Custom Drawn Interface: what changed

Revision 1 to 2. Removed lines have a minus sign; added lines have a plus sign.

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1	1		> Warning: THIS INFORMATION IS EXTREMELY DATED AND NEEDS UPDATING as of 2015
2	2
3	3		## Introduction
4	4
5	5		LCL-CustomDrawn-Android has the following features:
6	6
7	7		- Backends for X11, Android and Windows and a partially working one for Cocoa, more can be added in the future
8	8		- Painting is done completely inside Lazarus without any interference from the native libraries except for text drawing. This assures a complete perfection of the executed drawings in all platforms and a uniform level of supported features
9	9		- Only 1 native window is utilized for each form, in the Android backend at the moment this is 1 native window for the entire application
10	10		- Utilizes the Lazarus Custom Drawn Controls for implementing the LCL standard controls
11	11		- Utilizes as it's painting engine the lcl parts: TLazIntfImage, TRawImage, lazcanvas and lazregions
12	12
13	13		## FAQ
14	14
15	15		### Diagram of the Custom Drawn Interface
16	16
17		-	~~<figure>~~
18		-	~~<img src="customdrawn_diagram.png" title="customdrawn_diagram.png" />~~
19		-	~~<figcaption>customdrawn_diagram.png</figcaption>~~
20		-	~~</figure>~~
	17	+	![](/wiki-images/8/85/Customdrawn_diagram.png)
21	18
22	19		Legend:
23	20
24	21		- Blue - New elements implemented as part of the LCL-CustomDrawn project
25	22		- Yellow - Pre-existing LCL elements
26	23		- Gray - System APIs
27	24
28	25		## The LCL-CustomDrawn Backends
29	26
30	27		LCL-CustomDrawn needs backends to implement the most basic parts of the widgetset. Each backend should implement the following minimal parts:
31	28
32	29		- TWidgetSet.Run, ProcessMessages, etc
33	30		- TForm
34	31		- TWinControl with all events
35	32		- TTrayIcon
36	33
37	34		### LCL-CustomDrawn-Android
38	35
39	36		This backend is working. See this page [[Custom Drawn Interface/Android]]
40	37
41	38		And also [[Android Programming]]
42	39
43	40		### LCL-CustomDrawn-X11
44	41
45	42		This backend is working. See [[Custom Drawn Interface/X11]]
46	43
47	44		### LCL-CustomDrawn-Cocoa
48	45
49	46		This backend is working.
50	47
51	48		### LCL-CustomDrawn-Windows
52	49
53	50		This backend is working.
54	51
55	52		### LCL-CustomDrawn-iPhone
56	53
57	54		This is planned, but not yet started.
58	55
59	56		## Canvas
60	57
61	58		TCanvas will be fully non-native in this widgetset and based on [[Developing with Graphics\|LazCanvas]]. All drawings to visual controls and on the OnPaint event of controls of the form are naturally double-buffered because the entire drawing of the form is first performed on an off-screen buffer and then copied in 1 operation to the form native canvas. In reality there is only 1 TLazCanvas for the entire form, but sub-controls will think they are on a separate canvas because the property BaseWindowOrg sets an internal start position of the canvas and also because all drawings will be clipped to reflect the size and shape of the sub-control.
62	59
63	60		### Getting the TLazCanvas object inside TCanvas
64	61
65	62		This works only in the LCL-CustomDrawn interface:
66	63
67	64		``` pascal
68	65		uses lazcanvas, lclintf;
69	66
70	67		var
71	68		MyLazCanvas: TLazCanvas:
72	69		begin
73	70		if nctLazCanvas in LCLIntf.GetAvailableNativeCanvasTypes(MyCanvas.Handle) then
74	71		begin
75	72		MyLazCanvas := TLazCanvas(LCLIntf.GetNativeCanvas(MyCanvas.Handle, nctLazCanvas));
76	73		// do something here with TLazCanvas
77	74		end;
78	75		```
79	76
80	77		### Drawing optimization roadmap
81	78
82	79		#### Optimizations already done
83	80
84	81		- Give 1 bitmap to each control and buffer the control images and only redraw them if invalidated. This greatly helps in large forms when invalidating only 1 control.
85	82		- Don't draw controls which are completely covered by other ones. Commits:
86	83		- <http://svn.freepascal.org/cgi-bin/viewvc.cgi?view=rev&root=lazarus&revision=36437>
87	84		- <http://svn.freepascal.org/cgi-bin/viewvc.cgi?view=rev&root=lazarus&revision=36455>
88	85		- Change the control bitmaps to use the native format (with ifdefs for ARGB32 for alpha blending support). This was implemented together with the next optimization:
89	86		- Optimize the case of drawing a bitmap to a canvas, when the pixel formats match and the clip rect is inexistent or rectangular. The magnifier full painting went from 630ms to 477ms for me.
90	87		- <http://svn.freepascal.org/cgi-bin/viewvc.cgi?view=rev&root=lazarus&revision=36576>
91	88		- <http://svn.freepascal.org/cgi-bin/viewvc.cgi?view=rev&root=lazarus&revision=36578>
92	89		- Optimize rectangle area filling if the clip rect is inexistent or rectangular. Decreased the drawing of a fullscreen form in X11 with 4 buttons from 95ms to 33ms for me
93	90		- <http://svn.freepascal.org/cgi-bin/viewvc.cgi?view=rev&root=lazarus&revision=36580>
94	91
95	92		#### Optimizations to be done
96	93
97	94		- Buffer the native bitmap of the form instead of generating it on each operation
98	95		- Reuse the buffered native bitmap contents if they don't change
99	96		- Support invalidating only a rectangle instead of the entire control
100	97
101	98		## Font rendering
102	99
103	100		When the define CD_UseNativeText is activated, LCL-CustomDrawn will use the native text rendering of the platform as provided by the backend. If it isn't activated, then it will use [[LazFreeType]] to render the text. The define is automatically activated for some backends if convenient when using them.
104	101
105	102		## Message and Common Dialogs
106	103
107	104		Message and Common Dialogs might be native if this is considered very convenient for the backend. If not, they will be non-native. At the moment the Android backend has native message boxes.
108	105
109	106		## Windowed visual controls
110	107
111	108		All Windowed visual controls (TButton, TPageControl, etc) will be based in the [[Lazarus Custom Drawn Controls]]
112	109
113	110		## Conditional defines accepted by LCL-CustomDrawn
114	111
115	112		One easy way to set a conditional define for the LCL-CustomDrawn is to define it in the file lcl/interfaces/customdrawn/customdrawndefines.inc
116	113
117	114		Here are defines which affect the functionality offered by this interface:
118	115
119	116		- CD_UseNativeText - Activates using native text instead of PasFreeType. This define will be automatically set if convenient for a particular backend, don't set it manually unless you know what you are doing.
120	117
121	118		And here debug information defines:
122	119
123	120		- VerboseCDPaintProfiler - Adds profiling information to indicate how fast the paint event is processed
124	121		- VerboseCDWinAPI - Extended verbose information for LCLIntf calls, except those which are covered by one of these defines instead:
125	122		- VerboseCDText - Verbose info for text winapi calls
126	123		- VerboseCDDrawing - Verbose info for Canvas and drawing operations
127	124		- VerboseCDBitmap - Verbose info for Bitmap and rawimage creation and handling
128	125		- VerboseCDForms - Extended verbose information for TWSCustomForm methods and about the non-native form from customdrawnproc (when utilized)
129	126		- VerboseCDEvents - Extended verbose information for native events (for example mouse click, key input, etc). This excludes the paint event
130	127		- VerboseCDPaintEvent - Debug info for the paint event
131	128		- VerboseCDApplication - Verbose info for App routines from the Widgetset object
132	129		- VerboseCDMessages - Verbose info for messages from the operating system (Paint, keyboard, mouse)
133	130
134	131		## Screenshots
135	132
136		-	~~<figure>~~
137		-	~~<img src="Lazclock_customdrawn.png" title="Lazclock_customdrawn.png" />~~
138		-	~~<figcaption>Lazclock_customdrawn.png</figcaption>~~
139		-	~~</figure>~~
	133	+	![](/wiki-images/0/05/Lazclock_customdrawn.png)
140	134
141	135		![](/wiki-images/4/4c/Lcl_android_30_mar.png) ![](/wiki-images/d/df/Vpr-android.png)
142	136
143	137		## See Also
144	138
145	139		- [[Lazarus Custom Drawn Controls]]
146	140
147	141		---
148	142		From the Free Pascal wiki, page "Custom Drawn Interface", as it stood on 2020-02-08 after a change by Trev, 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).
149	143		Category: Custom Drawn

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