Data Guide #
The data structures are one of the most complex and important parts of Penpot. It's critical that the data integrity is always maintained throughout the whole usage, and also file exports & imports and data model evolution.
To modify the data structure (the most typical case will be to add a new attribute to the shapes), this list must be checked. This is not an exhaustive list, but all of this is important in general.
General considerations #
We prefer that the page and shape attributes are optional. I.E. there is a default object behavior, that occurs when the attribute is not present, and its presence activates some feature (example: if there is no
fill-color, the shape is not filled). When you revert to the default state, it's better to remove the attribute than leaving it with null value. There are some process (for example import & export) that filter out and remove all attributes that are null.
So never expect that attribute with null value is a different state that without the attribute.
In objects attribute names we don't use special symbols that are allowed by Clojure (for example ending it with ? for boolean values), because this may cause problems when exporting.
Specs and shapes creation #
▾ common/ ▾ src/app/common/ ▾ pages/ helpers.cljc init.cljc spec.cljc
spec.cljcwe have Clojure specs to validate the syntactic structure of objects inside a page.
init.cljcare the default values for newly created objects.
helpers.cljcthere are functions to help managing objects and doing transformations to them.
We are currently in process of refactoring this into
common/src/app/common/typesmodule, with a more Abstract Data Type oriented style.
Data migrations #
▾ common/ ▾ src/app/common/ ▾ pages/ common.cljc migrations.cljc
When changing the model it's essential to take into account that the existing Penpot files must keep working without changes. If you follow the general considerations stated above, usually this is automatic, since the objects already in the database just have the default behavior, that should be the same as before the change. And the new features apply to new or edited objects.
But if this is not possible and we are talking of a breaking change, you can
write a data migration. Just define a new data version and a migration script
migrations.cljc and increment
From then on, every time a file is loaded from the database, if its version number is lower than the current version in the app, the file data will be handled to all the needed migration functions. If you later modify and save the file, it will be now updated in database.
Shape edit forms #
▾ frontend/ ▾ src/ ▾ app/ ▾ main/ ▾ ui/ ▾ workspace/ ▾ sidebar/ ▾ options/ ▸ menus/ ▸ rows/ ▾ shapes/ bool.cljs circle.cljs frame.cljs group.cljs image.cljs multiple.cljs path.cljs rect.cljs svg_raw.cljs text.cljs
shapes/*.cljsthere are the components that show the edit menu of each shape type.
menus/*.cljsthere are the building blocks of these menus.
rows/*.cljsthere are some pieces, for example color input and picker.
Multiple edit #
When modifying the shape edit forms, you must take into account that these forms may edit several shapes at the same time, even of different types.
When more than one shape is selected, the form inside
multiple.cljs is used.
At the top of this module, a couple of maps define what attributes may be edited
and how, for each type of shape.
Then, the blocks in
menus/*.cljs are used, but they are not given a shape, but
a values map. For each attribute, if all shapes have the same value, it is taken;
if not, the attribute will have the value
The form blocks must be prepared for this value, display something useful to the user in this case, and do a meaningful action when changing the value. Usually this will be to set the attribute to a fixed value in all selected shapes, but only those that may have the attribute (for example, only text shapes have font attributes, or only rects has border radius).
Component synchronization #
▾ common/ ▾ src/app/common/ ▾ pages/ common.cljc
For all shape attributes, you must take into account what happens when a component is created, the attribute changed and then the component syncronized.
common.cljc there is a structure that maps shape attributes to sync
groups. When an attribute is changed, the group will be marked as touched in
the shape, and when syncing all the attributes in the group will be copied.
Any attribute that is not in this map will be ignored in synchronizations.
Export & import #
▾ frontend/ ▾ src/ ▾ app/ ▾ main/ ▾ ui/ ▾ shapes/ ▸ text/ attrs.cljs bool.cljs circle.cljs custom_stroke.cljs embed.cljs export.cljs fill_image.cljs filters.cljs frame.cljs gradients.cljs group.cljs image.cljs mask.cljs path.cljs rect.cljs shape.cljs svg_defs.cljs svg_raw.cljs text.cljs ▾ util/ parser.cljs
To export a penpot file, basically we use the same system that is used to
display shapes in the workspace or viewer. In
shapes/*.cljs there are
components that render one shape of each type into a SVG node.
But to be able to import the file later, some attributes that not match
directly to SVG properties need to be added as metadata (for example,
proportion locks, constraints, stroke alignment...). This is done in the
Finally, to import a file, we make use of
parser.cljs, a module that
parse-data function. It receives a SVG node (possibly with
children) and converts it into a Penpot shape object. There are auxiliary
functions to read and convert each group of attributes, from the node
properties or the metadata (with the
Any attribute that is not included in the export and import functions will not be exported and will be lost if reimporting the file again.
Code handoff #
▾ frontend/ ▾ src/ ▾ app/ ▾ main/ ▾ ui/ ▾ viewer/ ▾ handoff/ ▾ attributes/ blur.cljs common.cljs fill.cljs image.cljs layout.cljs shadow.cljs stroke.cljs svg.cljs text.cljs attributes.cljs code.cljs ▾ util/ code_gen.cljs
In the code handoff view we have two modes:
For the Info tab, the
attributes.cljs module and all modules under
attributes/*.cljs have the components that extracts the attributes to hand
off of each type of shape.
For the Code tab, the
code.cljs module is in charge. For markup code
(currently only SVG mode) it simply takes the SVG nodes from the viewer main
viewport and prettily formats it.
For the style code (currently only CSS), the
code_gen.cljs module has the
functions that convert the shape to CSS atributes.