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{
fpGUI - Free Pascal GUI Library
Style Manager as a Singleton
Copyright (C) 2006 - 2007 See the file AUTHORS.txt, included in this
distribution, for details of the copyright.
See the file COPYING.modifiedLGPL, included in this distribution,
for details about redistributing fpGUI.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
}
unit StyleManager;
{$mode objfpc}{$H+}
interface
uses
Classes
,Contnrs
,fpGUI
;
const
cDefaultStyle = 'auto';
type
// A class reference for the TStyle descendants
TStyleClass = class of TStyleAbs;
// A class to hold the TStyle class mappings. The factory maintains
// a list of these and uses the StyleClass property to create the objects.
TStyleClassMapping = class(TObject)
private
FsMappingName: string;
FStyleClass: TStyleClass;
public
constructor Create(const AMappingName: string; AStyleClass: TStyleClass); overload;
property MappingName: string read FsMappingName;
property StyleClass: TStyleClass read FStyleClass;
end;
// Style manager and factory class
{ TStyleManager }
TStyleManager = class(TObject)
private
FList : TObjectList;
FDefaultStyle: TStyleAbs;
FUserStyle: TStyleAbs;
FDefaultStyleType: string;
function GetDefaultStyle: TStyleAbs;
public
constructor Create;
destructor Destroy; override;
property DefaultStyle: TStyleAbs read GetDefaultStyle;
procedure SetStyle(const AStyleName: string);
procedure RegisterClass(const AStyleName: string; AStyleClass : TStyleClass);
function CreateInstance(const AStyleName: string): TStyleAbs; overload;
function CreateInstance: TStyleAbs; overload;
procedure AssignStyleTypes(AStrings: TStrings);
end;
// Singleton
function gStyleManager: TStyleManager;
implementation
uses
SysUtils
,fpGFX
,WindowsStyle
,OpenSoftStyle
,MotifStyle
;
var
uStyleManager: TStyleManager;
{ Creation is deferred to the first request }
function gStyleManager: TStyleManager;
begin
if uStyleManager = nil then
uStyleManager := TStyleManager.Create;
result := uStyleManager;
end;
{ TStyleManager }
function TStyleManager.GetDefaultStyle: TStyleAbs;
begin
if not Assigned(FDefaultStyle) then
// FDefaultStyle.Free;
FDefaultStyle := CreateInstance(FDefaultStyleType);
Result := FDefaultStyle;
end;
constructor TStyleManager.Create;
begin
inherited Create;
FList := TObjectList.Create;
FUserStyle := nil;
FDefaultStyle := nil;
FDefaultStyleType := cDefaultStyle; // will change later
end;
destructor TStyleManager.Destroy;
begin
FDefaultStyle.Free;
FList.Free;
inherited Destroy;
end;
procedure TStyleManager.SetStyle(const AStyleName: string);
var
i: integer;
begin
for i := 0 to FList.Count - 1 do
if UpperCase(TStyleClassMapping(FList.Items[i]).MappingName) =
UpperCase(AStyleName) then
begin
FDefaultStyleType := AStyleName;
Break; //==>
end;
Assert(FDefaultStyleType <> AStyleName,
Format('<%s> does not identify a registered style class.',
[AStyleName]));
end;
// Register a TStyle class for creation by the factory
procedure TStyleManager.RegisterClass(const AStyleName: string;
AStyleClass: TStyleClass);
var
i: integer;
begin
for i := 0 to FList.Count - 1 do
if UpperCase(TStyleClassMapping(FList.Items[i]).MappingName) =
UpperCase(AStyleName) then
Assert(false,
Format('Style class <%s> already registered.',
[AStyleName]));
FList.Add(TStyleClassMapping.Create(AStyleName, AStyleClass));
// writeln('Registering style: ' + AStyleName);
// we will use this later
// FDefaultStyleType := UpperCase(AStyleName);
end;
// Call the factory to create an instance of TStyle
function TStyleManager.CreateInstance(const AStyleName: string): TStyleAbs;
var
i: integer;
begin
result := nil;
for i := 0 to FList.Count - 1 do
if UpperCase(TStyleClassMapping(FList.Items[i]).MappingName) =
UpperCase(AStyleName) then
begin
result := TStyleClassMapping(FList.Items[i]).StyleClass.Create;
Break; //==>
end;
Assert(result <> nil,
Format('<%s> does not identify a registered style class.',
[AStyleName]));
end;
function TStyleManager.CreateInstance: TStyleAbs;
begin
result := CreateInstance(FDefaultStyleType);
end;
// Assing the registered list of TStyle names to a StringList
// This can be used to populate a combobox with the available TStyle
// class types.
procedure TStyleManager.AssignStyleTypes(AStrings: TStrings);
var
i: integer;
begin
AStrings.Clear;
for i := 0 to FList.Count - 1 do
AStrings.Add(TStyleClassMapping(FList.Items[i]).MappingName);
end;
{ TStyleClassMapping }
constructor TStyleClassMapping.Create(const AMappingName: string;
AStyleClass: TStyleClass);
begin
inherited Create;
FsMappingName := AMappingName;
FStyleClass := AStyleClass;
end;
initialization
gStyleManager.RegisterClass(cDefaultStyle, TWin2000Style);
gStyleManager.RegisterClass('Windows 9x', TWin9xStyle);
gStyleManager.RegisterClass('Windows 2000', TWin2000Style);
gStyleManager.RegisterClass('OpenSoft', TOpenSoftStyle);
gStyleManager.RegisterClass('Motif', TMotifStyle);
finalization
uStyleManager.Free;
end.
|
