AutoHotkey Community

#SingleInstance,Force
OnExit, GuiClose

Range1 := RGBRange(0xFFFFFF, 0xF00000, -100, "`n")
Range2 := RGBRange(0xF00000, 0x000000, -100, "`n")
   
Gui, Font,s36 w1000000
Loop,Parse,Range1,`n
   {
      Gui,Add,Text,yp+1 x50 BackgroundTrans c%A_LoopField%, _
   }
Loop,Parse,Range2,`n
   {
      Gui,Add,Text,yp+1 x50 BackgroundTrans c%A_LoopField%, _
   }
Gui, Show,, A

Return

RGBRange(x, y=0, c=0, delim=",")
{
   oif := A_FormatInteger
   SetFormat, Integer, H
   dr:=(y>>16&255)-(r:=x>>16&255)
   dg:=(y>>8&255)-(g:=x>>8&255)
   db:=(y&255)-(b:=x&255)
   d := sqrt(dr**2 + dg**2 + db**2)
   v := Floor(d/c)
   IfLessOrEqual, c, 0, SetEnv, c, % d/( v := c<-3 ? -1-Ceil(c) : 2 )
   s := c/d
   cr:=sqrt(d**2-dg**2-db**2)*s*((dr>0)*2-1)
   cg:=sqrt(d**2-dr**2-db**2)*s*((dg>0)*2-1)
   cb:=sqrt(d**2-dg**2-dr**2)*s*((db>0)*2-1)
   Loop %v%
   {
      u := SubStr("000000" SubStr( ""
      . ((Round(r+cr*A_Index)&255)<<16)
      | ((Round(g+cg*A_Index)&255)<<8)
      | (Round(b+cb*A_Index)&255), 3) ,-5)
      StringUpper, u, u
      x .= delim "0x" u
   }
   SetFormat, Integer, %oif%
   return x
}

GuiEscape:
GuiClose:
   ExitApp

Range1 := RGBRange("0xFFFFFF", 0xF00000, -100, "`n")
Range2 := RGBRange("0xF00000", 0x000000, -100, "`n")
;... AND/OR ...
SetFormat, Integer, H
x += 0