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# ThorVG

<p align="center">
  <img width="500" height="346" src="https://github.com/Samsung/thorvg/blob/master/res/thorvg_card2.png">
</p>

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. <br />
<br />
The next list shows drawing primitives ThorVG providing.<br />
 - 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, ... 
<p align="center">
  <img width="930" height="473" src="https://github.com/Samsung/thorvg/blob/master/res/example_primitives.png">
</p>
<br />
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.<br />
<br />
<p align="center">
  <img width="900" height="288" src="https://github.com/Samsung/thorvg/blob/master/res/example_flow.png">
</p>
<br />
 
## Contents
- [Building ThorVG](#building-thorvg)
	- [Meson Build](#meson-build)
- [Quick Start](#quick-start)
- [SVG](#svg)
- [Examples](#examples)
- [Tools](#tools)
	- [ThorVG Viewer](#thorvg-viewer)
	- [SVG to PNG](#svg-to-png)
- [API Bindings](#api-bindings)
- [Issues or Feature Requests?](#issues-or-feature-requests)

[](#contents)
<br />
## Building ThorVG
Basically, ThorVG supports [meson](https://mesonbuild.com/) build system.
<br />
### Meson Build
Install [meson](http://mesonbuild.com/Getting-meson.html) and [ninja](https://ninja-build.org/) if not already installed.

Run meson to configure ThorVG.
```
meson build
```
Run ninja to build & install ThorVG.
```
ninja -C build install
```
[Back to contents](#contents)
<br />
<br />
## 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.

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

You can prepare a empty canvas for drawing on it.

```cpp
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.

```cpp
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.

<p align="center">
  <img width="416" height="411" src="https://github.com/Samsung/thorvg/blob/master/res/example_shapes.png">
</p>

Or you can draw pathes with dash stroking.

```cpp
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.

<p align="center">
  <img width="300" height="300" src="https://github.com/Samsung/thorvg/blob/master/res/example_path.png">
</p>

Now begin rendering & finish it at a particular time.

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

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

Lastly, terminate the engine after usage.

```cpp
tvg::Initializer::term(tvg::CanvasEngine::Sw);
```
[Back to contents](#contents)
<br />
<br />
## SVG

ThorVG supports SVG(Scalable Vector Graphics) rendering through its own SVG interpreter. It basically aims to satisfy with [SVG Tiny Specification](https://www.w3.org/TR/SVGTiny12/) 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.

```cpp
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.

<p align="center">
  <img width="300" height="300" src="https://github.com/Samsung/thorvg/blob/master/res/example_tiger.png">
</p>

[Back to contents](#contents)
<br />
<br />
## 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](https://enlightenment.org/) for more information.

[Back to contents](#contents)
<br />
<br />
## Tools
### ThorVG Viewer
[ThorVG viewer](https://samsung.github.io/thorvg.viewer) supports immediate rendering through your browser. You can drag & drop SVG files on the page, see the rendering result on the spot.

[Back to contents](#contents)
<br />
<br />
### 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
```
[Back to contents](#contents)
<br />
<br />
## API Bindings
Our main development APIs are written in C++ but ThorVG also provides API bindings such as: C.

[Back to contents](#contents)
<br />
<br />
## Issues or Feature Requests?
For immediate assistant or support please reach us in [Gitter](https://gitter.im/thorvg/community)
