如何消除TSpeedButton控件的图片闪烁问题？

问题复现步骤 #

• 在新VCL窗体中添加TPanel，设置Align = alClient。
• 在面板上添加TSpeedButton，为其Glyph属性分配一张bmp图片。（可选但效果更明显：设置Flat = True）
• 运行程序，拖动窗体右下角调整大小，TSpeedButton中的图片会出现闪烁。

尝试过无效的方案 #

• 该控件没有DoubleBuffered属性
• 无法设置WS_EX_COMPOSITED，因为它是TGraphicControl而非TWinControl
• 不会接收WM_ERASEBKGND消息

说明：实际使用的是TPngSpeedButton，但问题根源在于TSpeedButton，故以此为例。

可行解决方案 #

方案1：给父面板启用双缓冲

虽然TSpeedButton本身没有双缓冲属性，但它的绘制完全依赖父控件的画布。给父TPanel开启双缓冲，能大幅减少整体重绘时的闪烁。代码设置方式：

Panel1.DoubleBuffered := True;

如果是较新的Delphi版本，也可以直接在DFM文件中给TPanel添加DoubleBuffered = True属性。

方案2：自定义优化版TSpeedButton

重写TSpeedButton的Paint方法，避免不必要的背景擦除操作，直接基于父控件背景绘制：

type
  TNoFlashSpeedButton = class(TSpeedButton)
  protected
    procedure Paint; override;
  end;

procedure TNoFlashSpeedButton.Paint;
var
  CanvasState: TCanvasSaveState;
begin
  CanvasState := Canvas.Save;
  try
    // Flat模式下先填充与父控件一致的背景，避免闪烁
    if Flat then
    begin
      Canvas.Brush.Color := Parent.Color;
      Canvas.FillRect(ClientRect);
    end;
    // 执行原有绘制逻辑
    inherited Paint;
  finally
    Canvas.Restore(CanvasState);
  end;
end;

使用这个自定义控件替代原生TSpeedButton，能从绘制根源减少闪烁。

方案3：用双缓冲Panel包裹按钮

如果不想修改控件代码，可以给每个TSpeedButton套一个小型TPanel：

• 创建一个小TPanel，设置Align = alClient、DoubleBuffered = True、BorderStyle = bsNone
• 将TSpeedButton放在这个小Panel内，设置Align = alClient
• 把这个组合控件放到原面板中

小Panel的双缓冲会处理按钮的绘制缓冲，从而消除闪烁。

补充：问题复现DFM代码 #

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 337
  ClientWidth = 635
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object Panel1: TPanel
    Left = 0
    Top = 0
    Width = 635
    Height = 337
    Align = alClient
    Caption = 'Panel1'
    TabOrder = 0
    object SpeedButton1: TSpeedButton
      Left = 64
      Top = 56
      Width = 32
      Height = 32
      Flat = True
      Glyph.Data = {
        360C0000424D360C000000000000360000002800000020000000200000000100
        180000000000000C000000000000000000000000000000000000FFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CED241C
        ED241CED241CED241CED241CED241CED241CED241CED241CED241CED241CED24
        1CED241CED241CED241CED241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDFFFF
        FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
        FFFFFFFFFFFFFFFFFFFFFF241CED241CED241CED241CED241CEDCC483FCC483F
        CC483FCC483FCC483FCC483FCC483F
      }
    end
  end
end

内容的提问来源于stack exchange，提问作者CodeX