VCL Styles Utils Project – New Addition : Patch for System colors.

December 7, 2013 by Rodrigo 17 Comments

Introduction

A result of the work in a new sub project of the VCL Styles Utils , many new features as been added to the library, One of my favorites is a patch for the GetSysColor WinApi function. This fix replace the original call to this function by a jump to the StyleServices.GetSystemColor method replacing the original system colors by the current VCL Style colors. One of the advantages of use this fix is which the controls uses the proper VCL Style highlight color.

Screenshots

Check these controls with the VCL Styles

Now using the Vcl.Styles.Hooks unit

TColorBox

Source Code

This is the actual source code of the Vcl.Styles.Hooks unit which includes the patch to the GetSysColor function. To use this unit in your code you must add the KOLDetours unit too.

unit Vcl.Styles.Hooks;

interface

implementation

uses
  KOLDetours,
  WinApi.Windows,
  Vcl.Styles,
  Vcl.Themes;

var
  TrampolineGetSysColor:  function (nIndex: Integer): DWORD; stdcall;
  GetSysColorOrgPointer : Pointer = nil;

function InterceptGetSysColor(nIndex: Integer): DWORD; stdcall;
begin
  if StyleServices.IsSystemStyle then
   Result:= TrampolineGetSysColor(nIndex)
  else
   Result:= StyleServices.GetSystemColor(nIndex or Integer($FF000000));
end;

initialization
 if StyleServices.Available then
 begin
   GetSysColorOrgPointer  := GetProcAddress(GetModuleHandle('user32.dll'), 'GetSysColor');
   @TrampolineGetSysColor := InterceptCreate(GetSysColorOrgPointer, @InterceptGetSysColor);
 end;
finalization
 if GetSysColorOrgPointer<>nil then
  InterceptRemove(@TrampolineGetSysColor, @InterceptGetSysColor);

end.