Scrolling size on zooming

[Anu_Bala]

Hi, I got one CZoomView sample file form code project.Actually i want zoom fucntion in my applcaiton for every view.In tht,initially when i set scrollposition,extra window is appearing. For example,in OnDraw(),i set background of window as black

CRect mClientArea;
GetClientRect(&mClientArea);
pDC->FillRect(&mClientArea,&CBrush(RGB(0,0,0)));

I set scroolsize as

m_layout.cx = GetSystemMetrics( SM_CXSCREEN );
m_layout.cy = GetSystemMetrics( SM_CYSCREEN );
m_page.cx = m_layout.cx/2; m_page.cy = m_layout.cy/2;
m_line.cx = m_layout.cx/50; m_line.cy = m_layout.cy/50;
SetScrollSizes(MM_TEXT, m_layout, m_page, m_line);

What happended is after execution,when i scroll the horizonatal or vertical scrolls,the window is scrolling more than actual window rect. More white screen is appearing apart for black background.How can i avoid that? Because while zooming,if user move the scrolls,then extra empty window will appear.i want to avoid that.

Anu

[kylur]

Anu, Try this: // header file: "MyScrollView.h"

#pragma once

class CDoc;
class CMyScrollView : public CScrollView
{
DECLARE_DYNCREATE(CMyScrollView)
DECLARE_MESSAGE_MAP()

public:
CMyScrollView();
virtual ~CMyScrollView();

CDoc\* GetDocument();

protected:
virtual void OnDraw(CDC* pDC);
virtual void OnInitialUpdate();

private:
int Height;
int Width;
CBitmap* Bitmap;
CDC* MemDC;
};

// implementation file: "MyScrollView.cpp"

#include "stdafx.h"
#include "MyScrollView.h"

IMPLEMENT_DYNCREATE(CMyScrollView, CScrollView)
BEGIN_MESSAGE_MAP(CMyScrollView, CScrollView)
END_MESSAGE_MAP()

CMyScrollView::CMyScrollView() :
Bitmap(new CBitmap), Width(1000), Height(200), MemDC(new CDC)
{
MemDC->CreateCompatibleDC(NULL);
}

CMyScrollView::~CMyScrollView()
{
delete Bitmap;
delete MemDC;
}

CDoc* CMyScrollView::GetDocument()
{ return (CDoc*)m_pDocument; }

void CMyScrollView::OnInitialUpdate()
{
CScrollView::OnInitialUpdate();

GetParentFrame()->SetWindowText("CMyScrollView");

CClientDC dc(this);
Bitmap->CreateCompatibleBitmap(&dc, Width, Height);
Bitmap->SetBitmapDimension(Width, Height);

CBitmap\* OldBitmap = MemDC->SelectObject(Bitmap);

MemDC->PatBlt(0, 0, Width, Height, BLACKNESS);
CPen WhitePen(PS\_SOLID, 1, RGB(255,255,255));
CPen\* 	OldPen = MemDC->SelectObject(&WhitePen);
MemDC->MoveTo(0, 0);				// ie top left
MemDC->LineTo(Width, Height);		// ie bottom right
MemDC->MoveTo(Width, 0);			// ie top right
MemDC->LineTo(0, Height);			// ie bottom left
MemDC->SelectObject(OldPen);

CPen RedPen(PS\_SOLID, 1, RGB(255,0,0));
OldPen = MemDC->SelectObject(&RedPen);
MemDC->Rectangle(0,0,10,10);		// red rect in top left
MemDC->SelectObject(OldPen);

CPen GreenPen(PS\_SOLID, 1, RGB(0,255,0));
OldPen = MemDC->SelectObject(&GreenPen);
MemDC->Ellipse(Width-20, Height-20, Width, Height);	// green circle bottom right
MemDC->SelectObject(OldPen);

CRect Rect(0,Height-20,20,Height);
CBrush Brush(RGB(0,0,255));
MemDC->FillRect(Rect, &Brush);		// blue rect in bottom left

MemDC->SelectObject(OldBitmap);

SetScrollSizes(MM\_TEXT, CSize(Width, Height));
ResizeParentToFit(TRUE);

}

void CMyScrollView::OnDraw(CDC* pDC) // works!
{
if (Bitmap)
{
pDC->SetStretchBltMode( COLORONCOLOR );

	CBitmap\* OldBitmap = MemDC->SelectObject(Bitmap);

	pDC->BitBlt( // l, t, w, h
		0, 0, Width, Height,