<?xml version="1.0" encoding="UTF-8"?>
<!--

Documentation for LCL (Lazarus Component Library) and LazUtils (Lazarus 
Utilities) are published under the Creative Commons Attribution-ShareAlike 4.0 
International public license.

https://creativecommons.org/licenses/by-sa/4.0/legalcode.txt
https://gitlab.com/freepascal.org/lazarus/lazarus/-/blob/main/docs/cc-by-sa-4-0.txt

Copyright (c) 1997-2025, by the Lazarus Development Team.

-->
<fpdoc-descriptions>
<package name="lcl">
<!--
====================================================================
LazRegions
====================================================================
-->
<module name="LazRegions">
<short>
Implements non-native regions with support for managing their Z-order.
</short>
<descr>
<p>
<file>lazregions.pas</file> contains classes, types, and routines used to 
implement clipping regions in <var>TLazCanvas</var>, and regions used in 
custom-drawn LCL controls.
</p>
<p>
Author: Felipe Monteiro de Carvalho
</p>
</descr>

<!-- unresolved external references -->
<element name="Classes"/>
<element name="SysUtils"/>
<element name="fpcanvas"/>
<element name="LCLType"/>

<!-- enumeration type Visibility: default -->
<element name="TLazRegionFillMode">
<short>
Represents region fill modes used for polygons in Lazarus regions.
</short>
<descr>
<p>
Adheres to the nomenclature used in the Windows GDI API.
</p>
</descr>
<seealso>
<link id="TLazRegionPolygon.FillMode"/>
<link id="TLazRegion.AddPolygon"/>
</seealso>
</element>
<element name="TLazRegionFillMode.rfmOddEven">
<short>
Use the alternate fill mode (fills the area between odd-numbered and 
even-numbered polygon sides on each scan line).
</short>
</element>
<element name="TLazRegionFillMode.rfmWinding">
<short>
Use the winding fill mode (fills any region with a non-zero winding value).
</short>
</element>

<element name="TPointArray">
<short>
Defines an array type used for TPoint values.
</short>
<descr>
<p>
<var>TPointArray</var> is an array type used for <var>TPoint</var> instances 
which define the vertices in a polygon. It is used to implement the 
<var>Points</var> member in <var>TLazRegionPolygon</var>, and passed as an 
argument to the <var>AddPolygon</var> method in <var>TLazRegion</var>. 
</p>
<p>
TPointArray is an alias for the TPointArray type defined in the 
<file>LazUtils</file> <file>graphtype.pp</file> unit.
</p>
</descr>
<version>
Modified in LCL version 4.0 to be an alias to the TPointArray type defined in 
the <file>graphtype.pp</file> unit (LazUtils).
</version>
<seealso>
<link id="TLazRegionPolygon.Points"/>
<link id="TLazRegion.AddPolygon"/>
<link id="#lazutils.graphtype.TPointArray">TPointArray</link>
</seealso>
</element>

<!-- class Visibility: default -->
<element name="TLazRegionPart">
<short>Base class used for rectangular areas in a region.</short>
<descr>
<p>
<var>TLazRegionPart</var> defines the base class used to represent a 
rectangular area in a region. <var>TLazRegionPart</var> is used as the 
ancestor for the <var>TLazRegionRect</var> class.
</p>
</descr>
<seealso>
<link id="TLazRegionRect"/>
</seealso>
</element>

<element name="TLazRegionPart.GetBoundingRect">
<short>Gets the rectangle with the Bounds for an area in a region.</short>
<descr>
<p>
<var>GetBoundingRect</var> is a <var>TRect</var> function used to get the 
rectangle with the Bounds for a rectangular area in a region. In 
TLazRegionPart, the return value contains an empty rectangle (with zero 
assigned to its Left, Top, Right, Bottom, Width, and Height members).
</p>
</descr>
<seealso/>
</element>

<!-- function Visibility: public -->
<element name="TLazRegionPart.IsPointInPart">
<short>
Indicates if a point with the specified coordinates is within the bounds for 
the rectangular area.
</short>
<descr>
<p>
Always returns <var>False</var> in <var>TLazRegionPart</var>; it uses an 
empty rectangle as its Bounds (Left, Top, Bottom, and Right set to zero).
</p>
</descr>
<errors></errors>
<seealso/>
</element>
<element name="TLazRegionPart.IsPointInPart.Result">
<short>
<b>True</b> when the coordinates are located in the bounds for the 
rectangular area.
</short>
</element>
<element name="TLazRegionPart.IsPointInPart.AX">
<short>Horizontal coordinate for the point.</short>
</element>
<element name="TLazRegionPart.IsPointInPart.AY">
<short>Vertical coordinate for the point.</short>
</element>

<!-- class Visibility: default -->
<element name="TLazRegionRect">
<short>Implements a region defined by a TRect structure.</short>
<descr>
<p>
<var>TLazRegionRect</var> is a <var>TLazRegionPart</var> descendant which 
implements a region as a rectangular area. It includes a <var>Rect</var> 
member used to store the <var>TRect</var> with the bounds for the region. It 
also provides an overridden <var>IsPointInPart</var> method to examine the 
Rect member when locating a point in the region. Instances of TLazRegionRect 
are created when the <var>AddRectangle</var> method in <var>TLazRegion</var> 
is called.
</p>
</descr>
<seealso>
<link id="TLazRegionPart"/>
<link id="TLazRegion.Parts"/>
<link id="TLazRegion.AddRectangle"/>
</seealso>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegionRect.Rect">
<short>Rectangle with the bounds that defines the region.</short>
<descr>
<p>
<var>Rect</var> is a <var>TRect</var> member which contains the rectangular 
area that is the bounds for the region.
</p>
</descr>
<seealso/>
</element>

<!-- function Visibility: public -->
<element name="TLazRegionRect.IsPointInPart">
<short>
Indicates if a point with the specified coordinates is within the rectangle 
used as the bounds for the region.
</short>
<descr>
<p>
Overrides the method in the ancestor class to use the <var>Rect</var> member 
as the bounds for the region.
</p>
</descr>
<seealso/>
</element>
<element name="TLazRegionRect.IsPointInPart.Result">
<short>
<b>True</b> when the coordinates are located in the bounds rectangle for the 
region.
</short>
</element>
<element name="TLazRegionRect.IsPointInPart.AX">
<short>Horizontal coordinate for the point.</short>
</element>
<element name="TLazRegionRect.IsPointInPart.AY">
<short>Vertical coordinate for the point.</short>
</element>

<!-- class Visibility: default -->
<element name="TLazRegionPolygon">
<short>
Represents a region defined as a series of vertices for a polygon.
</short>
<descr>
<p>
<var>TLazRegionPolygon</var> is a <var>TLazRegionPart</var> descendant which 
implements a region as a polygonal area defined by a series of vertices.
</p>
<p>
The <var>Points</var> member contains the <var>TPoint</var> values that 
define the vertices for the polygon. <var>FillMode</var> defines how the 
interior of the polygon is filled, and uses values like those defined for the 
Windows GDI API. An overridden <var>IsPointInPart</var> is provided to 
determine if a point is within the bounds for the polygonal area.
</p>
<p>
Instances of TLazRegionPolygon are created when the <var>AddPolygon</var> 
method in <var>TLazRegion</var> is called.
</p>
</descr>
<seealso>
<link id="TLazRegion.AddPolygon"/>
<link id="TLazRegion.Parts"/>
<link id="TLazRegionPart"/>
</seealso>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegionPolygon.Points">
<short>
Array of TPoint values that define the vertices for the polygonal region.
</short>
<descr/>
<seealso/>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegionPolygon.FillMode">
<short>Fill mode used for the polygon.</short>
<descr/>
<seealso/>
</element>

<!-- function Visibility: public -->
<element name="TLazRegionPolygon.IsPointInPart">
<short>
Indicates if a point with the specified coordinates is within the vertices 
for the polygonal region.
</short>
<descr>
<p>
<var>IsPointInPart</var> is an overridden <var>Boolean</var> function which 
indicates if a point with the specified coordinates is within the vertices 
for the polygonal region.
</p>
<p>
<var>IsPointInPart</var> calls the <var>IsPointInPolygon</var> routine to get 
the return value for the method. The return value is <b>True</b> when the 
point in <var>AX</var> and <var>AY</var> is located inside the polygon 
vertices defined in the <var>Points</var> member.
</p>
</descr>
<seealso>
<link id="IsPointInPolygon"/>
<link id="TLazRegionPolygon.Points"/>
</seealso>
</element>
<element name="TLazRegionPolygon.IsPointInPart.Result">
<short>
<b>True</b> when the point occurs inside the vertices for the polygonal 
region.
</short>
</element>
<element name="TLazRegionPolygon.IsPointInPart.AX">
<short>Horizontal coordinate for the point.</short>
</element>
<element name="TLazRegionPolygon.IsPointInPart.AY">
<short>Vertical coordinate for the point.</short>
</element>

<element name="TLazRegionEllipse">
<short>Implements a region defined as an Ellipse.</short>
<descr>
<p>
<var>TLazRegionEllipse</var> is a <var>TLazRegionPart</var> descendant which 
implements a region defined as an elliptical area with the specified vertex 
and co-vertex. The <var>X1</var>, <var>X2</var>, <var>Y1</var>, and 
<var>Y2</var> members are provided to represent the horizontal and vertical 
coordinates for the vertex and co-vertex points.
</p>
<p>
Instances of <var>TLazRegionEllipse</var> are created when the 
<var>AddEllipse</var> method in <var>TLazRegion</var> is called.
</p>
</descr>
<seealso>
<link id="TLazRegion.AddEllipse"/>
<link id="TLazRegion.Parts"/>
<link id="TLazRegionPart"/>
</seealso>
</element>

<element name="TLazRegionEllipse.X1">
<short>Horizontal coordinate for the vertex.</short>
<descr/>
<seealso/>
</element>

<element name="TLazRegionEllipse.Y1">
<short>Vertical coordinate for the vertex.</short>
<descr/>
<seealso/>
</element>

<element name="TLazRegionEllipse.X2">
<short>Horizontal coordinate for the co-vertex.</short>
<descr/>
<seealso/>
</element>

<element name="TLazRegionEllipse.Y2">
<short>Vertical coordinate for the co-vertex.</short>
<descr/>
<seealso/>
</element>

<element name="TLazRegionEllipse.IsPointInPart">
<short>
Indicates if the specified point is located inside the elliptical area for 
the region.
</short>
<descr>
<p>
The equation for the inner area of an axis aligned ellipse is:
</p>
<code>(X/a)^2 + (Y/b)^2 &lt;= 1</code>
</descr>
<seealso/>
</element>
<element name="TLazRegionEllipse.IsPointInPart.Result">
<short>
<b>True</b> when the specified point is located inside the area for the 
ellipse.
</short>
</element>
<element name="TLazRegionEllipse.IsPointInPart.AX">
<short>Horizontal coordinate for the point.</short>
</element>
<element name="TLazRegionEllipse.IsPointInPart.AY">
<short>Vertical coordinate for the point.</short>
</element>

<element name="TFPCustomRegion">
<short/>
<descr/>
<seealso/>
<version>
Defined for FPC version 2.6 or older. Defined in <file>fpcanvas.pp</file> in 
the FCL for later FPC versions.
</version>
</element>

<element name="TFPCustomRegion.GetBoundingRect">
<short/>
<descr/>
<seealso/>
<version>
Defined for FPC version 2.6. Defined in <file>fpcanvas.pp</file> for later 
FPC versions.
</version>
</element>
<element name="TFPCustomRegion.GetBoundingRect.Result">
<short/>
<version>
Defined for FPC version 2.6. Defined in <file>fpcanvas.pp</file> for later 
FPC versions.
</version>
</element>

<element name="TFPCustomRegion.IsPointInRegion">
<short/>
<version>
Defined for FPC version 2.6. Defined in <file>fpcanvas.pp</file> for later 
FPC versions.
</version>
</element>
<element name="TFPCustomRegion.IsPointInRegion.Result">
<short/>
<version>
Defined for FPC version 2.6. Defined in <file>fpcanvas.pp</file> for later 
FPC versions.
</version>
</element>
<element name="TFPCustomRegion.IsPointInRegion.AX">
<short/>
<version>
Defined for FPC version 2.6. Defined in <file>fpcanvas.pp</file> for later 
FPC versions.
</version>
</element>
<element name="TFPCustomRegion.IsPointInRegion.AY">
<short/>
<version>
Defined for FPC version 2.6. Defined in <file>fpcanvas.pp</file> for later 
FPC versions.
</version>
</element>

<!-- class Visibility: default -->
<element name="TLazRegion">
<short>Represents a custom region in the Lazarus LCL.</short>
<descr>
<p>
<var>TLazRegion</var> is a <var>TFPCustomRegion</var> descendant which 
represents a region as used in the Lazarus LCL. It is used to implement the 
clipping region in <var>TLazCanvas</var>, and in custom-drawn windowed LCL 
controls. The region is composed of <var>TLazRegionPart</var> descendants 
representing the rectangles, polygons, and ellipses that define the display 
area on a device. TLazRegion provides overridden methods to query information 
for the composite display area.
</p>
<p>
The parts of a region should all be inside valid areas for the region. If a 
combine operation removes an area in the region, then the area should be 
removed from all parts for the region. There is no z-order for the 
<var>Parts</var>, they are all validly inside the region area.
</p>
</descr>
<seealso>
<link id="TLazRegionWithChilds"/>
<link id="#lcl.lazcanvas.TLazCanvas">TLazCanvas</link>
<link id="#lcl.lazcanvas.TLazCanvasState.ClipRegion">TLazCanvasState.ClipRegion</link>
</seealso>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegion.Parts">
<short>
List with the Rectangles, Polygons, and Ellipses that define the display area 
for the region.
</short>
<descr/>
<seealso/>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegion.IsSimpleRectRegion">
<short>
Indicates whether this region is composed of a single rectangular part.
</short>
<descr>
<p>
Use <var>Rect</var> to access the <var>TRect</var> structure with the bounds 
for the rectangular region.
</p>
</descr>
<seealso/>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegion.Rect">
<short>TRect instance with the bounds for the region.</short>
<descr/>
<seealso/>
</element>

<!-- constructor Visibility: public -->
<element name="TLazRegion.Create">
<short>Constructor for the class instance.</short>
<descr>
<p>
<var>Create</var> is the constructor for the class instance. Create calls the 
inherited constructor to initialize the class instance. Create allocates 
resources needed for the <var>Parts</var> member, and sets the default value 
for <var>IsSimpleRectRegion</var> to <b>True</b>.
</p>
</descr>
<seealso/>
</element>

<!-- destructor Visibility: public -->
<element name="TLazRegion.Destroy">
<short>Destructor for the class instance.</short>
<descr>
<p>
<var>Destroy</var> is the overridden destructor for the class instance. 
Destroy ensures that resource allocated for the <var>Parts</var> member are 
freed. Destroy calls the inherited destructor prior to exiting from the 
method.
</p>
<remark>
Destroy does not call <var>Parts.Clear</var> prior to freeing the 
<var>Parts</var> member; that action is performed in the destructor for the 
<var>TFPList</var> class instance.
</remark>
</descr>
<seealso/>
</element>

<element name="TLazRegion.Assign">
<short>Stores values from ASrcRegion in the current class instance.</short>
<descr>
<p>
Calls <var>Clear</var> to remove any items stored in <var>Parts</var>.
Calls <var>AddPartsFromRegion</var> to capture the values from the source 
region.
</p>
</descr>
<seealso/>
</element>
<element name="TLazRegion.Assign.ASrcRegion">
<short>Region with the values stored in the method.</short>
</element>

<element name="TLazRegion.Clear">
<short>
Frees all of the TLazRegionPart instances in Parts, and clears the list.
</short>
<descr>
<p>
Frees all of the <var>TLazRegionPart</var> instances in the <var>Parts</var> 
member, and clears the list.
</p>
</descr>
<seealso/>
</element>

<element name="TLazRegion.CombineWith">
<short>
Combines the specified source region using the given region operation.
</short>
<descr>
<p>
<var>ASrcRegion</var> is the source region with the Parts applied in the 
method.
</p>
<p>
<var>AOperation</var> can contain a Combine Region flag that includes:
</p>
<ul>
<li>RGN_AND (1)</li>
<li>RGN_OR (2)</li>
<li>RGN_XOR (3)</li>
<li>RGN_DIFF (4)</li>
<li>RGN_COPY(5)</li>
</ul>
<remark>
In the current LCL version, only <var>RGN_COPY</var> and <var>RGN_OR</var> 
are implemented; all other values are ignored and no actions are performed in 
the method. RGN_COPY causes the Parts in ASrcRegion to be assigned to the 
Parts in the current class instance. RGN_OR cause the Parts in ASrcRegion to 
the be added to the Parts in the current class instance.
</remark>
</descr>
<seealso/>
</element>
<element name="TLazRegion.CombineWith.ASrcRegion">
<short>Source region with values applied in the method.</short>
</element>
<element name="TLazRegion.CombineWith.AOperation">
<short>
Combine region flag with the operation to perform for the subregions.
</short>
</element>

<element name="TLazRegion.GetRegionKind">
<short>Gets the type of region represented in the class instance.</short>
<descr>
<p>
<var>GetRegionKind</var> is a <var>Longint</var> function used to get the 
type of region represented in the class instance. The return value adheres to 
the region flag values used in the Windows GDI API, and can include one of 
the following:
</p>
<dl>
<dt>COMPLEXREGION (3)</dt>
<dd>
The region has more than one rectangle, polygon, or ellipse. Used when 
IsSimpleRectRegion is <b>False</b>.
</dd>
<dt>SIMPLEREGION (2)</dt>
<dd>
The region is a simple rectangle defined using the Rect member. Used when 
IsSimpleRectRegion is <b>True</b>, and Rect is not an empty rectangle (Left, 
Top, Bottom, and Right all contain zero).
</dd>
<dt>NULLREGION (1)</dt>
<dd>
The region has an empty value in its Rect member (Left, Top, Width, and 
Height all contain zero).
</dd>
<dt>REGION_ERROR (0)</dt>
<dd>An error occurred. Not used in GetRegionKind.</dd>
</dl>
</descr>
<seealso/>
</element>
<element name="TLazRegion.GetRegionKind.Result">
<short>Region flag value for the class instance.</short>
</element>

<element name="TLazRegion.IsSimpleRectEmpty">
<short>
Indicates whether the Rect member contains empty or invalid rectangle 
coordinates.
</short>
<descr/>
<seealso/>
</element>
<element name="TLazRegion.IsSimpleRectEmpty.Result">
<short>
<b>True</b> when the dimensions for the rectangle are invalid.
</short>
</element>

<element name="TLazRegion.AddPart">
<short>Adds the specified part as a subregion in the Parts member.</short>
<descr>
<p>
<var>AddPart</var> is a procedure used to add the specified 
<var>TLazRegionPart</var> in <var>APart</var> to the <var>Parts</var> member 
in the class instance. AddPart calls the <var>TFPList.Add</var> method to 
store the value in APart in the list. AddPart calls 
<var>DoChangeToComplexRegion</var> to update <var>IsSimpleRectRegion</var> to 
reflect the current composition for the region.
</p>
<p>
AddPart is used in the implementation of the <var>AddRectangle</var>, 
<var>AddPolygon</var>, and <var>AddEllipse</var> methods.
</p>
</descr>
<seealso>
<link id="TLazRegion.DoChangeToComplexRegion"/>
<link id="TLazRegion.IsSimpleRectRegion"/>
<link id="TLazRegion.AddRectangle"/>
<link id="TLazRegion.AddPolygon"/>
<link id="TLazRegion.AddEllipse"/>
<link id="TLazRegionPart"/>
</seealso>
</element>
<element name="TLazRegion.AddPart.APart">
<short>TLazRegionPart (or descendant) added in the method.</short>
</element>

<!-- procedure Visibility: public -->
<element name="TLazRegion.AddRectangle">
<short>Adds the specified TRect instance to the Parts member.</short>
<descr>
<p>
<var>AddRectangle</var> is a procedure used to add a rectangular region 
defined by the <var>TRect</var> instance in <var>ARect</var> to the 
<var>Parts</var> member. AddRectangle creates a <var>TLazRegionRect</var> 
instance and assigns ARect to its <var>Rect</var> member. AddRectangle calls 
<var>AddPart</var> to store the TLazRegionRect instance in Parts.
</p>
</descr>
<seealso>
<link id="TLazRegionRect"/>
<link id="TLazRegion.AddPart"/>
<link id="TLazRegion.Parts"/>
</seealso>
</element>
<element name="TLazRegion.AddRectangle.ARect">
<short>TRect instance with the rectangular region added in the method.</short>
</element>

<!-- procedure Visibility: public -->
<element name="TLazRegion.AddPolygon">
<short>
Adds a polygonal area with the specified vertices to the region.
</short>
<descr>
<p>
<var>AddPolygon</var> is a procedure used to add a polygonal area with the 
specified vertices to the region. <var>APoints</var> is an array with 
<var>TPoint</var> instances that define each of the vertices for the polygon. 
<var>AFillMode</var> is a <var>TLazRegionFillMode</var> value that defines 
the fill mode for the polygonal area.
</p>
<p>
AddPolygon creates a <var>TLazRegionPolygon</var> instance that is used to 
store the area definition in the <var>Parts</var> member. The arguments to 
the method are assigned to the <var>Points</var> and <var>FillMode</var> 
members in the new class instance. AddPolygon calls <var>AddPart</var> to 
store the new TLazRegionPolygon instance in Parts.
</p>
</descr>
<seealso>
<link id="TLazRegion.AddPart"/>
<link id="TLazRegionPolygon"/>
<link id="TLazRegionPolygon.Points"/>
<link id="TLazRegionPolygon.FillMode"/>
<link id="TPointArray"/>
<link id="TLazRegionFillMode"/>
<link id="#lazutils.graphtype.TPointArray">GraphType.TPointArray</link>
</seealso>
</element>
<element name="TLazRegion.AddPolygon.APoints">
<short>
Array of TPoint instances representing the vertices for the polygon.
</short>
</element>
<element name="TLazRegion.AddPolygon.AFillMode">
<short>TLazRegionFillMode value used for the polygon.</short>
</element>

<element name="TLazRegion.AddEllipse">
<short>
Adds an elliptical area with the specified co-vertices to the region.
</short>
<descr>
<p>
<var>AddEllipse</var> is a procedure used to add an elliptical area with the 
specified co-vertices to the region. <var>AX1</var> and <var>AY1</var> is the 
point where the endpoint for the long axis is located. <var>AX2</var> and 
<var>AY2</var> is the point where the endpoint for the short axis is located. 
Each point is located perpendicular to the opposing axis, and its diameter 
bisects the opposing axis.
</p>
<p>
AddEllipse creates an instance of <var>TLazRegionEllipse</var> and assigns 
the arguments to the corresponding members in the new class instance. 
AddEllipse calls the <var>AddPart</var> method to store the new 
TLazRegionEllipse instance in the <var>Parts</var> member.
</p>
</descr>
<seealso>
<link id="TLazRegion.Parts"/>
<link id="TLazRegion.AddPart"/>
<link id="TLazRegionEllipse"/>
</seealso>
</element>
<element name="TLazRegion.AddEllipse.AX1">
<short>Horizontal coordinate for the endpoint of the major axis.</short>
</element>
<element name="TLazRegion.AddEllipse.AY1">
<short>Vertical coordinate for the endpoint of the major axis.</short>
</element>
<element name="TLazRegion.AddEllipse.AX2">
<short>Horizontal coordinate for the endpoint of the minor axis.</short>
</element>
<element name="TLazRegion.AddEllipse.AY2">
<short>Vertical coordinate for the endpoint of the minor axis.</short>
</element>

<!-- procedure Visibility: public -->
<element name="TLazRegion.SetAsSimpleRectRegion">
<short>Sets the area for the region to the specified rectangle.</short>
<descr/>
<errors></errors>
<seealso/>
</element>
<element name="TLazRegion.SetAsSimpleRectRegion.ARect">
<short>TRect with the bounds for the region.</short>
</element>

<element name="TLazRegion.AddPartsFromRegion">
<short>
Adds the region (and any subregions) from ASrcRegion to the current class 
instance.
</short>
<descr>
<p>
<var>AddPartsFromRegion</var> is a procedure used to add the region in 
<var>ASrcRegion</var> to the current class instance. ASrcRegion can be 
represented as a simple rectangular region, or a complex region using 
rectangles, polygons, and/or ellipses.
</p>
<p>
AddPartsFromRegion ensures that the <var>Rect</var> or <var>Parts</var> 
members from ASrcRegion are combined in the correct manner with the values in 
Rect or Parts for the current class instance. The value in 
<var>IsSimpleRectRegion</var> is set to <b>False</b> if it was necessary to 
add entries to the <var>Parts</var> member in the method.
</p>
</descr>
<seealso>
<link id="TLazRegion.Rect"/>
<link id="TLazRegion.IsSimpleRectRegion"/>
<link id="TLazRegion.Parts"/>
<link id="TLazRegion.AddPart"/>
</seealso>
</element>
<element name="TLazRegion.AddPartsFromRegion.ASrcRegion">
<short>Region with the values added in the method.</short>
</element>

<element name="TLazRegion.DoChangeToComplexRegion">
<short>
Adds the value in Rect to the Parts member, and resets the value in 
IsSimpleRectRegion.
</short>
<descr>
<p>
<var>DoChangeToComplexRegion</var> is a procedure used to change the region 
from a simple rectangle to a complex region as defined in the 
<var>Parts</var> member. DoChangeToComplexRegion uses the values from 
<var>IsSimpleRectRegion</var> and <var>IsSimpleRectEmpty</var> to determine 
if any actions are required in the method. No actions are performed when 
IsSimpleRectRegion is <b>False</b>, or when IsSimpleRectEmpty returns 
<b>True</b>.
</p>
<p>
DoChangeToComplexRegion changes the value in IsSimpleRectRegion to 
<b>False</b>, and calls <var>AddRectangle</var> to store the value in 
<var>Rect</var> in the <var>Parts</var> member.
</p>
</descr>
<seealso/>
</element>

<!-- function Visibility: public -->
<element name="TLazRegion.GetBoundingRect">
<short>Gets the bounds for the region as a rectangle.</short>
<descr>
<p>
<var>GetBoundingRect</var> is a <var>TRect</var> function used to get the 
rectangle structure with the bounds for the region. GetBoundingRect uses the 
value in the <var>Rect</var> member as the return value for the method.
</p>
</descr>
<seealso/>
</element>
<element name="TLazRegion.GetBoundingRect.Result">
<short>TRect with the bounds for the region.</short>
</element>

<!-- function Visibility: public -->
<element name="TLazRegion.IsPointInRegion">
<short>Checks whether the specified point is inside the region.</short>
<descr>
<p>
Checks if the specified point is inside the display area for the region. Uses 
the value in <var>IsSimpleRectRegion</var> to determine whether 
<var>Rect</var> contains the bounds for the region. When it contains 
<b>False</b>, the values in the <var>Parts</var> member are used to determine 
the return value.
</p>
<p>
Returns <b>True</b> when the specified point is located inside the rectangle 
or one of the subregions.
</p>
</descr>
<seealso/>
</element>
<element name="TLazRegion.IsPointInRegion.Result">
<short>
<b>True</b> when the point is located inside the rectangle or one of the 
subregions that define the bounds for the region.
</short>
</element>
<element name="TLazRegion.IsPointInRegion.AX">
<short>Horizontal coordinate for the point.</short>
</element>
<element name="TLazRegion.IsPointInRegion.AY">
<short>Vertical coordinate for the point.</short>
</element>

<!-- class Visibility: default -->
<element name="TLazRegionWithChilds">
<short>Implement a region which can have other regions as children.</short>
<descr>
<p>
<var>TLazRegionWithChilds</var> is a <var>TLazRegion</var> descendant which 
implements a region which can hold a list of other region holders. Use 
<var>Parent</var> to access the complex region which owns the current class 
instance. Use <var>Childs</var> to access the list of subregions for the 
class instance.
</p>
</descr>
<seealso/>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegionWithChilds.Parent">
<short>
Complex region which hosts the subregions in the current class instance.
</short>
<descr>
<remark>
<var>Parent</var> is not maintain in methods for the class instance; it is 
available for use in widget set classes which utilize the region.
</remark>
</descr>
<seealso/>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegionWithChilds.Childs">
<short>List of subregions for the current class instance.</short>
<descr>
<p>
The order in this list is also the Z-Order of the sub regions inside it. The 
element with index zero is the bottom-most one.
</p>
</descr>
<seealso/>
</element>

<!-- variable Visibility: public -->
<element name="TLazRegionWithChilds.UserData">
<short>Contains an available link to another object.</short>
<descr>
Contains an available link to another object.
</descr>
<seealso/>
</element>

<!-- constructor Visibility: public -->
<element name="TLazRegionWithChilds.Create">
<short>Constructor for the class instance.</short>
<descr>
<p>
<var>Create</var> is the overridden constructor for the class instance. 
Create calls the inherited constructor to initialize the class instance, and 
allocates resources needed for the <var>Childs</var> member.
</p>
</descr>
<seealso/>
</element>

<!-- destructor Visibility: public -->
<element name="TLazRegionWithChilds.Destroy">
<short>Destructor for the class instance.</short>
<descr>
<p>
<var>Destroy</var> is the overridden destructor for the class instance. 
Destroy ensures that resources allocated to the <var>Childs</var> member are 
freed. Destroy calls the inherited destructor prior to exiting from the 
method.
</p>
</descr>
<seealso/>
</element>

<!-- function Visibility: public -->
<element name="TLazRegionWithChilds.IsPointInRegion">
<short>
Indicates if the specified point is within the bounds for the region.
</short>
<descr>
<p>
Returns itself or a child, depending on where the point was found, or nil if 
the point is neither in the region nor in any children.
</p>
<p>
Part of the behavior is implemented in TLazRegionWithChilds.
</p>
</descr>
<seealso/>
</element>
<element name="TLazRegionWithChilds.IsPointInRegion.Result">
<short>
<b>True</b> when the point is within the bounds for one of the child areas in 
the region.
</short>
</element>
<element name="TLazRegionWithChilds.IsPointInRegion.AX">
<short>Horizontal coordinate for the point.</short>
</element>
<element name="TLazRegionWithChilds.IsPointInRegion.AY">
<short>Vertical coordinate for the point.</short>
</element>

<!-- function Visibility: default -->
<element name="IsPointInPolygon">
<short>
Determines if the specified point is inside the vertices for the specified 
polygon.
</short>
<descr>
<p>
The function will return <b>True</b> if the point at AX, AY is inside the 
specified polygon. Returns <b>False</b> if it is not.
</p>
<p>
Original C code:
<url href="http://www.visibone.com/inpoly/inpoly.c.txt">
http://www.visibone.com/inpoly/inpoly.c.txt
</url>.
</p>
<p>
Translated from C to Pascal by: Felipe Monteiro de Carvalho.
</p>
</descr>
<seealso>
<link id="TLazRegionPolygon.IsPointInPart"/>
</seealso>
</element>
<element name="IsPointInPolygon.Result">
<short>
<b>True</b> when the specified point is located within the polygon using the 
specified vertices.
</short>
</element>
<element name="IsPointInPolygon.AX">
<short>Horizontal coordinate for the point.</short>
</element>
<element name="IsPointInPolygon.AY">
<short>Vertical coordinate for the point.</short>
</element>
<element name="IsPointInPolygon.APolygon">
<short>
Array with the TPoint values that define the vertices for the polygon.
</short>
</element>

</module>
<!-- LazRegions -->
</package>
</fpdoc-descriptions>
