How to set the desktop color
lazarus / 39-Graphics

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zxandris · 2024-12-08 18:55

Hello, I was wondering if anyone knows how to set the desktop color in
windows please?

Currently I have no idea how to do this.  I have a little routine that
sets the desktop background, and I would really like to be able to set
the desktop background color too.

Any help would be gratefully appreciated

CJ

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Fibonacci · 2024-12-08 23:24

How about that

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
Windows, SysUtils, Classes; procedure set_desktopbg_solid_color(color:
dword);const  bitmap =
#$42#$4D#$3A#$00#$00#$00#$00#$00#$00#$00#$36#$00#$00#$00#$28#$00 
+#$00#$00#$01#$00#$00#$00#$01#$00#$00#$00#$01#$00#$18#$00#$00#$00 
+#$00#$00#$04#$00#$00#$00#$23#$2E#$00#$00#$23#$2E#$00#$00#$00#$00 
+#$00#$00#$00#$00#$00#$00;var  temp: string;begin  with
TMemoryStream.Create do begin    Write(bitmap[1], length(bitmap));   
color := SwapEndian(color) shr 8;    Write(color, 4);    temp :=
ExtractFileDir(paramstr(0))+'\1x1.bmp';    SaveToFile(temp);   
SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, @temp[1],
SPIF_UPDATEINIFILE or SPIF_SENDWININICHANGE);    DeleteFile(temp);   
Free;  end;end; const  clRed = $0000FF;  clLime = $00FF00; begin 
while true do begin    set_desktopbg_solid_color(clRed);   
sleep(1000);    set_desktopbg_solid_color(clLime);    sleep(1000); 
end;end.

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zxandris · 2024-12-08 23:27

Not entirely sure I'm reading this right but it appears that sets the
wallpaper with a colored bitmap.  That is unfortunately definitely not
what I want.  In control panel you can set the background color of the
desktop seperately from the wallpaper.  That's what I'm trying to do.

But thank you for the reply, and please do tell me if I'm not reading
that right.

CJ

Quote from: Fibonacci on December 09, 2024, 12:24:59 amHow about that

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
Windows, SysUtils, Classes; procedure set_desktopbg_solid_color(color:
dword);const  bitmap =
#$42#$4D#$3A#$00#$00#$00#$00#$00#$00#$00#$36#$00#$00#$00#$28#$00 
+#$00#$00#$01#$00#$00#$00#$01#$00#$00#$00#$01#$00#$18#$00#$00#$00 
+#$00#$00#$04#$00#$00#$00#$23#$2E#$00#$00#$23#$2E#$00#$00#$00#$00 
+#$00#$00#$00#$00#$00#$00;var  temp: string;begin  with
TMemoryStream.Create do begin    Write(bitmap[1], length(bitmap));   
color := SwapEndian(color) shr 8;    Write(color, 4);    temp :=
ExtractFileDir(paramstr(0))+'\1x1.bmp';    SaveToFile(temp);   
SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, @temp[1],
SPIF_UPDATEINIFILE or SPIF_SENDWININICHANGE);    DeleteFile(temp);   
Free;  end;end; const  clRed = $0000FF;  clLime = $00FF00; begin 
while true do begin    set_desktopbg_solid_color(clRed);   
sleep(1000);    set_desktopbg_solid_color(clLime);    sleep(1000); 
end;end.

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TRon · 2024-12-08 23:42

Quote from: zxandris on December 09, 2024, 12:27:51 amIn control panel
you can set the background color of the desktop seperately from the
wallpaper.  That's what I'm trying to do.
Then do it in the same way but in code, see also these SO answers.

There is a registry class.

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Fibonacci · 2024-12-08 23:50

Oh

This color can be obtained by the DwmGetColorizationColor() function,
but there is no Set variant of this function, so you need to do it
through the registry

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zxandris · 2024-12-08 23:57

Okay from that link I came up with

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
SetDesktopColor(const clr : TColor);var   strColor : String;   r :
TRegistry;begin      strColor := clrToRGBString(clr);      r :=
TRegistry.Create;      try         r.RootKey := HKEY_CURRENT_USER;   
    r.OpenKey('Control Panel\Colors\', false);       
 r.WriteString('Background', strColor);      finally        r.free;  
  end;      SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, nil,
SPIF_SENDWININICHANGE);end;                                          
                               
Now it sets the registry key fine, but it doesn't actualy update the
desktop color.  Would anyone know how to trigger windows into
realising that's changed because I thought
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i      
SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, nil,
SPIF_SENDWININICHANGE); 
Would do that, but it doesn't.  Now in further searching I found
SetSysColors, but I don't have any reference for actually using this
function.  Would anyone know how to use that perhaps.  Any help would
be appreciated.  So far I've got a nice procedure that actually does
set the color but it's not updating.  I assume that SetSysColors would
do that, but honestly a nice call to refresh the desktop background
somehow would be most excellent.  I am NOT very good with actual
windows calls. lol

CJ


Quote from: TRon on December 09, 2024, 12:42:36 amQuote from: zxandris
on December 09, 2024, 12:27:51 amIn control panel you can set the
background color of the desktop seperately from the wallpaper.  That's
what I'm trying to do.
Then do it in the same way but in code, see also these SO answers.

There is a registry class.

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zxandris · 2024-12-09 00:04

Code: [Select]int aElements[1] = {COLOR_BACKGROUND};
DWORD aNewColors[1];
aNewColors[0] = RGB(0x80, 0x00, 0x80);  // dark purple
SetSysColors(1, aElements, aNewColors);

Seems to be the c way of doing things but?? I don't know C I barely
know pascal lol.  Anyone that could help would be very appreciated in
converting that and making it perhaps so I can pass a TColor to be
converted and set.  But I would guess I still have to notify windows
of the update.

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TRon · 2024-12-09 00:12

Quote from: zxandris on December 09, 2024, 01:04:16 amSeems to be the
c way of doing things
Ah yes that seems to be a better approach, see also here and here

According to that documentation a systemwide message is send so in
theory the example should take care of things automatically.

However, do note this:
QuoteWindows 10 or greater: This value is not supported.

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zxandris · 2024-12-09 00:21

Okay so I really don't know how to send a windows message I think I
found the message I want, but in this case

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, nil, WM_SYSCOLORCHANGE);
That doesn't work and frankly I'm pretty sure the first spi_ thing
isn't the right one and for bonus points I'm actually on windows 11,
so I'm really not sure if I got this right.  now if I got that right
WM_ message I'm afraid I really don't know how to properly send it at
all.

Please help this poor fool   I've no experience in this sort of
thing.  I've been programming pascal for years but recently it's come
to my attention how much i DON'T know.

CJ

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TRon · 2024-12-09 00:26

Well, keep in mind that for me personally windows is just a theory for
me as I don't have/use it anymore (so unfortunately can't test
either).

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zxandris · 2024-12-09 00:29

From what I can read that windows10+ is overly complicated to say the
least, since the reg values are still there I would assume you can
trigger something to make it refresh... it's quite frustrating you'd
think this would be simple

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zxandris · 2024-12-09 00:40

Ok I think I'm getting closer but I know this doesn't work but I feel
like it's close, so anyone that can correct me I'd love ya

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
SystemParametersInfo(WM_SYSCOLORCHANGE, 0, nil, WM_SETTINGCHANGE);

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Fibonacci · 2024-12-09 01:19

Got it. Now your turn - figure out the colors, create functions and
share

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
SysUtils, Registry; function tohex(p: pointer; len: dword):
string;var  i: integer;begin  result := '';  for i := 0 to len-1 do
result += inttohex(pbyte(p+i)^, 2);end; function tobin(s: string):
string;var  i: integer;begin  result := '';  i := 1;  while i <
length(s) do begin    result += chr(strtoint('$'+copy(s, i, 2)));   
inc(i, 2);  end;end; var  s: string; begin  with TRegistry.Create do
begin    RootKey := HKEY_CURRENT_USER;   
OpenKey('SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Accent',
false);     // read    //setlength(s, 32);   
//ReadBinaryData('AccentPalette', s[1], 32);    //writeln('palette =
', tohex(@s[1], length(s)));    //writeln('StartColorMenu = ',
ReadInteger('StartColorMenu'));    //writeln('AccentColorMenu = ',
ReadInteger('AccentColorMenu'));     // apply yellow    s := tobin('FF
E8A800FFE08C00FFD35C00FFB90000BA890000805E00004D38000000B29400');   
WriteBinaryData('AccentPalette', s[1], length(s));   
WriteInteger('StartColorMenu', -16741958);   
WriteInteger('AccentColorMenu', -16729601);     // apply green    //s
:= tobin('C1F7DD00A6F7D00068E3A80000CC6A000087460000522A00002B1600E300
8C00');    //WriteBinaryData('AccentPalette', s[1], length(s));   
//WriteInteger('StartColorMenu', -12155136);   
//WriteInteger('AccentColorMenu', -9778176);     Free;  end;end.

Yellow:
https://coolors.co/e8a800-e08c00-d35c00-b90000-890000-5e0000-380000-
b29400

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zxandris · 2024-12-09 01:34

I'm sorry but I have quite literally zero idea how to convert a TColor
to a binary number that would work with that.  Also I might be
misreading this but it sets the accent color which I may be wrong will
only work if you're actually got the accent being set option by the
desktop wallaper??

Quote from: Fibonacci on December 09, 2024, 02:19:38 amGot it. Now
your turn - figure out the colors, create functions and share

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses
SysUtils, Registry; function tohex(p: pointer; len: dword):
string;var  i: integer;begin  result := '';  for i := 0 to len-1 do
result += inttohex(pbyte(p+i)^, 2);end; function tobin(s: string):
string;var  i: integer;begin  result := '';  i := 1;  while i <
length(s) do begin    result += chr(strtoint('$'+copy(s, i, 2)));   
inc(i, 2);  end;end; var  s: string; begin  with TRegistry.Create do
begin    RootKey := HKEY_CURRENT_USER;   
OpenKey('SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Accent',
false);     // read    //setlength(s, 32);   
//ReadBinaryData('AccentPalette', s[1], 32);    //writeln('palette =
', tohex(@s[1], length(s)));    //writeln('StartColorMenu = ',
ReadInteger('StartColorMenu'));    //writeln('AccentColorMenu = ',
ReadInteger('AccentColorMenu'));     // apply yellow    s := tobin('FF
E8A800FFE08C00FFD35C00FFB90000BA890000805E00004D38000000B29400');   
WriteBinaryData('AccentPalette', s[1], length(s));   
WriteInteger('StartColorMenu', -16741958);   
WriteInteger('AccentColorMenu', -16729601);     // apply green    //s
:= tobin('C1F7DD00A6F7D00068E3A80000CC6A000087460000522A00002B1600E300
8C00');    //WriteBinaryData('AccentPalette', s[1], length(s));   
//WriteInteger('StartColorMenu', -12155136);   
//WriteInteger('AccentColorMenu', -9778176);     Free;  end;end.

Yellow:
https://coolors.co/e8a800-e08c00-d35c00-b90000-890000-5e0000-380000-
b29400

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Fibonacci · 2024-12-09 01:42

Quote from: zxandris on December 09, 2024, 02:34:23 amI'm sorry but I
have quite literally zero idea how to convert a TColor to a binary
number that would work with that.

You know HTML hex colors? RGB? TColor is the same, but in reverse, and
with alpha channel byte. Look at the link to coolors.co, I put there
all these colors but without the first byte (presumably the alpha
channel).

Quote from: zxandris on December 09, 2024, 02:34:23 amI might be
misreading this but it sets the accent color which I may be wrong will
only work if you're actually got the accent being set option by the
desktop wallaper??

If thats not what you wanted then Im lost.. Run the code and see for
yourself.