带有系统阴影的圆形表格

Question

我尝试使用SetWindowRgn，但我做不到。

可以这样做（前2个角是圆角的，窗户有阴影）就像这张照片一样？

Answer 1

以下是如何使用阴影设置窗口区域的代码示例：
（注意：表格BorderStyle假定为bsNone，而不是重新调整大小

type
TForm1 = class(TForm)
  procedure FormCreate(Sender: TObject);
private
  procedure CreateFlatRoundRgn;
protected
  procedure CreateParams(var Params: TCreateParams); override;
public
end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure ExcludeRectRgn(var Rgn: HRGN; LeftRect, TopRect, RightRect, BottomRect: Integer);
var
  RgnEx: HRGN;
begin
  RgnEx := CreateRectRgn(LeftRect, TopRect, RightRect, BottomRect);
  CombineRgn(Rgn, Rgn, RgnEx, RGN_OR);
  DeleteObject(RgnEx);
end;

procedure TForm1.CreateFlatRoundRgn;
const
  CORNER_SIZE = 6;
var
  Rgn: HRGN;
begin
  with BoundsRect do
  begin
    Rgn := CreateRoundRectRgn(0, 0, Right - Left + 1, Bottom - Top + 1, CORNER_SIZE, CORNER_SIZE);
    // exclude left-bottom corner
    ExcludeRectRgn(Rgn, 0, Bottom - Top - CORNER_SIZE div 2, CORNER_SIZE div 2, Bottom - Top + 1);
    // exclude right-bottom corner
    ExcludeRectRgn(Rgn, Right - Left - CORNER_SIZE div 2, Bottom - Top - CORNER_SIZE div 2, Right - Left , Bottom - Top);
  end;
  // the operating system owns the region, delete the Rgn only SetWindowRgn fails
  if SetWindowRgn(Handle, Rgn, True) = 0 then
    DeleteObject(Rgn);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  BorderStyle := bsNone;
  CreateFlatRoundRgn;
end;

procedure TForm1.CreateParams(var Params: TCreateParams);
const
  CS_DROPSHADOW = $00020000;
begin
  inherited CreateParams(Params);
  with Params do
  begin
    Style := WS_POPUP;
    WindowClass.Style := WindowClass.Style or CS_DROPSHADOW;
  end;
end;

绘制自定义阴影的另一种方法是设置窗口WS_EX_LAYERED并使用UpdateLayeredWindow

以下是very good example如何完成（源代码使用C ++，但很容易理解）

对于更复杂的形状，您可以在表单上使用PNG图片并Alpha Blend。

---

修改

调整WS_POPUP窗口的大小是痛苦的世界...... 您有几个选择：

• 撰写WM_NCHITEST handler
• 使用WM_Syscommand $F008调整大小（在链接上方）或$F012到move the Window。
• 使用WS_EX_STATICEDGE and WS_SIZEBOX个样式。

注意您需要在重新调整窗口区域时重新创建窗口区域（例如OnResize事件）。

Answer 2

将dwm用于无边界Windows应用程序。示例代码：

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
  private
    { Private declarations }
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    procedure WndProc(var Message: TMessage); override;
  public
    { Public declarations }
  end;

  TMARGINS = record
    leftWidth: integer;
    rightWidth: integer;
    topHeight: integer;
    bottomHeight: integer;
  end;
  LPCVOID = Pointer;

  function DwmExtendFrameIntoClientArea(hWnd: HWND; const pMarInset: TMARGINS): HRESULT;
    stdcall; external 'dwmapi.dll';
  function DwmSetWindowAttribute(hWnd: HWND; dwAttribute: DWORD; pvAttribute: LPCVOID;
    cbAttribute: DWORD): HRESULT; stdcall; external 'dwmapi.dll';
  function DwmIsCompositionEnabled(out pfEnabled: BOOL): HRESULT; stdcall; external 'dwmapi.dll';

const
  CS_DROPSHADOW = $00020000;
  HTCLIENT = $1;

var
  Form1: TForm1;
  m_aeroEnabled: boolean;

implementation

{$R *.DFM}

{ TForm1 }

function CheckAeroEnabled(): boolean;
var
  Enabled: longbool;
begin
  if (Win32MajorVersion >= 6) then
  begin
    Enabled := False;
    DwmIsCompositionEnabled(Enabled);
    result := Enabled;
  end
  else
    result := False;
end;

procedure TForm1.CreateParams(var Params: TCreateParams);

begin
  inherited;
  m_aeroEnabled := CheckAeroEnabled();
  if (not m_aeroEnabled) then
    Params.WindowClass.style := Params.WindowClass.style + CS_DROPSHADOW;

end;

procedure TForm1.WndProc(var Message: TMessage);
var
  margins: TMARGINS;
  v: integer;
begin
  case (Message.Msg) of
    WM_NCPAINT: if (m_aeroEnabled) then
      begin
        v := 2;
        DwmSetWindowAttribute(Self.Handle, 2, @v, 4);

        margins.bottomHeight := 1;
        margins.leftWidth := 0;
        margins.rightWidth := 0;
        margins.topHeight := 0;

        DwmExtendFrameIntoClientArea(Self.Handle, margins);
      end;
  end;

  inherited;

  //To allow move form without Caption.
  if (Message.Msg = WM_NCHITTEST) and (Message.result = HTCLIENT) then
    Message.result := HTCAPTION;

end;

end.