|
|
|
|---|---|---|
| Quick Overview | User's Guide | Configuration |
To use the full potential of Sketch, it is important to know some fundamental concepts, such as the various kinds of objects that make up a drawing and their relationship. This section introduces these concepts and the terminology needed to talk about them. This terminology is also used in the menus, the status bar and other parts of Sketch's user interface.
Sketch has two fundamentally different kinds of objects: primitives and compound objects.
Primitives are the basic building blocks of a drawing. They are the ones that actually leave marks on the paper. Among this kind of object are the rectangle, the bézier curve (which also serves as a polygon or even as a straight line) and text object.
Most primitives can have fill properties and line properties. Properties are discussed in more detail below.
Compound objects group several primitives or other compound objects together into one object. As such, compound objects are invisible, but the primitives contained in them are not. Therefore, compound objects are mainly interesting for editing purposes.
It is often convenient to group the primitives that form a distinctive
part of a drawing together into a group. For instance, in the sample file
flags.sk each of the flags is a group of several primitives (often
just a few rectangles as many of the flags consist of some stripes).
Whenever you click on one of the flags the whole group is selected not
just the rectangle you clicked on. Thus, most of the time the group is
manipulated as a whole (there are ways to work on the parts of a group
without ungrouping them first, but that is an advanced topic).
There are some compound objects that behave in a special way. The only example at the moment is the BlendGroup. This group consists of two (or more) control objects and a number of objects that are linear interpolations of the control objects. When you edit one of the control objects all interpolated objects are updated automatically.
A drawing consists of primitives organized in compound objects. The entire drawing itself, the document, is a compound object that contains all the others.
When speaking about the objects contained in a compound object, it's convenient to use the terms parent and child. The compound object is the parent of the object it contains, the contained objects are the compound object's children.
The objects are always drawn in the same order with the objects drawn later obscuring the ones drawn earlier in case of overlap. One might also say that some objects lie on top of each other and that objects are drawn from bottom to top. This is the model we usually use and the reason for menu items such as "Move To Top".
The order in which the objects are drawn changes only when the user e