KOL: what changed

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1	1		## Introduction
2	2
3	3		![](/wiki-images/a/a5/Kolmck.png)\
4		-	\
	4	+
5	5		The Key Objects Library, a.k.a. KOL, is an object oriented framework created by Vladimir Kladov ([website](http://f0460945.xsph.ru/rindex.htm)) in 2000. It is the successor to the XCL library by the same author. The Mirror Classes Kit, a.k.a. MCK, is a set of visual components to write KOL applications in a visual design way, from within the Delphi IDE.
6	6
7	7		The current point release is 3.23 for KOL and 3.23 for MCK.
8	8
9	9		New versions appear with Irregular intervals, but the library is currently maintained. There is an svn repository for KOL and MCK at <https://svn.code.sf.net/p/kolmck/code/> which is usually more up to date than the point releases.
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11	11		The main reason creating this library is explained through the dissatisfaction of Vladimir and others towards ever increasing code bloat. Nobody seemed to care anymore about efficient coding. According to KOL users there a strong correlation between Moore's law and degrading code optimizing efficiency.
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13	13		An MCK project designed in a Delphi IDE can be recompiled with both 32 bit and 64 bit FPC 2.7.1 or later compilers without change. This way you can without having to upgrade your Delphi to a recent version:
14	14
15	15		- obtain a 64 bit version of a project.
16	16		- obtain a unicode version of a Delphi project (5-2007) by simply defining -dUNICODE_CTRLS.
17	17		- or both!
18	18
19	19		The framework centers around three basic concepts:
20	20
21	21		- It uses - some say old school - pascal objects, not classes.
22	22		- Most of the widgets are basically one and the same object. Polymorphism is through constructing functions.
23	23		- It ignores the VCL/LCL, in fact it attempts to replace them.
24	24
25	25		This has several advantages, some of which are:
26	26
27	27		- The size of your binary is very tiny, on average more than 20 times smaller than a VCL/LCL binary, but a factor 100 or more is not unusual.
28	28		- KOL binaries (both executables and dll's) have much much faster load times and feel snappier.
29	29		- KOL is very easy to extend once you understand its concepts. It is a fully object oriented framework.
30	30
31	31		It also has very obvious disadvantages, some of which are:
32	32
33	33		- KOL is a framework. It doesn't mix very well with classes and it can't be sensibly mixed with LCL/VCL code because you will loose the size advantage.
34	34		- If you are not familiar with the old Object Pascal paradigm from Turbo Pascal the learning curve can be steep.
35	35		- You will miss some functionality that has become common place, like RTTI, but most of these features are often codebloat and the reason why KOL exists in the first place.
36	36		- Because you are often working on the same object with multiple appearances, it may be confusing that some methods or properties that you can see in the code editor do not apply.
37	37
38	38		## Requirements
39	39
40	40		- Free Pascal compiler 2.6.4 or later for Win32
41	41		- Free Pascal compiler 2.7.1 or later for Win64
42	42		- [KOL 3.23 or later](http://f0460945.xsph.ru/rindex.htm) for win32
43	43		- The Mirror Classes Kit a.k.a. MCK for those who want to develop using a visual designer like Lazarus or Delphi.
44	44		- [Release preview of KOL 3.23-64](https://yadi.sk/d/Z0uMP31_67nJY) for KOL win32/64
45	45		- [[KOL-CE\|See the KOL CE page]] for win-ce development and requirements.
46	46		- Not required, but recommended is a copy of FPC's RTL and/or Delphi's RTL sources
47	47
48	48		## Supported targets
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50	50		- All 32-bit Windows: from Windows 95 to Windows 8.1.
51	51		- All 64-bit x86_64 from Windows 2000 to Windows 8.1.
52	52		- [[WinCE port\|Windows CE]] based PocketPC and Smartphones. More information on the [[KOL-CE\|KOL CE page]]
53	53
54	54		## Example
55	55
56	56		Let's illustrate KOL with a simple example. A form, a button and some action. You will notice that the code resembles that of a LCL/VCL application and basically: It does exactly the same! The main difference is the use of objects and pointer to objects instead of classes and the use of constructing functions instead of constructors.
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58	58		Here's the main program file:
59	59
60	60		``` pascal
61	61		program koldemo;
62	62		{This line makes us FPC and Delphi compatible}
63	63		{$IFDEF FPC}{$MODE DELPHI}{$H+}{$ENDIF}
64	64		{$APPTYPE GUI}
65	65		uses
66	66		Kol,
67	67		koldemo1 in 'koldemo1.pas';
68	68
69	69		begin
70	70		NewForm1( Form1, nil);
71	71		Run(Form1.form);
72	72		end.
73	73		```
74	74
75		-	\
76	75		And here is the main unit, again, you will notice it is very similar to LCL/VCL code:\
77	76
78	77		``` pascal
79	78		unit koldemo1;
80	79
81	80		interface
82	81		uses
83	82		Windows, Messages, Kol;
84	83		const
85	84		cps:KolString = 'Kol project in ' + {$IFDEF FPC}'Freepascal '{$ELSE}'Delphi '{$ENDIF} +
86	85		{$IFDEF WIN64}'64 bits '{$ELSE}'32 bits '{$ENDIF} +
87	86		{$IFDEF UNICODE_CTRLS}'Unicode'{$ELSE}'Ansi'{$ENDIF};
88	87		type
89	88
90	89		PForm1=^TForm1;
91	90		TForm1=object(Tobj)
92	91		{Note both widgets are of the same type}
93	92		Form, Button:pControl;
94	93		public
95	94		{The message handler for our Button}
96	95		procedure ButtonClick(Sender:PObj);
97	96		end;
98	97
99	98		procedure NewForm1( var Result: PForm1; AParent: PControl );
100	99
101	100		var
102	101		Form1:pForm1;
103	102
104	103		implementation
105	104
106	105		procedure NewForm1( var Result: PForm1; AParent: PControl );
107	106		begin
108	107		New(Result,Create);
109	108		with Result^ do
110	109		begin
111	110		{The appearance of a widget depends on its creating function}
112	111		Form := NewForm(AParent,cps);
113	112		Button := NewButton(Form,'&Click Me');
114	113		{Attach the MessageHandler}
115	114		Button.OnClick := ButtonClick;
116	115		{ The applet variable is the Application object
117	116		Assigning the main form to it assigns the main message loop to the form.}
118	117		Applet:=Form;
119	118		Form.Add2AutoFree(Result);
120	119		end;
121	120		end;
122	121
123	122		procedure TForm1.ButtonClick(Sender: PObj);
124	123		begin
125	124		ShowMessage('Ouch!');
126	125		end;
127	126
128	127		end.
129	128		```
130	129
131	130		So what's so special about it? Well, for one, compile this and look at the executable size. A similar program, Form + Button + ShowMessage compiled with Delphi 7 is 394 Kilobytes and it gets much worse for progressive newer versions of Delphi:2267 Kilobytes XE7-32, 3672 Kilobytes XE7-64. For comparison: the KOL version compiled with D7 is 156 times smaller than the VCL version compiled with XE7.
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133	132		Compiled with PPC386 it renders an executable of 48128 bytes. Compiled like:
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135	134		`ppc386 -Mdelphi -CX -XX -Xs -Os koldemo.dpr `
136	135
137	136		Compiled with PPCX64 for Windows it renders 65536 bytes. Compiled like:
138	137
139	138		`ppcx64 -Mdelphi -Rintel -CX -XX -Xs -Os koldemo.dpr`
140	139
141	140		The above examples are for an ANSI application. To compile a UNICODE application, simply add the UNICODE_CTRLS define, like:
142	141
143	142		`ppcx64 -Mdelphi -Rintel -dUNICODE_CTRLS -CX -XX -Xs -Os koldemo.dpr`
144	143
145	144		Note that especially for 64 bit, Free Pascal renders consistently smaller code than its expensive cousin. Also note that 32 bit Free Pascal has a slightly bigger runtime payload than its cousin. The size difference disappears when your application becomes more complex.
146	145
147	146		## Tip
148	147
149	148		For size, KOL defaults to an ugly system font. Here are multiple ways to remedy that:
150	149
151	150		``` pascal
152	151		{Add this code after the NewForm Function}
153	152		{Release the font}
154	153		Form.Font.ReleaseHandle;
155	154		{Assign the default windows GUI font object}
156	155		Form.Font.AssignHandle(GetStockObject(DEFAULT_GUI_FONT));
157	156		```
158	157
159	158		The second method is slightly more involved, but is the [\\|MSDN](http://msdn.microsoft.com/en-us/library/windows/desktop/dd144925%28v=vs.85%29.aspx) recommended way:
160	159
161	160		``` pascal
162	161		{Add this function}
163	162		function GetGuiFont:TLogFont;
164	163		var Metrics:TNonClientMetrics;
165	164		begin
166	165		Metrics.cbSize := SizeOf(Metrics);
167	166		SystemParametersInfo(SPI_GETNONCLIENTMETRICS, SizeOf(Metrics), @Metrics, 0);
168	167		Result := Metrics.lfMessageFont;
169	168		end;
170	169		{And call it after the form creation}
171	170		Form.Font.LogFontStruct :=GetGuiFont;
172	171		```
173	172
174	173		Fonts in KOL are objects of type TGraphicTool. This object can also represent pens and brushes. We can also create a new GraphicTool object representing the GUI font:
175	174
176	175		``` pascal
177	176		{The KOL way to assign the GUI font}
178	177		function GuiFont:PGraphicTool;
179	178		var Metrics:TNonClientMetrics;
180	179		begin
181	180		Result := NewFont;
182	181		Metrics.cbSize := SizeOf(Metrics);
183	182		SystemParametersInfo(SPI_GETNONCLIENTMETRICS, SizeOf(Metrics), @Metrics, 0);
184	183		Result.LogFontStruct := Metrics.lfMessageFont;
185	184		end;
186	185		{We can now assign the new font to the Form's font property}
187	186		Form.Font.Assign(GuiFont);
188	187		```
189	188
190	189		And this is the result: ![](/wiki-images/0/0f/Kolscreenshot.png)
191	190
192	191		---
193	192		From the Free Pascal wiki, page "KOL", as it stood on 2023-02-04 after a change by Alextp, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).
194	193		Category: Tutorials

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