Magnifying Glass - demonstrates different ways to obtain or create proper DC and use BitBlt - StretchBlt functions

Environment:VC5/VC6

Generally the sample demonstrates different ways to obtain or create proper DC and use BitBlt - StretchBlt functions.

It is another ZoomIn demo application created with doc-view architecture. CView derived class experienced minimum changes from AppWizard generated one.

CImageWnd window covers CView derived class window. CImageWnd contains a copy (mirror) of CView derived class window bitmap to draw. CImageWnd window becomes transparent when magnifying glass is inactive and draws a "lens" over the bitmap when active. The "lens" is a small zoom window. Magnifying Glass doesn't depend on a view contents. It is easy to modify CMgnView::OnDraw or CMgnView::OnEraseBkgnd and Magnifying Glass still will work with another contents.

To activate or deactivate magnifying glass - press button on a toolbar.

To magnify a portion of a view - activate magnifying glass, press left mouse button and move "lens" around a view.

To change magnifying glass size, shape or zoom - activate magnifying and click a view with right mouse button. It is possible to create several views just use file - new command. Note that for each view magnify glass keeps its own properties.

It is easy enough to make a "lens" astigmatic (cylinder) or add another "optical effects".

I couldn't remove some "optical side effects". When magnifying glass is slowly moved from outside a frame inside it over a border you see a "diffraction grid".

Download source - 27 Kb



Comments

  • There are no comments yet. Be the first to comment!

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • IBM Worklight is a mobile application development platform that lets you extend your business to mobile devices. It is designed to provide an open, comprehensive platform to build, run and manage HTML5, hybrid and native mobile apps.

  • In support of their business continuity and disaster recovery plans, many midsized companies endeavor to avoid putting all their eggs in one basket. Understanding the critical role of last-mile connectivity and always available Internet access for their enterprises, savvy firms utilize redundant connections from multiple service providers. Despite the good intentions, their Internet connectivity risk may still be in a single basket. That is because internet service providers (ISPs) and competitive local …

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds