如何获取图片中第一个像素的颜色值? 回复 "格兰特" 的问题

问题来源: http://www.cnblogs.com/del/archive/2009/03/15/1410030.html#1477217

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

const BmpPath = 'C:\Temp\Test.bmp'; {测试用图片}

{使用 Canvas.Pixels 属性}
procedure TForm1.Button1Click(Sender: TObject);
var
  bit: TBitmap;
  clr: TColor;
begin
  bit := TBitmap.Create;
  bit.LoadFromFile(BmpPath);      {载入图片}
  clr := bit.Canvas.Pixels[0, 0]; {获取第一像素的颜色值}
  ShowMessageFmt('$%.6x', [clr]); {显示为十六进制字符串看看}
  //Self.Color := clr;            {可用窗体呈现一下}
  bit.Free;
end;

{使用 API 函数 GetPixel}
procedure TForm1.Button2Click(Sender: TObject);
var
  bit: TBitmap;
  clr: TColor;
begin
  bit := TBitmap.Create;
  bit.LoadFromFile(BmpPath);               {载入图片}
  clr := GetPixel(bit.Canvas.Handle, 0, 0);{获取第一像素的颜色值}
  ShowMessageFmt('$%.6x', [clr]);          {显示为十六进制字符串看看}
  //Self.Color := clr;                     {可用窗体呈现一下}
  bit.Free;
end;

end.