UIComponent

  + Object
    + Display
      + UIComponent

The UIComponent class implements the behaviours common to all objects making up the user interface. This class is not instantiable, derivable, nor cloneable. The features it offers are only accessible through its predefined derived classes.

The Left and Top properties return the coordinates of the top left corner of a component whilst the Width and Height properties return its size. These properties are read-only. To move an element, you should use the Move method. The coordinates are expressed in standard coordinates with respect to the top left corner of the form containing the component or the top left corner of the screen if the component is a form.

When the component has a border, like a modal form or a button, it is drawn outside the component. The diagram below shows on a PushButton control the values returned by the Left, Top, Width and Height properties :

The ComponentToScreen and ScreenToComponent allow conversion of coordinates relative to components into coordinates relative to the screen, and vice versa. The combination of these two functions is often used to convert coordinates relative to one component into coordinates relative to another component.

The PenDown, PenMove and PenUp events are raised respectively when the user presses down, moves, or releases the stylus on the component. The coordinates are expressed in standard coordinates with respect to the top left corner of the element. The component onto which the user places the stylus captures the events until the stylus is lifted. Thus the PenMove and PenUp events continue to be raised even if it moves outside the area of the component.

Members	Description

ComponentToScreen	Converts coordinates relative to a component into coordinates relative to the screen.
FiveWayNavigator	Event raised when the user presses one of the 5-way navigator keys.
Height	Element height.
Left	Distance between the left edge of the form and the left edge of the element.
Move	Moves or resizes an element.
PenDown	Event raised when the user touches an UI element with the stylus.
PenMove	Event raised when the user moves the stylus.
PenUp	Event raised when the user releases the stylus.
ScreenToComponent	Converts coordinates relative to the screen into coordinates relative a component.
Top	Distance between the top edge of the form and the top edge of the element.
UIRef	Internal reference to a control.
Width	Element width.

Inherited from Display	Description

Arc	Draws an arc.
BackColor	Background color.
BatchLimit	Size of the graphics instruction buffer.
CoordinateSystem	Coordinates system.
CopyArea	Efficiently copies part of a Display object to another.
DrawFont	Font used to draw the text.
Flush	Empties the graphics instruction buffer.
FontMetrics	Returns a FontMetrics object describing the physical charateristics of the currently active font.
ForeColor	Foreground color.
GetPixel	Queries the color of a given pixel.
hWin	Returns the window handle.
Line	Draws a line.
Oval	Draws a circle or ellipse.
Pattern	Defines the pattern used to fill drawings.
Polygon	Draws a polygon.
PutPixel	Sets the color of a pixel.
Rectangle	Draw a rectangle.
ResID	Identifier of the resource associated with the object.
ScaleFont	Enable or disable font scaling.
TextColor	Text color.
TextOut	Draw text.

Inherited from Object	Description

ClassID	Returns the type identifier corresponding to the actual class of the object.
Implements	Determines whether the object implements the features of a given class.
Iterate	Event raised to iterate over the elements of a container object.
Recipient	Recipient of events sent by the object.
Serialize	Event raised to serialize the object content into a stream.

System	Minimal version	Remarks

Palm OS	Palm OS 3.0	N/A