{
SizeGripHWND.pas
Delphi component to add a size grip (like if you use a status bar) to the
lower right corner of any window control. This is intended for small
footprint non-VCL delphi applications and paints the size grip just using
the standard API functions (no layout control, no themes).
Version 1.2a - always find the most current version at
http://flocke.vssd.de/prog/code/pascal/sizegrip/
Copyright (C) 2005, 2006 Volker Siebert <flocke@vssd.de>
All rights reserved.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
}
unit SizeGripHWND;
interface
uses
Windows, Messages;
procedure SetWindowSizeGrip(hWnd: HWND; Enable: boolean);
implementation
const
SizeGripProp = 'SizeGrip';
type
TWndProc = function (hWnd: HWND; Msg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
PGripInfo = ^TGripInfo;
TGripInfo = record
OldWndProc: TWndProc;
Enabled: boolean;
GripRect: TRect;
end;
function SizeGripWndProc(hWnd: HWND; Msg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
var
Info: PGripInfo;
dc: HDC;
pt: TPoint;
// Invalidate the current grip rectangle
procedure InvalidateGrip;
begin
with Info^ do
if (GripRect.Right > GripRect.Left) and
(GripRect.Bottom > GripRect.Top) then
InvalidateRect(hWnd, @GripRect, true);
end;
// Update (and invalidate) the current grip rectangle
procedure UpdateGrip;
begin
with Info^ do
begin
GetClientRect(hWnd, GripRect);
GripRect.Left := GripRect.Right - GetSystemMetrics(SM_CXHSCROLL);
GripRect.Top := GripRect.Bottom - GetSystemMetrics(SM_CYVSCROLL);
end;
InvalidateGrip;
end;
function CallOld: LRESULT;
begin
Result := CallWindowProc(@Info^.OldWndProc, hWnd, Msg, wParam, lParam);
end;
begin
Info := PGripInfo(GetProp(hWnd, SizeGripProp));
if Info = nil then
Result := DefWindowProc(hWnd, Msg, wParam, lParam)
else if not Info^.Enabled then
Result := CallOld
else
begin
case Msg of
WM_NCDESTROY: begin
Result := CallOld;
SetWindowLong(hWnd, GWL_WNDPROC, LongInt(@Info^.OldWndProc));
RemoveProp(hWnd, SizeGripProp);
Dispose(Info);
end;
WM_PAINT: begin
Result := CallOld;
if wParam = 0 then
begin
dc := GetDC(hWnd);
DrawFrameControl(dc, Info^.GripRect, DFC_SCROLL, DFCS_SCROLLSIZEGRIP);
ReleaseDC(hWnd, dc);
end;
end;
WM_NCHITTEST: begin
pt.x := TSmallPoint(lParam).x;
pt.y := TSmallPoint(lParam).y;
ScreenToClient(hWnd, pt);
if PtInRect(Info^.GripRect, pt) then
Result := HTBOTTOMRIGHT
else
Result := CallOld;
end;
WM_SIZE: begin
InvalidateGrip;
Result := CallOld;
UpdateGrip;
end;
else
Result := CallOld;
end;
end;
end;
{ Note that SetWindowSizeGrip(..., false) does not really remove the hook -
it just sets "Enabled" to false. The hook plus all data is removed when
the window is destroyed.
}
procedure SetWindowSizeGrip(hWnd: HWND; Enable: boolean);
var
Info: PGripInfo;
begin
Info := PGripInfo(GetProp(hWnd, SizeGripProp));
if (Info = nil) and Enable then
begin
New(Info);
FillChar(Info^, SizeOf(TGripInfo), 0);
with Info^ do
begin
Info^.OldWndProc := TWndProc(Pointer(GetWindowLong(hWnd, GWL_WNDPROC)));
GetClientRect(hWnd, GripRect);
GripRect.Left := GripRect.Right - GetSystemMetrics(SM_CXHSCROLL);
GripRect.Top := GripRect.Bottom - GetSystemMetrics(SM_CYVSCROLL);
end;
SetProp(hWnd, SizeGripProp, Cardinal(Info));
SetWindowLong(hWnd, GWL_WNDPROC, LongInt(@SizeGripWndProc));
end;
if (Info <> nil) then
if Enable <> Info^.Enabled then
with Info^ do
begin
Enabled := Enable;
if (GripRect.Right > GripRect.Left) and
(GripRect.Bottom > GripRect.Top) then
InvalidateRect(hWnd, @GripRect, true);
end;
end;
end. |