than one handler could match a string, so they have to be in an order to prevent the more greedy ones matching first, not sure if this is solvable as some of the regex patterns have to be greedy, but possibly a score system, something that shows a percentage of how likely the match is correct, i'd have no idea how to actually implement this though. I'm not if instantiating all those handlers is a good way of doing it, speed is important, but using best practices and sticking to design patterns to create good, extensible and maintainable code is my ultimate priority. It's worth noting the handler classes sometimes do other things than just regex matching, they sometimes prep the string to be matched by removing common words etc. Cheers for any help Billy

    Read the article

  • How does object of sub-class record information about its super-class the in a Virtual Inheritance

    - by Summer_More_More_Tea
    Hi there: I encounter this problem when tackling with virtual inheritance. I remember that in a non-virtual inheritance hierarchy, object of sub-class hold an object of its direct super-class. What about virtual inheritance? In this situation, does object of sub-class hold an object of its super-class directly or just hold a pointer pointing to an object of its super-class? By the way, why the output of the following code is: sizeof(A): 8 sizeof(B): 20 sizeof(C): 32 Code: #include <iostream> using namespace std; class A{ char k[ 3 ]; public: virtual void a(){}; }; class B : public virtual A{ char j[ 3 ]; public: virtual void b(){}; }; class C : public virtual B{ char i[ 3 ]; public: virtual void c(){}; }; int main( int argc, char *argv[] ){ cout << "sizeof(A): " << sizeof( A ) << endl; cout << "sizeof(B): " << sizeof( B ) << endl; cout << "sizeof(C): " << sizeof( C ) << endl; return 0; } Thanks in advance. Kind regards.

    Read the article

  • C++ design question, container of instances and pointers

    - by Tom
    Hi all, Im wondering something. I have class Polygon, which composes a vector of Line (another class here) class Polygon { std::vector<Line> lines; public: const_iterator begin() const; const_iterator end() const; } On the other hand, I have a function, that calculates a vector of pointers to lines, and based on those lines, should return a pointer to a Polygon. Polygon* foo(Polygon& p){ std::vector<Line> lines = bar (p.begin(),p.end()); return new Polygon(lines); } Here's the question: I can always add a Polygon (vector Is there a better way that dereferencing each element of the vector and assigning it to the existing vector container? //for line in vector<Line*> v //vcopy is an instance of vector<Line> vcopy.push_back(*(v.at(i)) I think not, but I dont really like that approach. Hopefully, I will be able to convince the author of the class to change it, but I cant base my coding right now to that fact (and i'm scared of a performance hit). Thanks in advance.

    Read the article

  • C++ design question, container of instances and pointers

    - by Tom
    Hi all, Im wondering something. I have class Polygon, which composes a vector of Line (another class here) class Polygon { std::vector<Line> lines; public: const_iterator begin() const; const_iterator end() const; } On the other hand, I have a function, that calculates a vector of pointers to lines, and based on those lines, should return a pointer to a Polygon. Polygon* foo(Polygon& p){ std::vector<Line> lines = bar (p.begin(),p.end()); return new Polygon(lines); } Here's the question: I can always add a Polygon (vector Is there a better way that dereferencing each element of the vector and assigning it to the existing vector container? //for line in vector<Line*> v //vcopy is an instance of vector<Line> vcopy.push_back(*(v.at(i)) I think not, but I dont really like that approach. Hopefully, I will be able to convince the author of the class to change it, but I cant base my coding right now to that fact (and i'm scared of a performance hit). Thanks in advance.

    Read the article

  • C++ design question, container of instances and pointers

    - by Tom
    Hi all, Im wondering something. I have class Polygon, which composes a vector of Line (another class here) class Polygon { std::vector<Line> lines; public: const_iterator begin() const; const_iterator end() const; } On the other hand, I have a function, that calculates a vector of pointers to lines, and based on those lines, should return a pointer to a Polygon. Polygon* foo(Polygon& p){ std::vector<Line> lines = bar (p.begin(),p.end()); return new Polygon(lines); } Here's the question: I can always add a Polygon (vector Is there a better way that dereferencing each element of the vector and assigning it to the existing vector container? //for line in vector<Line*> v //vcopy is an instance of vector<Line> vcopy.push_back(*(v.at(i)) I think not, but I dont really like that approach. Hopefully, I will be able to convince the author of the class to change it, but I cant base my coding right now to that fact (and i'm scared of a performance hit). Thanks in advance.

    Read the article

  • Image creation performance / image caching

    - by Kilnr
    Hello, I'm writing an application that has a scrollable image (used to display a map). The map background consists of several tiles (premade from a big JPG file), that I draw on a Graphics object. I also use a cache (Hashtable), to prevent from having to create every image when I need it. I don't keep everything in memory, because that would be too much. The problem is that when I'm scrolling through the map, and I need an image that wasn't cached, it takes about 60-80 ms to create it. Depending on screen resolution, tile size and scroll direction, this can occur multiple times in one scroll operation (for different tiles). In my case, it often happens that this needs to be done 4 times, which introduces a delay of more than 300 ms, which is extremely noticeable. The easiest thing for me would be that there's some way to speed up the creation of Images, but I guess that's just wishful thinking... Besides that, I suppose the most obvious thing to do is to load the tiles predictively (e.g. when scrolling to the right, precache the tiles to the right), but then I'm faced with the rather difficult task of thinking up a halfway decent algorithm for this. My actual question then is: how can I best do this predictive loading? Maybe I could offload the creation of images to a separate thread? Other things to consider? Thanks in advance.

    Read the article

< Previous Page | 339 340 341 342 343 344 345 346 347 348 349 350  | Next Page >