4 DUIM-DCs Library
4.2 The class hierarchy for DUIM-DCs
A number of base classes are exposed in the DUIM-DCs library, each of which is a subclass of <object>. They are shown in Table 4.1.
<object> | ||
<pen> | ||
<brush> | ||
<palette> | ||
<ink> | See Section 4.2.1 | |
<text-style> | ||
<device-font> |
<pen>This is protocol class for pens. A pen is used to draw 1 dimensional graphics such as lines or outline, using a specific color or pattern.
<brush>The protocol class for brushes. Brushes are used to fill in 2 dimensional areas with a specific color or pattern.
<palette>The protocol class for palettes. A palette provides a set of colors which can be made available to an application.
<ink>This class can be thought of as anything that can be drawn. As the name implies, an ink describes the color and opacity features used by a given pen or brush. That is, the pen and brush define the drawing style (outlining or filling, respectively), and an ink is used to describe the color or pattern that is drawn. This class has a number of subclasses, described in Section 4.2.1.
<text-style>The protocol class for text styles. A text style is a portable way of describing the appearance of a piece of text on screen (its font family, size, weight, and so on) in an abstract fashion. Because the fonts available on a particular computer may not necessarily match the fonts available on the computer of the programmer, DUIM provides a portable model which allows the most suitable font on the user's machine to be chosen at run-time.
<device-font>The protocol class for device-specific fonts, that is, fonts that are resident on a particular device. This is a direct subclass of
<text-style>.