//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
Graphics::TBitmap* Bitmap = Image1->Picture->Bitmap;
//声明RGB色盘数组
RGBQUAD rgbQ[256];
memset(rgbQ, 0, 256);
//取得Image1的色盘，并逐一修改颜色
if (::GetDIBColorTable(Bitmap->Canvas->Handle, 0, 256, rgbQ))
{
for (int index = 0; index < 256; index++)
{
// floor函数 #include <math>
//取出色盘中每一RGB加以平均，再提升亮度
//此方法并非惟一取值方式
int gray = floor((rgbQ[index].rgbBlue +
rgbQ[index].rgbGreen +
rgbQ[index].rgbRed)/3*1.05);
//限制颜色范围
if(gray <= 0) gray = 0;
if(gray >= 255) gray = 255;
//当RGB同为一值时，即显示为灰阶
rgbQ[index].rgbBlue = (byte)gray;
rgbQ[index].rgbGreen = (byte)gray;
rgbQ[index].rgbRed = (byte)gray;
}
//将设好之色盘，指派给Image1使用
::SetDIBColorTable(Bitmap->Canvas->Handle, 0, 256, rgbQ);
//重绘Image1
Image1->Repaint();
}
}
//---------------------------------------------------------------------------
