如何快速清空画布

[yiyanghuadan]

有问题如下：
在一个TPaintBox上做图（主要是画曲线），其下有图象背景，因为要进调整曲线的整，所以要快速地清除其上的曲线，但又不能影响图象背景
请问如何快速清除呀

不要告诉我
Graphics::TBitmap temp=new Graphics::TBitmap;
temp->Height=xxx;
temp->Width=yyy;
PaintBox1->Draw(0,0,temp);
我要的是快速

[Libran]

PaintBox1->Canvas->FillRect(PaintBox1->ClientRect);

[pzoon]

PaintBox1->Canvas->FillRect(PaintBox1->ClientRect

[tjzzx888]

to jianlinlong(楚 潇)
PaintBox1->Canvas->Refresh();不行吧，我也不知道
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[jianlinlong]

PaintBox1->Canvas->Refresh();

[meCAD]

用PaintBox1->Canvas->Rectangle(0,0,100,100);
矩形覆盖掉原来的画面
或者PaintBox1->Canvas->FillRect(PaintBox1->ClientRect);

[liux330]

PaintBox1->Canvas->Brush->Bitmap = NULL;

[dahuzizyd]

这个程序主要是利用TList对操作前的图象进行保存，进行撤消操作时再从TList中调用，你试试吧，肯定是可行的，不过可能还要在调试一下。
TList *myList = new TList（）; //声明一个TList类

void __fastcall TForm1::Button2Click(TObject *Sender)
{ //画图
Image1->Picture->Bitmap->Canvas->Brush->Color = clBlue;
Image1->Picture->Bitmap->Canvas->Rectangle(50,50,200,200);
Graphics::TBitmap * bitmap1 = new Graphics::TBitmap();
bitmap1 -> Assign ( Image1 -> Picture -> Bitmap);
myList -> Add( bitmap1);
i = i + 1;

void __fastcall TForm1::Button3Click(TObject *Sender)
{ //撤消操作
//Image1->Picture->Bitmap->Handle= myList->Items[0] ;
//int i ;
//i = myList->Count-2 ;
Image1->Picture->Bitmap-> Assign ( (Graphics::TBitmap*)myList -> Items[i-2] );
i = i - 1;
//if ( (Graphics::TBitmap*)myList -> Items[i+1] )
//delete ((Graphics::TBitmap*)myList -> Items[i+1] );
}
void __fastcall TForm1::FormCreate(TObject *Sender)
{
Graphics::TBitmap * bitmap1 = new Graphics::TBitmap();
bitmap1 -> Assign ( Image1 -> Picture -> Bitmap);
myList -> Add( bitmap1);
i = i + 1;

}

[CoolSoftBird]

PaintBox->Canvas->Refresh()不行