GitHub - bibhas2/svglib

What is It?

svglib is a SVG file parser and renderer library for Windows. It uses Direct2D for GPU assisted rendering and XMLLite for XML parsing. They are core components of Windows. You don't need to download any external libraries to compile and distribute applications that use svglib.

Why?

This is meant for Win32 applications and games to easily display SVG images. Just enough of the SVG spec is covered for the library to be useful in most situations.

Build Instructions

You will need Visual Studio Community Edition with C++ language support.

Clone this repo.

git clone git@github.com:bibhas2/svglib.git

Clone mgui. This is used by some of the test applications only and not by svglib.

git clone git@github.com:bibhas2/mgui.git

Open the solution svglib/svglib.sln in Visual Studio Community Edition and build the solution.

Using svglib

Include the header file svglib.h. Link with the static library svglib.lib.

You will also need to link with Direct2D, Direct3D, DirectWrite etc. This is best done by adding these lines to one of the C++ files of your application.

#pragma comment(lib, "D3D11.lib")
#pragma comment(lib, "d2d1.lib")
#pragma comment(lib, "xmllite.lib")
#pragma comment(lib, "dwrite.lib")

Finally, enable support for C++ 17 for your project.

Minimal Code Example

For each HWND to be used to display a SVG, you need a SVGDevice.

SVGDevice device;
HWND m_wnd = ...;

//Setup the device
bool status = device.init(m_wnd);

//Check status

Each SVG image is reprsented by a SVGImage. We can load an image like this.

SVGImage image;

if (SVG::load(L"file.svg", device, image)) {
    //Force a WM_PAINT event
	device.redraw();
}
else {
	//Show error message
}

Render the image from the WM_PAINT handler of the window.

bool handle_event(UINT message, WPARAM wParam, LPARAM lParam) {
    switch (message) {
    case WM_PAINT:
        PAINTSTRUCT ps;

        //Call BeginPaint and EndPaint, or else we will get continuous
        //WM_PAINT messages.
        BeginPaint(m_wnd, &ps);

        //Clear the device with a white background
        SVG::clear(device);
        //Render the SVG
        SVG::render(device, image);

        EndPaint(m_wnd, &ps);
        break;
    case WM_SIZE:
        //Resize the device area
        device.resize();
        break;
    case WM_ERASEBKGND:
        //Handle background erase to avoid flickering 
        //during resizing and move
        break;
    default:
        //...
    }

    return true;
}

Technical Notes

Direct2D and DirectWrite pretty much map the SVG spec 1:1. This made writing svglib fairly trivial. The only exception is textPath. I have no plans to support textPath.

clipPath is also not supported at this time. But, a support is planned in the future.

Security and Vulnerability

Always make sure that the SVGDevice was initialized properly. Using a half initialized device can cause unpredicatble results. The library does not validate the device when it's used later to load and render images.

The SVG image files must be trusted. Please note:

• No protection is provided by the library for depth limit for recursive XML structures.
• No overflow check is done for the coordinate values in the SVG file.