//---------------------------------------------------------------------------
#include <vcl.h>
#include <Vcl.Imaging.pngimage.hpp>
#pragma hdrstop

#include "BackgroundForm.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)


TPngImage *u_pImgCellTile = NULL;

__fastcall TBackgroundForm::TBackgroundForm(TComponent* AOwner)
: TForm(AOwner)
{
	m_yLeftSide = -1;

	if( !u_pImgCellTile ){
		u_pImgCellTile = new TPngImage();
		u_pImgCellTile->LoadFromResourceName(int(HInstance), L"PngBackTile");
	}
}
//---------------------------------------------------------------------------

__fastcall TBackgroundForm::~TBackgroundForm()
{
	if( u_pImgCellTile ){
		delete u_pImgCellTile;
		u_pImgCellTile = NULL;
	}
}
//---------------------------------------------------------------------------

void __fastcall TBackgroundForm::WMEraseBkgnd(Winapi::Messages::TWMEraseBkgnd &Message)
{
	if( u_pImgCellTile ){
        TCanvas* tempCanvas = new TCanvas;
        tempCanvas->Handle = Message.DC;

		int nBottom = ClientHeight - u_pImgCellTile->Height;
		//绘制面板上下部分
		for (int i=0; i<2; i++){
			int y = i==0 ? 0 : nBottom;

			for (int x=0; x<ClientWidth; x+=u_pImgCellTile->Width){
				tempCanvas->Draw( x, y, u_pImgCellTile );
			}
		}

		if( m_yLeftSide>=0 ){  //ComposeForm列表框最小化时须填充左侧
			for(int y=m_yLeftSide; y<nBottom; y+=u_pImgCellTile->Height ){
                tempCanvas->Draw( 0, y, u_pImgCellTile );
			}
		}

        delete tempCanvas;

        Message.Result = true;
	}
	else{
		DefaultHandler( &Message );
	}
}
//---------------------------------------------------------------------------