Re: Drawing a lot of SVG images is slow

Hello,


Igor> What platform are you on?


I'm on Windows 10 and 11.


Igor> What wx version?


I'm using  the version cloned directly from git. It isn't the very 
latest one, as I haven't updated it for a couple months, but I don't 
think it would change much.


Igor> Are you working with Debug build?


I mostly observe the same slugginess, whether I'm using the debug build 
or not.

I'm compiling with MinGW-W64 / GCC 13 in 64 bits.


Igor> Choosing wxWidgets for the game is kind of weird - are you sure 
about that?


Yes I'm completely sure. It isn't weird at all, because it allows quite 
easily to make the game accessible to screen readers and zoom software, 
among others. This is my special particularity.

Most interactions are done via usual widgets (lists, buttons, grids, 
etc.), which makes it well suited to a GUI framework like WXWidgets. 
It's not at all a videogame in 3D.


Thank you.



Le 01.04.2025 à 20:27, Igor Korot a écrit :
> Hi,
> Sorry for top-posting, but…
>
> What platform are you on?
> What wx version?
> Are you working with Debug build?
> Choosing wxWidgets for the game is kind of weird - are you sure about 
> that?
>
> Thank you.
>
> On Tue, Apr 1, 2025 at 12:36 PM Quentin Cosendey 
> <[email protected]> wrote:
>
>     Hello,
>
>     I'm developing a game. I'm trying to use SVG images to draw the board
>     and all game elements (tokens, dice, etc.).
>     I wanted to use SVG because it allows the board to be seen all at
>     once
>     and have its size adapted to the size of the window, i.e. fill the
>     window as much as possible / make the board as big as possible,
>     without
>     pixelization effects. It also allows the user to customize the
>     color of
>     some game elements (for example tokens) quite easily, as well as
>     select
>     their own colors to make their own dark or high-contrast mode. All
>     this
>     is good for visually impaired players.
>
>     However, displaying everything (~1000 elements) seems to be quite
>     slow,
>     and it makes the interface lagging globally. It takes hundreds of
>     milliseconds to update the screen after having pressed a key and/or
>     moved the mouse.
>     Am I doing something wrong ? Do you have ideas on how I could improve
>     performances ?
>
>     Drawing code looks as follows, I have tried to simplify it a little:
>
>     void GameWindow::OnPaint (wxPaintEvent& e) {
>        wxAutoBufferedPaintDC dc(this);
>        std::unique_ptr<wxGraphicsContext>
>     g(wxGraphicsContext::Create(dc));
>          ...
>        for (auto& square: squares) {
>          wxRect pos = ... ; // boundaries of the square
>          g->ResetClip();
>          g->Clip(pos);
>          for (std::string& image: square.getElements()) {
>            auto bundle = app.getImage(image);
>            wxSize defaultSize = bundle.GetDefaultSize();
>            wxSize finalImageSize =
>     calcGreatestPossibleSize(wxSize(pos.width, pos.height), defaultSize);
>            auto bitmap = bundle.GetBitmap(finalImageSize);
>            if (bitmap.IsOk()) {
>              finalImageSize = bitmap.GetSize();
>              g->DrawBitmap(bitmap, pos.x, pos.y, finalImageSize.x,
>     finalImageSize.y);
>            }
>          }
>          g->ResetClip();
>        }
>     }
>
>
>     Loading code: wxImageBundle are stored in a
>     std::unordered_map<std::string, wxImageBundle> .
>     Using a simple array instead of the map and indexing images by index
>     instead of by name doesn't make a lot of difference, I have
>     already tested.
>
>     wxBitmapBundle App::getImage (const std::string& name) {
>        auto it = images.find(name);
>        if (it!=images.end()) return it->second;
>        wxString svgfn = "images/" + name + ".svg";
>        if (!svgfn.size()) return wxBitmapBundle(); // not found, return
>     empty bundle
>        wxSize imSize = readSVGImageSize(svgfn);
>        auto bundle = wxBitmapBundle::FromSVGFile(svgfn, imSize);
>        images[name] = bundle;
>        return bundle;
>     }
>
>     The SVG images used are extremely simple for the moment, there are no
>     complex things: basic shapes, polygons, polylines, paths; plain
>     fill and
>     stroke colors, no gradients or stuff like that.
>     Most squares have always the same size if the window isn't resized.
>
>     In case it can make a difference, GameWindows extends wxControl,
>     wxVarHVScrollHelper, wxAccessible
>
>     Where could the problem be ?
>
>     As far as I understand, the method wxImageBundle::GetBitmap basically
>     renders the SVG in a traditional in-memory bitmap. Is that really
>     necessary ? Isn't there a more direct way to draw SVG images ?
>     The documentation says that generated bitmaps are cached, so since
>     the
>     size don't change unless the window is resized, it shouldn't be a
>     problem, right ?
>
>     Is SVG support in WX just not made for that kind of thing ?
>     In this case do you have an alternate SVG library integrable with
>     WX to
>     advise ?
>
>     Thank you very much for your answers !
>
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