Use SVG Icons in wxWidgets C++ Applications

This guide shows how to use SVG icons in wxWidgets C++ apps, starting from clean SVGs exported with Axialis IconVectors. You will import SVG from a wxString or from an external file, convert to wxBitmap, and draw on screen.

What is wxWidgets? How SVG is handled

• Cross‑platform native GUI — Windows, macOS, and Linux using the platform’s native widgets for a natural look and feel.
• Open‑source and commercial‑friendly — uses the wxWidgets Library License; free for commercial apps.
• SVG in wxWidgets — modern versions provide wxBitmapBundle helpers: FromSVG() for in‑memory SVG (string) and FromSVGFile() for on‑disk SVG. Under the hood, a lightweight SVG rasterizer (NanoSVG) turns the vector into pixels at any size.
• Pros — crisp icons at any DPI; one vector source replaces many PNG sizes; simple API to obtain a wxBitmap.
• Cons — complex SVG filters/effects are out of scope; prefer simple paths, strokes, and flat fills for UI icons.
• Download — get wxWidgets from wxwidgets.org (source packages and links to package managers).

Export a clean SVG from IconVectors

1. Open or create your icon:
   • File → Open… (Ctrl+O) or New Icon (Ctrl+N).
   • Prefer a simple, single‑color shape with a clean viewBox (e.g., 0 0 24 24).

   

Option A — Inline SVG (wxString) ➜ wxBitmap with wxBitmapBundle::FromSVG

Use wxBitmapBundle::FromSVG() to create a scalable bundle from an SVG string, then request a wxBitmap for your target size and draw it.

#include <wx/wx.h>

static const char kSvg[] = R"SVG(
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path fill="none" 
stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" 
stroke-miterlimit="10" d="M14.8 3.4l1.9 2.3c.2 .2 .5 .4 .8 .4H20c1.1 0 2 .9 2 
2v10c0 1.1-.9 2-2 2H4c-1.1 0-2-.9-2-2V8c0-1.1 .9-2 2-2h2.5c.3 0 .6-.1 .8-.4l1.9-2.3
c.2-.2 .5-.4 .8-.4h4.1C14.3 3 14.6 3.1 14.8 3.4zM8.5 12.5c0 1.9 1.6 3.5 3.5 3.5
s3.5-1.6 3.5-3.5s-1.6-3.5-3.5-3.5S8.5 10.6 8.5 12.5z"/></svg>
)SVG";

class MyApp : public wxApp {
public:
  bool OnInit() override {
    auto* frame = new wxFrame(nullptr, wxID_ANY, "SVG in wxWidgets (FromSVG)", wxDefaultPosition, wxSize(260,180));

    // Build a scalable bundle from an in-memory SVG
    wxBitmapBundle bundle = wxBitmapBundle::FromSVG(kSvg, wxSize(24,24));
    wxBitmap bmp = bundle.GetBitmapFor(wxSize(24,24)); // request target size

    frame->Bind(wxEVT_PAINT, [frame, bmp](wxPaintEvent&){
      wxPaintDC dc(frame);
      dc.DrawBitmap(bmp, 40, 40, /*useMask=*/true);
    });

    frame->Show();
    return true;
  }
};
wxIMPLEMENT_APP(MyApp);

Tip: For HiDPI, compute the target size with frame->FromDIP(wxSize(24,24)) before calling GetBitmapFor().

Option B — External file ➜ wxBitmap with wxBitmapBundle::FromSVGFile

Load an SVG from disk (e.g., icons/check.svg packaged with your app), get a wxBitmap, and draw it.

#include <wx/wx.h>

class MyApp : public wxApp {
public:
  bool OnInit() override {
    auto* frame = new wxFrame(nullptr, wxID_ANY, "SVG in wxWidgets (FromSVGFile)", wxDefaultPosition, wxSize(260,180));

    wxString path = wxT("icons/check.svg");
    wxBitmapBundle bundle = wxBitmapBundle::FromSVGFile(path, wxSize(24,24));
    wxBitmap bmp = bundle.GetBitmapFor(wxSize(24,24));

    frame->Bind(wxEVT_PAINT, [frame, bmp](wxPaintEvent&){
      wxPaintDC dc(frame);
      dc.DrawBitmap(bmp, 40, 40, /*useMask=*/true);
    });

    frame->Show();
    return true;
  }
};
wxIMPLEMENT_APP(MyApp);

Notes & troubleshooting

• Requirements — use a recent wxWidgets (3.2+ recommended) with SVG support enabled. On some setups, SVG helpers depend on NanoSVG at build time.
• HiDPI — request bitmaps via GetBitmapFor(frame->FromDIP(size)) so the rasterized size matches the monitor scale.
• Keep SVG simple — prefer paths/fills/strokes; avoid advanced filters. Export minified SVG from IconVectors.