4. Cool bars (vcl only)

A cool bar contains child controls that can be moved and resized independ­ently. Each control resides on an individual band. The user positions the controls by dragging the sizing grip to the left of each band.

4. Combo boxes

A combo box (TComboBox) combines an edit box with a scrollable list. When users enter data into the control by typing or selecting from the list the value of the Text property changes. If AutoComplete is enabled, the application looks for and dis­plays the closest match in the list as the user types the data.

Three types of combo boxes are: standard, drop-down (the default), and drop­down list.

10. Tree views

A tree view (TTreeView) displays items in an indented outline. The control provides buttons that allow nodes to be expanded and collapsed; You can include icons with items' text labels and display different icons to indicate whether a node is expanded or collapsed. You can also include graphics, such as check boxes, that re­flect state information about the items.

10. Date-time pickers and month calendars

In GLX applications, the DateTimePicker component displays a list box for en­tering dates or times, while the MonthCalendar component presents a calendar for en­tering dates or ranges of dates.

10. Scroll boxes

Scroll boxes (TScrollBox) create scrolling areas within a form. Applications often need to display more information than will fit in a particular area. Some con­trols such as list boxes, memos, and forms themselves can automatically scroll their contents.

Another use of scroll boxes is to create multiple scrolling areas (views) in a window. Views are common in commercial word-processor, spreadsheet, and project management applications. Scroll boxes give you the additional flexibility to define arbitrary scrolling subregions of a form.

10. Tab controls

The tab control component (TTabControl) creates a set of tabs that look like notebook dividers. You can create tabs by editing the Tabs property in the Object In­spector; each string in Tabs represents a. tab. The tab control is a single panel with one set of components on it. To change the appearance of the control when the tabs are clicked, you need to write an OnChange event handler. To create a multipage dia­log box, use a page control instead.

10. Page controls

The page control component (TPageControl) is a page set suitable for multi- page dialog boxes. A page control displays multiple overlapping pages that are TTabSheet objects. A page is selected in the user interface by clicking a tab on top of the control.

10. Display controls

There are many ways to provide users with information about the state of an application. For example, some components including Tform have a Caption property that can be set at runtime. You can also create dialog boxes to display messages. In addition, the following components are especially useful for providing visual feed­back at runtime to identify the object.

10. Status bars

Although you can use a panel to make a status bar, it is simpler to use the TStatusBar component. By default, the status bar's Align property is set to alBottom, which takes care of both position and size.

10. Progress bars

When your application performs a time-consuming operation, you can use a progress bar (TProgressBar) to show how much of the task is completed. A progress bar displays a dotted line that grows from left to right.

18. Help and hint properties

Most visual controls can display context-sensitive Help as well L^ _((v L hints at runtime. The HelpContext and HelpFile properties establish a Help ^<s^n|a*|j|ii^,11'^)er and Help file for the control.

The Hint property contains the text string that appears when the mouse pointer over a control or menu item. To enable hints, set Sho^j |_IM| j₍₎ fate; setting ParentShowHint to True causes the control's ShowHint prope^ same value as its parent's.

18. Images

The image component (TImage) displays a graphical image, , -\jtinap, icon, or metafile.

18. Shapes

The shape component displays a geometric shape. It is a nonwit^Q^^Bjltrol (a widget-based control in CLX applications) and therefore, cannot i^_f(,₍,j_{V|) ||(i}erin­put.

18. Bevels

The bevel component (TBevel) is a line that can appear rais^j il^ered. Some components, such as TPanel, have built-in properties to create i_|()rdcrs.

When such properties are unavailable, use TBevel to create beveled %»|j_n |)0^xes> or frames.

18. Paint boxes

The paint box (TPaintBox) allows your application to draw on a j- y^|i'^can OnPaint event handler to render an image directly on the paint box's | №^w"

ing outside the boundaries of the paint box is prevented.

18. Animation control

The animation component is a window that silently displays flw a_u,i,.. \|0deo interleaved (AVI) clip (VCL applications) or a GIF clip (CLX applicJiij^^. ** AVI clip is a series of bitmap frames, like a movie. Although AVI clips c_l( u '.^■nd, animation controls work only with silent AVI clips. The files you use _m ^Hher uncompressed AVI files or AVI clips compressed using run-length enjc^jjfl j^H)-

Tasks

/. Answer the questions:

1. What components do provide additional ways of capturing /«/, .

2. For what are track bars useful? In what way?

3. What does a spin edit control (TSpinEdit) let?

4. How can you divide a form into several panes?

5. What are check boxes?

6. What advantages has TToolBar component?

7. When does the value of the Text property change?

8. What allows nodes to be expanded and collapsed?

9. What usages of scroll bars do you know?

j) What can you create with the help of Tab controls?

k) What is the page control component?

I) What are the ways to provide users with information abouj ^g ^j^^ian application?

m) What does progress bar display? n) What must you do to enable hints? o) What is the bevel component? p) What is the animation component?

2.Translate into English: фиксация ввода; области дорожки; средство редактирования вращения; раскрывающийся список; установление размеров захвата; выровненная схема; устройство выбора даты; определять произвольные области прокрутки формы; свойства подсказки; подсказки непосредственной передачи; скошенные формы и компоненты; средства управления просмотра текста; форма цифрового просмотра; непрерывный диапазон; внутри области; интервалы между импульсами сигнала; кнопка вращения; фиксированные приращения; на каждой области окна; упорядо­чивать и управлять визуальными средствами управления; поддерживать однородные измерения и интервал; показать опции типа всплывающих границ; средство управления постоянно находится на индивидуальной полосе; перемещая захват установления размеров; совмещать окно редактирования с прокручиваемым списком; расширить узлы; сокращать узлы; компонент контроля позиции табуляции; многостраничное диалоговое окно; наклады­вающиеся страницы; обработчик события; для обеспечения визуальной об­ратной связи во время выполнения; идентифицировать объект; следить за позициями и размером; операция, занимающая много времени; отображать пунктир; активизировать подсказки; точечные рисунки и иконки; средство управления вне области окна; рисунок вне границ; серия составляюгцих структур точечных рисунков; использование кодирования с переменной длиной строки.