Convert color to/from HTML: what changed

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

Title: Convert color to/from HTML

New		Line
1	+	This unit has functions which convert TColor value to/from HTML color string: \#rrggbb. It can convert HTML string \#rgb too.
2	+
3	+	Author: User:Alextp
4	+
5	+	``` pascal
6	+	unit ATStringProc_HtmlColor;
7	+
8	+	{$mode objfpc}{$H+}
9	+
10	+	interface
11	+
12	+	uses
13	+	Classes, SysUtils, Graphics;
14	+
15	+	//convert TColor -> HTML color string #rrggbb
16	+	function SColorToHtmlColor(Color: TColor): string;
17	+	//convert string which starts with HTML color token #rgb, #rrggbb -> TColor, get len of color-string
18	+	function SHtmlColorToColor(s: string; out Len: integer; Default: TColor): TColor;
19	+
20	+	implementation
21	+
22	+	function IsCharWord(ch: char): boolean;
23	+	begin
24	+	Result:= ch in ['a'..'z', 'A'..'Z', '_', '0'..'9'];
25	+	end;
26	+
27	+	function IsCharHex(ch: char): boolean;
28	+	begin
29	+	Result:= ch in ['0'..'9', 'a'..'f', 'A'..'F'];
30	+	end;
31	+
32	+	function SColorToHtmlColor(Color: TColor): string;
33	+	var
34	+	N: Longint;
35	+	begin
36	+	if Color=clNone then
37	+	begin Result:= ''; exit end;
38	+	N:= ColorToRGB(Color);
39	+	Result:= '#'+
40	+	IntToHex(Red(N), 2)+
41	+	IntToHex(Green(N), 2)+
42	+	IntToHex(Blue(N), 2);
43	+	end;
44	+
45	+	function SHtmlColorToColor(s: string; out Len: integer; Default: TColor): TColor;
46	+	var
47	+	N1, N2, N3: integer;
48	+	i: integer;
49	+	begin
50	+	Result:= Default;
51	+	Len:= 0;
52	+	if (s<>'') and (s[1]='#') then Delete(s, 1, 1);
53	+	if (s='') then exit;
54	+
55	+	//delete after first nonword char
56	+	i:= 1;
57	+	while (i<=Length(s)) and IsCharWord(s[i]) do Inc(i);
58	+	Delete(s, i, Maxint);
59	+
60	+	//allow only #rgb, #rrggbb
61	+	Len:= Length(s);
62	+	if (Len<>3) and (Len<>6) then exit;
63	+
64	+	for i:= 1 to Len do
65	+	if not IsCharHex(s[i]) then exit;
66	+
67	+	if Len=6 then
68	+	begin
69	+	N1:= StrToInt('$'+Copy(s, 1, 2));
70	+	N2:= StrToInt('$'+Copy(s, 3, 2));
71	+	N3:= StrToInt('$'+Copy(s, 5, 2));
72	+	end
73	+	else
74	+	begin
75	+	N1:= StrToInt('$'+s[1]+s[1]);
76	+	N2:= StrToInt('$'+s[2]+s[2]);
77	+	N3:= StrToInt('$'+s[3]+s[3]);
78	+	end;
79	+
80	+	Result:= RGBToColor(N1, N2, N3);
81	+	end;
82	+
83	+	end.
84	+	```
85	+
86	+	## See also
87	+
88	+	- Talk:Convert_color_to/from_HTML
89	+
90	+	---
91	+	From the Free Pascal wiki, page "Convert color to/from HTML", 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).

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