Using the Zoom View

LEADTOOLS provides a "zoomed view" that can be attached to a Bitmap Window. This Zoom View provides a means of "zooming in" on the image loaded into the window to which it is attached. This is similar to having multiple Magnifying Glasses on the same source image.

Note that LEADTOOLS also provides a "magnifying glass" that can be attached to a window handle. Use the "Magnifying Glass" if you want to:

• control the painting options for the zoomed display.

• set the contrast, gamma and intensity for the zoomed area.

For more information about the magnifying glass, refer to Using the Magnifying Glass.

Use the "Zoom View" if you want to:

• display one or more zoomed views for a single displayed image.

• display an annotation in addition to the zoomed view.

• display callout lines.

To attach the zoomed view to a Bitmap window, call the LBitmapWindow::AddZoomView function. To determine whether a window has a zoomed view attached to it, call the LBitmapWindow::HasZoomView function. As the source rectangle is moved over an image, the zoomed - in view also changes.

The following can be set using the ZOOMVIEWPROPS structure:

• the rectangle describing the source area of the image to be zoomed.

• the rectangle describing the location of the zoomed view.

• the zoom factor.

• whether the zoomed view should be the size of the rectangle describing the location of the zoomed view, or whether to display the source rectangle magnified by the specified zoom factor.

• the border style for the zoomed view, along with border color and pen style.

• the border style for the source rectangle, along with border color and pen style.

• whether callout lines will be used, along with color and pen style.

• the annotation object to be displayed.

Use the LBitmapWindow::GetZoomViewProps function to obtain the properties for the specified zoom view.

To change the current options for the specified Zoom View, change the values in the structure pointed to by pZoomViewProps and pass a pointer to the updated structure to the LBitmapWindow::UpdateZoomView function.

To update the Zoom View with a new destination rectangle, call the LBitmapWindow::UpdateZoomView function.

The LBitmapWindow::AddZoomView function lets you set all of the properties of a zoomed view through the ZOOMVIEWPROPS structure.

The LBitmapWindow::EnableHiliteZoomView enables or disables "highlighting" of the zoom view source area in the underlying image of the LBitmapWindow when zoom views are displaying.

The LBitmapWindow::IsHiliteZoomViewEnabled determines whether the underlying image for the LEADRasterView is "highlighted" in the source area when a zoom view is enabled

LEADTOOLS provides several different shapes for the zoomed view, including a rectangle, a rounded rectangle and a shape that looks like a piece of paper that has been torn from a larger sheet.

When the zoomed view is no longer needed, call the LBitmapWindow::DestroyZoomView function to stop the Zoom View procedure and to detach it from the window handle.