Using the Magnifying Glass

LEADTOOLS provides a "magnifying glass" for the LBitmapWindow class. This magnifying glass provides a means of "zooming in" on the image loaded into an LBitmapWindow object.

Note that in the Document/Medical toolkits LEADTOOLS also provides a "Zoom View" that can be attached to a window handle.

Use the "Zoom View" if you want to:

$image\sqrblit.gif$ display one or more zoomed views for a single displayed image

$image\sqrblit.gif$ display an annotation in addition to the zoomed view

$image\sqrblit.gif$ display callout lines

For more information about the Zoom View, refer to Using the Zoom View.

Use the "Magnifying Glass" if you want to:

$image\sqrblit.gif$ control the painting options for the zoomed display.

$image\sqrblit.gif$ set the contrast, gamma and intensity for the zoomed area.

The magnifying glass options and the zoomed display options are set using a MAGGLASSOPTIONS structure. To use the magnifying glass, call the LBitmapWindow::GetMagGlassOptions function to get the current magnifying glass options. Next call the LBitmapWindow::SetMagGlassOptions function to set any new magnifying glass options to be used. Then call LBitmapWindow::SetToolType to set the tool type to TOOL_MAGGLASS. As the magnifying glass is moved over an image, the zoomed - in view is also displayed. To determine whether a class object has a magnifying glass attached to it, call the LBitmapWindow::IsToolTypeMagGlass function. The following can be set in a MAGGLASSOPTIONS structure:

$image\sqrblit.gif$ size of the magnifying glass

$image\sqrblit.gif$ shape of the magnifying glass

$image\sqrblit.gif$ magnifying glass border (color, thickness, appearance)

$image\sqrblit.gif$ magnification level

$image\sqrblit.gif$ paint characteristics

$image\sqrblit.gif$ section of the pixel on which to center the zoomed image

$image\sqrblit.gif$ color masks

When the magnifying glass is no longer needed, just change the tool type using LBitmapWindow::SetToolType.

LEADTOOLS provides two defined shapes for the Magnifying Glass: Rectangle and Ellipse. The LBitmapWindow::UpdateMagGlassShape function lets you update the shape of the magnifying glass to one of the previously listed shapes, or to a custom shape.