Skia: what changed

Revision 0 to 1. Removed lines have a minus sign; added lines have a plus sign.

Title: Skia

New		Line
1	+	# Overview
2	+
3	+	[Skia](https://skia.org)is an open source cross platform 2D graphics library used for example by Chrome and Firefox.
4	+
5	+	The [skia4delphi](https://skia4delphi.org/)project provides shared and static libraries and Pascal units to access Skia with FPC and Delphi.
6	+
7	+	In lazarus-ccr there are Lazarus packages and LCL components.
8	+
9	+	# Setup
10	+
11	+	## Requirements
12	+
13	+	- FPC 3.3.1
14	+	- If you want to install the design time package, the IDE must be compiled with fpc 3.3.1.
15	+
16	+	## Download sk4d dynamic library
17	+
18	+	The sk4d dynamic library is provided by the skia4delphi project. Their installer is for Windows Delphi users. For Lazarus download the sources or clone the git:
19	+
20	+	1. Go to <https://github.com/skia4delphi/skia4delphi/releases>
21	+	2. Download the Source code (zip)
22	+	3. Unpack the skia4delphi-6.1.0.zip
23	+	4. You will find the sk4d library in Binary/Shared/YourPlatform
24	+
25	+	Your project must be able to find the library:
26	+
27	+	- Linux: Set the LD_LIBRARY_PATH variable:
28	+
29	+	`bash: export LD_LIBRARY_PATH=/home/user/skia4delphi-6.1.0/Binary/Shared/Linux64/`
30	+
31	+	- MacOS: Copy the skia4delphi-6.1.0/Binary/Shared/OSX64/libsk4d.dylib to the project folder or create a symlink
32	+	- Windows: Copy the skia4delphi-6.1.0/Binary/Shared/Win64/sk4d.dll to the project folder
33	+
34	+	## Download the Lazarus packages
35	+
36	+	Download lazarus-ccr via svn:
37	+
38	+	`svn checkout `[`https://svn.code.sf.net/p/lazarus-ccr/svn/`](https://svn.code.sf.net/p/lazarus-ccr/svn/)` lazarus-ccr-svn`
39	+
40	+	The skia files are in the directory lazarus-ccr-svn/components/skia .
41	+
42	+	There are three Lazarus packages:
43	+
44	+	- design/Skia.LCL.Design.lpk - the IDE addon
45	+	- src/Skia.LCL.lpk - contains the LCL controls like TSkPaintBox and TSkCustomWinControl
46	+	- skia4d_package/Skia.lpk - the units from skia4delphi
47	+
48	+	## Install Skia.LCL.Design
49	+
50	+	This is optional.
51	+
52	+	Requirements:
53	+
54	+	- The IDE is compiled with fpc 3.3.1
55	+	- the sk4d library can be found by the Lazarus executable, otherwise the IDE will not start.
56	+
57	+	Install the package Skia.LCL.Design.lpk in the IDE:
58	+
59	+	- Open the design/Skia.LCL.Design.lpk via IDE menu Package / Open Package File (lpk)
60	+	- Then click the button Use and Install
61	+	- Restart the IDE
62	+
63	+	You will find a new page Skia in the component palette.
64	+
65	+	# TSkPaintBox
66	+
67	+	This is a TGraphicControl - a lcl control without its own handle. Useful if you just want to draw something with skia. Set the OnDraw event
68	+
69	+	``` pascal
70	+	procedure TForm1.FormCreate(Sender: TObject);
71	+	begin
72	+	MySkPaintBox:=TSkPaintBox.Create(Self);
73	+	with MySkPaintBox do begin
74	+	Name:='MySkPaintBox';
75	+	OnDraw:=@MySkPaintBoxDraw;
76	+	SetBounds(10,10,50,50);
77	+	Parent:=Self;
78	+	end;
79	+	end;
80	+
81	+	procedure TForm1.MySkPaintBoxDraw(Sender: TObject; const aCanvas: ISkCanvas; const aDest: TRectF; const aOpacity: Single);
82	+	begin
83	+	aCanvas.Clear(TAlphaColors.Red);
84	+	end;
85	+	```
86	+
87	+	Note: the Opacity is not yet supported.
88	+
89	+	# TSkCustomWinControl
90	+
91	+	This is TCustomControl - a lcl base class for custom controls with own handle and scrollbars. Override the DrawContent and Invalidate methods:
92	+
93	+	``` pascal
94	+	type
95	+	TMySkiaControl = class(TSkCustomWinControl)
96	+	public
97	+	procedure DrawContent(const ACanvas: ISkCanvas; const {%H-}ADest: TRectF;
98	+	const AOpacity: Single); override;
99	+	procedure Invalidate; override;
100	+	end;
101	+	...
102	+
103	+	procedure TMySkiaControl.DrawContent(const ACanvas: ISkCanvas; const ADest: TRectF; const AOpacity: Single);
104	+	begin
105	+	// your drawing code
106	+	aCanvas.Clear(TAlphaColors.White);
107	+	end;
108	+
109	+	procedure TMySkiaControl.Invalidate;
110	+	begin
111	+	inherited Invalidate;
112	+	Render.Redraw; // force a redraw
113	+	end;
114	+	```
115	+
116	+	Note: the Opacity is not yet supported.
117	+
118	+	---
119	+	From the Free Pascal wiki, page "Skia", as it stood on 2024-04-26 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).

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