ThorVG

ThorVG is a platform-independent portable library for drawing vector-based shapes and images. It's written in C++, no dependencies and keeps super compact size.

The next list shows drawing primitives ThorVG providing.

• Paints: Line, Arc, Curve, Path, Shapes, Polygons
• Filling: Solid, Linear, Radial Gradient
• Scene Graph & Affine Transformation (translation, rotation, scale ...)
• Stroking: Width, Join, Cap, Dash
• Composition: Blending, Masking, Path Clipping, etc
• Pictures: SVG, PNG, Bitmap, ...

Basically your program could use this library functions by calling slick and neat apis while switching drawing context (if you have your own drawing engine), ThorVG serializes drawing commands among volatile paints node, performs sync/asynchronous rendering by its decent engines. The engine is suggested to immediate rendering method so that your system could adaptively integrate with it. ThorVG supports vector images such as SVG, also will support coming popular formats by demands. On rendering, it might introduce intermediate frame buffers for compositing vector scenes but only when it's necessary and these are temporarily used for saving memory. Next figure shows you a brief strategy how to use ThorVG in your system.

Contents

• Building ThorVG
  • Meson Build
• Quick Start
• SVG
• Examples
• Tools
  • ThorVG Viewer
  • SVG to PNG
• API Bindings
• Issues or Feature Requests?

Building ThorVG

Basically, ThorVG supports meson build system.

Meson Build

Install meson and ninja if not already installed.

Run meson to configure ThorVG.

meson build

Run ninja to build & install ThorVG.

ninja -C build install

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Quick Start

ThorVG renders vector shapes on a given canvas buffer. Here shows quick start to learn basic API usages.

First, You can initialize ThorVG engine.

tvg::Initializer::init(tvg::CanvasEngine::Sw, 0);   //engine method, thread count

You can prepare a empty canvas for drawing on it.

static uint32_t buffer[WIDTH * HEIGHT];          //canvas target buffer

auto canvas = tvg::SwCanvas::gen();              //generate a canvas
canvas->target(buffer, WIDTH, WIDTH, HEIGHT);    //stride, w, h

Next you can draw multiple shapes onto the canvas.

auto rect = tvg::Shape::gen();               //generate a round rectangle
rect->appendRect(50, 50, 200, 200, 20, 20);  //round geometry(x, y, w, h, rx, ry)
rect->fill(100, 100, 0, 255);                //round rectangle color (r, g, b, a)
canvas->push(move(rect));                    //push round rectangle drawing command

auto circle = tvg::Shape::gen();             //generate a circle
circle->appendCircle(400, 400, 100, 100);    //circle geometry(cx, cy, radiusW, radiusH)

auto fill = tvg::RadialGradient::gen();      //generate radial gradient for circle fill
fill->radial(400, 400, 150);                 //radial fill info(cx, cy, radius)

tvg::Fill::ColorStop colorStops[2];          //gradient color info
colorStops[0] = {0, 255, 255, 255, 255};     //index, r, g, b, a (1st color value)
colorStops[1] = {1, 0, 0, 0, 255};           //index, r, g, b, a (2nd color value)
fill.colorStops(colorStop, 2);               //set fil with gradient color info

circle->fill(move(fill));                    //circle color
canvas->push(move(circle));                  //push circle drawing command

This code result looks like this.

Or you can draw pathes with dash stroking.

auto path = tvg::Shape::gen();               //generate a path
path->moveTo(199, 34);                       //set sequential path coordinates
path->lineTo(253, 143);
path->lineTo(374, 160);
path->lineTo(287, 244);
path->lineTo(307, 365);
path->lineTo(199, 309);
path->lineTo(97, 365);
path->lineTo(112, 245);
path->lineTo(26, 161);
path->lineTo(146, 143);
path->close();

path->fill(150, 150, 255, 255);              //path color

path->stroke(3);                             //stroke width
path->stroke(0, 0, 255, 255);                //stroke color
path->stroke(tvg::StrokeJoin::Round);        //stroke join style
path->stroke(tvg::StrokeCap::Round);         //stroke cap style

float pattern[2] = {10, 10};
path->stroke(pattern, 2);                    //stroke dash pattern (line, gap)

canvas->push(move(path));                    //push path drawing command

This path drawing result shows like this.

Now begin rendering & finish it at a particular time.

canvas->draw();
canvas->sync();

Then you can acquire the rendered image from the buffer memory.

Lastly, terminate the engine after usage.

tvg::Initializer::term(tvg::CanvasEngine::Sw);

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SVG

ThorVG supports SVG(Scalable Vector Graphics) rendering through its own SVG interpreter. It basically aims to satisfy with SVG Tiny Specification for the lightweight system such as embeded. Most cases ThorVG supports the SVG spec fully but some partial SVG features were not supported officially yet. Next list shows the unsupported features by ThorVG.

• CSS Styles
• Filters
• Images

Next code snippet shows you how to draw SVG image using ThorVG.

auto picture = tvg::Picture::gen();         //generate a picture
picture->load("tiger.svg");                 //Load SVG file.
canvas->push(move(picture));                //push picture drawing command

And here is the result.

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Examples

There are various examples to understand ThorVG APIs, Please check sample code in thorvg/src/examples

To execute examples, you can build them with this meson option.

meson -Dexamples=true . build

Note that these examples are required EFL elementary package for launching. If you're using Linux-based OS, you could easily install its package from your OS distribution server. Otherwise, please visit the official EFL page for more information.

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Tools

ThorVG Viewer

ThorVG viewer supports immediate rendering through your browser. You can drag & drop SVG files on the page, see the rendering result on the spot.

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SVG to PNG

ThorVG provides an executable svg2png converter which generate a PNG file from a SVG file.

To use svg2png, you must turn on its feature in the build option.

meson -Dtools=svg2png . build

Alternatively, you can add svg2png value to tools option in meson_option.txt. Build output will be located in {builddir}/src/bin/svg2png/

For more information, see svg2png usages:

Usage: 
   svg2png [svgFileName] [Resolution] [bgColor]

Examples: 
    $ svg2png input.svg
    $ svg2png input.svg 200x200
    $ svg2png input.svg 200x200 ff00ff

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API Bindings

Our main development APIs are written in C++ but ThorVG also provides API bindings such as: C.

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Issues or Feature Requests?

For immediate assistant or support please reach us in Gitter