Inside
Macintosh, Volume I, page I-10
“The
routines available for use in Macintosh programs are divided according to
function, into what are in most cases called “managers” of the feature they
support. … Most are part of either the Operating System or the User Interface
Toolbox and are in the Macintosh ROM.
“The
Operating System is at the lowest level; it does basic tasks such as
input and putput, memory management, and interrupt handling. The User
Interface Toolbox is a level above the Operating System; it helps you
implement the standard Macintosh user interface in your application. The
Toolbox calls the Operating System to do low-level operations. …
“RAM-based
software is available as well. In most cases this software performs specialized
operations (such as floating-point arithmetic) that aren’t integral to the user
interface but may be useful to some applications.” —Inside Macintosh,
Volume I, page I-9
“The
Macintosh User Interface Toolbox provides a simple means of constructing
application programs that conform to the standard Macintosh user interface. By
offering a common set of routines that every application calls to implement the
user interface, the Toolbox not only ensures familiarity and consistency for
the user but also helps reduce the application’s code size and development
time. At the same time, it allows a great deal of flexibility: An application
can use its own code instead of a Toolbox call wherever appropriate, and can
define its own types of windows, menus, controls, and desk accessories.
“Figure 2 [below] shows the various parts of the Toolbox in rough order of their relative level. There are many interconnections between these parts; the higher ones often call those at the lower levels.” —Inside Macintosh, Volume I, page I-9
“To
keep the data of an application separate from its code, making the data easier
to modify and easier to share among applications, the [Macintosh User
Interface] Toolbox includes the Resource Manager. The Resource Manager
lets you, for example, store menus separetly from your code so that they can be
edited or translated without requiring recompilation of the code. It also
allows you to get standard data, such as the I-beam pointer for inserting text,
from a shared system file. When you call other parts of the Toolbox that need
access to the data, they call the Resource Manager. Although most applications
never need to call the Resource Manager directly, an understanding of the
concepts behind it is essential because they’re basic to so many other
operations.” —Inside Macintosh, Volume I, page I-9
“Graphics
are an important part of every Macintosh application. All graphic operations on
the Macintosh are performed by QuickDraw. To draw something on the
screen, you’ll often call one of the other parts of the [Macintosh User
Interface] Toolbox, but it will in turn call QuickDraw. You’ll also call
QuickDraw directly, usually to draw inside a window, or just to set up
constructs like rectangles that you’ll need when making other Toolbox calls.
QuickDraw’s underlying concepts, like those of the Resource Manager, are
important for you to understand.” —Inside Macintosh, Volume I, page I-11