BackErase example for C++ 4.0 and later

This example turns off repainting of the background, then zooms out to show the effect when repainting.

m_Lead1.SetBackErase(FALSE);
m_Lead1.SetAutoRepaint(FALSE);
m_Lead1.SetAutoScroll(FALSE);

// Calculate the values to zoom out by 10 percent and center the image.
m_Lead1.SetDstWidth(m_Lead1.GetDstWidth() * 0.9f);
m_Lead1.SetDstHeight(m_Lead1.GetDstHeight() * 0.9f);
m_Lead1.SetDstTop((m_Lead1.GetScaleHeight() - m_Lead1.GetDstHeight()) / 2);
m_Lead1.SetDstLeft((m_Lead1.GetScaleWidth() - m_Lead1.GetDstWidth()) / 2);

// Set the clipping area to the same as the destination rectangle
m_Lead1.SetDstClipWidth(m_Lead1.GetDstWidth());
m_Lead1.SetDstClipHeight(m_Lead1.GetDstHeight());
m_Lead1.SetDstClipTop(m_Lead1.GetDstTop());
m_Lead1.SetDstClipLeft(m_Lead1.GetDstLeft());

// Redisplay the image
m_Lead1.ForceRepaint();