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https://github.com/adobe/svg-native-viewer

SVG Native viewer is a library that parses and renders SVG Native documents
https://github.com/adobe/svg-native-viewer

cpp opentype-svg-fonts svg svg-icons svg-native

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SVG Native viewer is a library that parses and renders SVG Native documents

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README 

        
# SVG Native Viewer



[![CircleCI](https://circleci.com/gh/adobe/svg-native-viewer.svg?style=svg)](https://circleci.com/gh/adobe/svg-native-viewer)



SVG Native viewer is a library that parses and renders SVG Native

documents.



## SVG Native

SVG Native is an upcoming specification of the SVG WG based on [SVG

OpenType](https://docs.microsoft.com/en-us/typography/opentype/spec/svg)

. SVG Native will be a strict subset of SVG 1.1 and SVG 2.0.



### Supported features in SVG Native (in comparison to SVG1.1/SVG2)

* No stylesheet support (CSS/XSL) with the exception of the basic

inheritance model and the following presentation attributes:

    * `clip-path`

    * `clip-rule`

    * `color`

    * `display`

    * `fill`

    * `fill-opacity`

    * `fill-rule`

    * `opacity`

    * `stroke`

    * `stroke-dasharray`

    * `stroke-dashoffset`

    * `stroke-linecap`

    * `stroke-linejoin`

    * `stroke-miterlimit`

    * `stroke-opacity`

    * `stroke-width`

    * `stop-color`

    * `stop-opacity`

    * `visibility`

* CSS properties do not support any default property values like

  `inherit`, `initial`, `unset`, or `revert`.

* No support for scripting, interactions, events, animations, filters,

  masks, patterns, texts.

* No support for inner `` or `` elements.

* No support for XML namespaces with the exception of the SVG namespace

  and the Xlink namespace.

* No support of `objectBoundingBox` on `gradientUnits` or

  `clipPathUnits`.

* The `var()` CSS value function is limited to the CSS properties

  `fill`, `stroke`, `stop-color` and `color`. Only color values are

  allowed. `currentColor` is supported.



A valid SVG Native document is always a valid SVG1.1/2.0 document.



## SVG Native Viewer Library



SVG Native Viewer is a C++11 based project and can either be included

in the source code of a client directly or linked statically or

dynamically.



For rendering, SVG Native Viewer requires a rendering port. Already

existing ports include:

* **StringSVGRenderer** for testing purposes,

* **CGSVGRenderer** a rendering port using CoreGraphics (Quartz 2D).

* **SkiaSVGRenderer** a rendering port using Skia. (**Skia requires a C++14 compatible compiler!**)

* **CairoSVGRenderer** a rendering port using Cairo Graphics.

* **GDIPlusSVGRenderer** a rendering port using GDI+.

* **D2DSVGRenderer** a rendering port using Direct2D.



New ports need to inherit from **SVGRenderer** and implement the

virtual functions.



Here an example how to use SVG Native Viewer with Skia

**SkiaSVGRenderer**:



```cpp

// Create the renderer object

auto renderer = std::make_shared();



// Create SVGDocument object and parse the passed SVG string.

auto doc = std::unique_ptr

(SVGNative::SVGDocument::CreateSVGDocument(svgInput.c_str(), renderer));



// Setup SkSurface for drawing

auto skRasterSurface = SkSurface::MakeRasterN32Premul(doc->Width(),

                                                      doc->Height());

auto skRasterCanvas = skRasterSurface->getCanvas();



// Pass SkCanvas to renderer object

renderer->SetSkCanvas(skRasterCanvas);



// Pass drawing commands for SVG document to renderer.

doc->Render();



// Pass drawing commands for SVG document to renderer the element (and

// its descendants)

// with the XML ID "ref1".

std::string id1{"ref1"}

doc->Render(id1);



// The Render() function may get called multiple times. This can be

// used to render a combination of glyphs specified in the same SVG

// document.

std::string id2{"ref2"}

doc->Render(id2);

```



Refer to the examples in the `example/` directory for other port

examples.



## Requirements

### Submodules



This repository uses submodules. To initiate and keep submodules

up-to-date run the following command:



```

git submodule update --init

```



Submodules are located in the `third_party/` directory. Used submodules:

* [stylesheet](https://github.com/adobe/stylesheet/tree/modifications)

  **(optional)** Needed if compiled with limited CSS style support

(deprecated).

* [cpp-base64](https://github.com/ReneNyffenegger/cpp-base64)

  **(optional)** Needed by some ports for decoding base64 encoded raster

image support.

* [boost_variant_property_tree](https://github.com/dirkschulze/boost_variant_property_tree)

  **(optional)** Minimal version of Boost stripped down to the

  requirements of `variant` and `property_tree`. Used if Boost was not

  installed on the system.



### Windows



Install:

* [CMake](https://cmake.org) Download and run the installer

* [Boost](https://www.boost.org) Download the ZIP-package and extract

  the package into `C:>\Program Files\boost_x.y.z\` (See below how to

  specify a different Boost installation directory by a CMake option.)

* [MS Visual Studio 2017 or

  up](https://visualstudio.microsoft.com/vs/whatsnew/) Download and

  install with the installer. Make sure Visual C++ gets installed. (You

  maybe be able to use the "Community" version for free for

  non-commercial/enterprise use. See the website from MS for license

  details.)



### OSX

With Homebrew:

```

brew install cmake

brew install llvm

brew install boost

```



### LINUX



* Apt

```

sudo apt-get install build-essential libboost-system-dev cmake

```



## Building



### Create project files



For Windows 64 bit:

```

cmake -Bbuild/win64 -H. -G "Visual Studio 15 2017 Win64"

```



For Windows 32 bit:

```

cmake -Bbuild/win32 -H. -G "Visual Studio 15 2017"

```

_Omit `-H` when running in PowerShell._



For macOS

```

cmake -Bbuild/mac -H. -G "Xcode"

```



For Linux

```

cmake -Bbuild/linux -H.

```

On Linux you may choose to use GCC or Clang/LLVM. Add the following to

the command above to choose between one and the other:

* `-DCMAKE_CXX_COMPILER=g++` for GCC

* `-DCMAKE_CXX_COMPILER=clang` for Clang/LLVM



On Windows you may choose to use Clang/LLVM as compiler. For help,

follow the instructions of the linked MS Visual Studio [LLVM

Extension](https://marketplace.visualstudio.com/items?itemName=LLVMExtensions.llvm-toolchain). 

Add ` -T "LLVM"` to the project generation command above.



To specify a different Boost installation directory on Windows use the

following command:

* `-DBOOST_ROOT=X:\path\to\boost`



The following arguments can be passed with the `-D` flag and the

options `ON` or `OFF`:

* `LIB_ONLY` Only compile the library without examples. Default `OFF`.

* `SHARED` If `ON`, builds a dynamic library. Static otherwise. Default

  `OFF`.

* `PLATFORM_XML` If `ON`, uses libxml2 or Epat if provided by the

  system. Otherwise RapidXML via boost. Default `OFF`.

* `TEXT` adds the _Text_ port to the library. Default `ON`.

* `CG` adds the _CoreGraphics/Quartz2D_ port to the library. Default

  `OFF`.

* `SKIA` adds the _Skia_ port to the library. Default `OFF`.

* `GDIPLUS` adds the _GDI+_ port to the library. Default `OFF`.

* `D2D` adds the _Direct2D_ port to the library. Default `OFF`.

* `CAIRO` adds the _Cairo Graphics_ port to the library. Default `OFF`.

* `TESTING` enables automated testing using Google Tests. Default `ON`.



To enable the deprecated CSS styling support:

* `STYLE` adds limited, deprecated support for `` element and

  `style` attribute. Default `OFF`. _(This option will get removed

  eventually.)_



The following example creates project files for the library with the

Text, CoreGraphics/Quartz2D and Skia port and the example applications.

**Example:**

```

cmake -Bbuild/mac -H. -G "Xcode" -DCG=ON -DSKIA=ON

```



**Note:** For testing, build with the `TEXT` option set to `ON` and

 `LIB_ONLY` option set to `OFF`. (The default for both.)



### Build



Replace `win64` with your platform (`mac` for Xcode on macOS)

```

cmake --build build/win64 --config Release

```



## Boost requirements



Only the header version of Boost is required. The following Boost

features are used:

* Boost RapidXML _(Can be replaced by libxml2.)_

* `boost::variant` to handle different SVG paint types of `fill` and

 `stroke` as well as different color value types.

* Boost string functions like `boost::tokenizer`, `boost::trim`. _(Only

used by deprecated CSS `<style>` element parsing.)_



## Tests

SVG Native Viewer has two testing mechanisms. A python script that performs the renderings on the *Text* port and compares the renderings with the existing ones and automated software testing using Google Tests framework. 



### *Text* port testing

To use the python script:

1. Make sure your system has Python installed.

2. By default, CMake creates the project files for

**SVGNativeViewerLib** and **testSVGNative**. Follow the steps above to

build the test app.

3. Run

  ```

  python script/runTest.py --tests=test/

  ```

  Here the argument list of **runTest.py**:

  * `--test` the folder with the test files.

  * `--program` the path to **testSVGNative**. If not provided uses the

    default, relative build path.

  * `--debug` Debug build or Release build of **testSVGNative**. Only

    relevant if `--program` was not set and defaults to `--debug`.

### Google Test based testing

In order to build and run the tests, pass the argument `-DTESTING=ON` when running Cmake. Cmake will automatically download and build Google Tests and compile the tests. In order to run the tests you can run `make test` or just use `ctest` in the build folder.



Ultimately, we aim to improve software unit testing as well as add rendering tests to ensure that SVG Native Viewer's renderings are accurate.



## Known limitations in SVG Native Viewer

* `preserveAspectRatio` is not supported on the `<svg>` element yet.

* Furthermore, there might be limitations on certain platforms. (E.g.

  missing gradient spread-method support on CoreGraphics.)



## Contributing



Contributions are welcomed! Read the [Contributing

Guide](./.github/CONTRIBUTING.md) for more information.



## Licensing



This project is licensed under the Apache V2 License. See

[LICENSE](LICENSE) for more information.