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  • Your email address will not be published.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

  • QA teams don't have time to test everything yet they can't afford to ship buggy code. Learn how Coverity can help organizations shrink their testing cycles and reduce regression risk by focusing their manual and automated testing based on the impact of change.

  • On-demand Event Event Date: September 10, 2014 Modern mobile applications connect systems-of-engagement (mobile apps) with systems-of-record (traditional IT) to deliver new and innovative business value. But the lifecycle for development of mobile apps is also new and different. Emerging trends in mobile development call for faster delivery of incremental features, coupled with feedback from the users of the app "in the wild." This loop of continuous delivery and continuous feedback is how the best mobile …

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds