Magnifying Cursor

• Download source files - 143 Kb
• Download demo project - 76.3 Kb

Introduction

This program generates a cursor that can magnify the portion on which it hovers.
I wrote this program to help myself make a small image editor. Using this code has made my program a very special one. Try it out.

Using the code

This program copies a part of the device context on to a bitmap. Stretches it and displays the bigger size.

This program uses three classes :-

• CDib: This class can load DIBs from file and from resource and also save DIB to disk.
• CBitmapDC: This class is derived from CDC. This class creates a bitmap from a given device context.
• CMaskedBitmap: This class can draw a bitmap without displaying one specific colour.

//
void CMagnifierView::OnMouseMove(UINT nFlags, CPoint point) 
{
    SetCursor(AfxGetApp()->LoadCursor(IDC_CURSOR1));
    CPoint p = GetScrollPosition();
    CClientDC pdc(this);
    CMemDC dc(&pdc);
    m_dib.Draw(&dc, CPoint(-p.x, -p.y), m_dib.GetDimensions());
    CRect rect1(CPoint(0, 0), m_dib.GetDimensions());
    CRect sel;
    CMaskedBitmap* bitm;
    CMaskedBitmap* bit;
    if(rect1.PtInRect(point))
    {
        CRgn rgn1, rgn2;
        sel = CRect(point.x-(20*1), point.y-(20*1), 
                     point.x+(20*1), point.y+(20*1));
        CBitmapDC bitmap(40*1, 40*1, &dc);
        CBitmapDC bitmap2(120*1, 120*1, &dc);
        rgn1.CreateEllipticRgn(0, 0, 120, 120);
        rgn2.CreateRectRgn(0, 0, 120, 120);
        rgn1.CombineRgn(&rgn2, &rgn1, RGN_DIFF);
        int y = sel.top, x = sel.left;
        for(int i = y; i<y+(40*1);i++)
        {
            for(int j = x; j<x+(40*1); j++)
            {
                COLORREF color = dc.GetPixel(j, i);
                int red = GetRValue(color);
                int green = GetGValue(color);
                int blue = GetBValue(color);
                bitmap.SetPixel(j-x, i-y, color);
            }
        }
        bitm = bitmap.Close();
        CDC dcMem;
        dcMem.CreateCompatibleDC(&dc);
        dcMem.SelectObject(bitm);
        bitmap2.StretchBlt(0, 0, 120*1, 120*1, &dcMem, 
                                     0, 0, 40, 40, SRCCOPY);
        bitmap2.FillRgn(&rgn1, &CBrush(RGB(255, 0, 254)));
        bit = bitmap2.Close();
        dc.SelectObject(&CPen(PS_SOLID, 1, RGB(0, 0, 0)));
        dc.SelectObject(&CBrush(NULL, RGB(0, 0, 0)));
        dc.Ellipse(point.x-(60*1)-1, point.y-(60*1)-1, 
                          point.x+(60*1), point.y+(60*1));
        bit->DrawTransparent(&dc, point.x-(60*1), 
                         point.y-(60*1), RGB(255, 0, 254));
        dc.MoveTo(point.x, point.y-(60*1)-1);
        dc.LineTo(point.x, point.y-(10*1)+1);
        dc.MoveTo(point.x, point.y+(10*1)-1);
        dc.LineTo(point.x, point.y+(60*1)+1);
        dc.MoveTo(point.x-(60*1)-1, point.y);
        dc.LineTo(point.x-(10*1)+1, point.y); 
        dc.MoveTo(point.x+(10*1)-1, point.y);
        dc.LineTo(point.x+(60*1)+1, point.y); 
    }
    CScrollView::OnMouseMove(nFlags, point);
}
//

Points of interest

I like programming applications with very cool looks. Using this cursor, the looks of the programs have been enhanced. Even game programming can use this type of cursor with a bit of enhancement.

History

• First update :- 27/01/2003 (Monday)