Synfig File format

Revision as of 21:58, 1 February 2016

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A .sif file is the XML representation of a canvas. It holds the canvas's metadata, such as width and height, as well as information about its layers. Typically, a Synfig production comprises many .sif files joined in a sequence or nested within each other.

The .sif format is formidably complex and evolving. It is implementation-defined rather than spec-defined. Therefore, you should take everything on this page with a grain of salt. Indeed, the implementation can change at any point.

There are no plans to freeze the format.

Source code

The .sif format is implemented by the following file:

https://github.com/synfig/synfig/blob/master/synfig-core/src/synfig/loadcanvas.cpp

Concepts

Linking / Exporting

.sif files aren't always self-contained. They can link to parts of other .sif files, which creates a dependency of one on the other. This may seem strange to animators who use Flash because, in Flash, animation files are usually self-contained.

One drawback of Synfig's approach is that .sif dependencies are hard to track. A tool called RenderChan solves this problem.

Recursion

Recursion of .sif files is prohibited.

Compression

Synfig recognizes .sifz as the extension of gzip-compressed .sif files. New and alternate implementations of .sif are urged to support this compression, although it is not required.

<canvas>

Overview

The top element of a .sif file is always a <canvas>.

<?xml version="1.0"?>

<canvas version="0.1" width="300" height="350" xres="2952.7559"
        yres="2952.7559" view-box="-1.5 2.5 1.5 -1" antialias="2"
        fps="12" begin-time="0f" end-time="0f" bgcolor="0.5 0.5 0.5 1">
    ...
</canvas>

Inside a <canvas> you can find the following elements:

• <name>
• <meta>
• <author>
• <desc>
• <layer>
• <defs>
• <bones>
• <keyframe>

<name>

The short name of the canvas.

<canvas version="0.1">
    ...
    <name>Aqua Sphere</name>
    ...
</canvas>

<meta>

Metadata for the Synfig Studio editor. These can be safely ignored by other implementations.

<canvas version="0.1">
    ...
    <meta name="grid_show" content="1" />
    ...
</canvas>

Synfig Studio recognizes these <meta> names (source):

• grid_size
• grid_color
• grid_snap
• grid_show
• onion_skin
• onion_skin_past
• onion_skin_future
• guide_color
• guide_snap
• guide_show
• guide_x
• guide_y
• sketch
• solid_lines
• background_size
• background_first_color
• background_second_color

<author>

The name of the canvas's author.

<canvas version="0.1">
    ...
    <author>King Arthur</author>
    ...
</canvas>

<desc>

A human-readable description of the canvas.

<canvas version="0.1">
    ...
    <desc>This aqua-colored sphere reminds me of something from Mac OS X.</desc>
    ...
</canvas>

<layer>

Overview

Layers describe the shapes and effects on a canvas.

<canvas version="0.1">
    ...
    <layer type="solid_color" version="0.1"
    ...
</canvas>

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