1

当我有这个时:

if not _nightMode then
  TStyleManager.TrySetStyle('Windows', False);

我可以在页面控件上进行所有者绘制:

procedure TMyMainForm.pcDetailedDrawTab(Control: TCustomTabControl; TabIndex: Integer;
    const Rect: TRect; Active: Boolean);
var
  can: TCanvas;
  cx, by: Integer;
  aclr: TColor;
begin
  if pcDetailed.Pages[TabIndex] = tsActualData then begin
    can := pcDetailed.Canvas;
    cx := Rect.Left + Rect.Width div 2;
    by := Rect.Bottom - 2;
    if _nightMode then aclr := clWhite else aclr := clBlack;
    can.Pen.Color := aclr;
    can.Brush.Color := aclr;
    can.Polygon([Point(cx - 10, by - 10), Point(cx + 10, by - 10), Point(cx, by)]);
  end;
end;

当我有这个时:

if _nightMode then
  TStyleManager.TrySetStyle('Cobalt XEMedia', False);

我绘制的三角形丢失了。

如何使用任何 VCL 样式绘制三角形?

德尔福 10 西雅图。

4

1 回答 1

3

When Stylesother than the native 'Windows'-style are chosen a StyleHook-class will begin to hook paint relevant windows messages to controls. 不同的控制类有不同StyleHook的类。

如果TPageControlTTabControlStyleHook. hook-class-combinationTCustomStyleEngine.RegisterStyleHook(TCustomTabControl, TTabControlStyleHook);在 的类构造函数中注册TCustomTabControl。这个钩子类覆盖了控件绘制,因为它会在TCustomTabControl启用样式时绘制自身。

可以做的是取消注册默认值TStyleHookClass并注册一个让开发人员绘制的:

  TCustomStyleEngine.UnRegisterStyleHook(TCustomTabControl, TTabControlStyleHook);
  TCustomStyleEngine.RegisterStyleHook(TCustomTabControl, TMyTabControlStyleHook);

以下是哪里TMyTabControlStyleHook

type
  TMyTabControlStyleHook = class(TTabControlStyleHook)
  public
    constructor Create(AControl: TWinControl); override;
  end;

constructor TMyTabControlStyleHook.Create(AControl: TWinControl);
begin
  inherited Create(AControl);
  OverridePaint := False;
end;

然而,这并不完全等同于仅绘制 中的选项卡TPageControl,因为TTabControlStyleHook负责绘制完整的TPageControl控件。

但是TTabControlStyleHookprocedure DrawTab(Canvas: TCanvas; Index: Integer); virtual;which 可以被覆盖。

type
  TMyTabControlStyleHook = class(TTabControlStyleHook)
  strict protected
    procedure DrawTab(Canvas: TCanvas; Index: Integer); override;
  end;

procedure TMyTabControlStyleHook.DrawTab(Canvas: TCanvas; Index: Integer);
begin
  DrawTabOverride(Canvas, Index, TabRect[Index], TCustomTabControl(Control).MouseInClient);
end;

哪里DrawTabOverride有这样的东西

procedure DrawTabOverride(Canvas: TCanvas;
  TabIndex: Integer; const Rect: TRect; Active: Boolean);

因此可以OnDrawTab在绘制原生时的事件中调用它,并且在样式化时可以在 StyleHook 类中调用它DrawTab

于 2017-10-19T09:18:18.710 回答