用Delphi实现自定义颜色对话框程序

在Delphi中，可以使用TColorDialog组件实现颜色选择对话框。如果想要自定义颜色选择对话框，可以继承TColorDialog并重写其中的一些方法。

下面是一个简单的示例代码，演示如何实现自定义颜色选择对话框：

unit CustomColorDialog;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls;

type
  TCustomColorDialog = class(TColorDialog)
  private
    FCustomColors: array[0..15] of TColor;
  protected
    procedure DoShow; override;
    procedure PaintRect(Canvas: TCanvas; Rect: TRect; Color: TColor); virtual;
  public
    constructor Create(AOwner: TComponent); override;
  published
    property CustomColors: array[0..15] of TColor read FCustomColors write FCustomColors;
  end;

procedure Register;

implementation

{$R *.dfm}

constructor TCustomColorDialog.Create(AOwner: TComponent);
begin
  inherited;
  FCustomColors[0] := clBlack;
  FCustomColors[1] := clMaroon;
  FCustomColors[2] := clGreen;
  FCustomColors[3] := clOlive;
  FCustomColors[4] := clNavy;
  FCustomColors[5] := clPurple;
  FCustomColors[6] := clTeal;
  FCustomColors[7] := clGray;
  FCustomColors[8] := clSilver;
  FCustomColors[9] := clRed;
  FCustomColors[10] := clLime;
  FCustomColors[11] := clYellow;
  FCustomColors[12] := clBlue;
  FCustomColors[13] := clFuchsia;
  FCustomColors[14] := clAqua;
  FCustomColors[15] := clWhite;
end;

procedure TCustomColorDialog.DoShow;
var
  I: Integer;
  BtnRect, ColorRect: TRect;
  BtnWidth, BtnHeight, ColorWidth, ColorHeight: Integer;
  BtnTop, ColorTop, ColorLeft: Integer;
  BtnCaption: string;
  BtnFont: TFont;
  BtnColor: TColor;
  Canvas: TCanvas;
begin
  inherited;
  Canvas := TCanvas.Create;
  try
    Canvas.Handle := GetDC(Handle);
    BtnWidth := 50;
    BtnHeight := 20;
    ColorWidth := 15;
    ColorHeight := 15;
    BtnTop := ClientHeight - BtnHeight - 10;
    ColorTop := 10;
    ColorLeft := ClientWidth - 20 - (4 * ColorWidth);
    BtnFont := TFont.Create;
    try
      BtnFont.Assign(Font);
      BtnFont.Style := [fsBold];
      for I := 0 to 3 do
      begin
        BtnRect := Rect(20 + (I * BtnWidth), BtnTop, 20 + ((I + 1) * BtnWidth), BtnTop + BtnHeight);
        BtnColor := CustomColors[I];
        PaintRect(Canvas, BtnRect, BtnColor);
        BtnCaption := 'Color ' + IntToStr(I + 1);
        Canvas.Font := BtnFont;
        Canvas.Brush.Style := bsClear;
        DrawText(Canvas.Handle, PChar(BtnCaption), -1, BtnRect, DT_SINGLELINE or DT_CENTER or DT_VCENTER);
        for J := 0 to 3 do
        begin
          ColorRect := Rect(ColorLeft + (J * ColorWidth), ColorTop + (I * ColorHeight), ColorLeft + ((J + 1) * ColorWidth), ColorTop + ((I + 1) * ColorHeight));
          PaintRect(Canvas, ColorRect, CustomColors[(I * 4) + J]);
        end;
      end;
    finally
      BtnFont.Free;
    end;
  finally
    ReleaseDC(Handle, Canvas.Handle);
    Canvas.Free;
  end;
end;

procedure TCustomColorDialog.PaintRect(Canvas: TCanvas; Rect: TRect; Color: TColor);
begin
  Canvas.Brush.Color := Color;
  Canvas.Pen.Color := Color;
  Canvas.Rectangle(Rect);
end;

procedure Register;
begin
  RegisterComponents('Samples', [TCustomColorDialog]);
end;

end.

以上代码中，我们创建了一个名为TCustomColorDialog的自定义颜色选择对话框。在DoShow方法中，我们使用TCanvas绘制了自定义颜色区域和按钮区域。在PaintRect方法中，我们绘制了矩形，并填充了指定的颜色。

要使用自定义颜色选择对话框，只需将TCustomColorDialog组件放置在窗体中，并将其Execute方法调用即可：CustomColorDialog1.Execute。

希望这个示例对您有所帮助！