National Instruments IMAQTM Benutzerhandbuch

© National Instruments Corporation

Hold down <Shift> when drawing an ROI if you want to constrain the ROI 
to the horizontal, vertical, or diagonal axes, when possible. Use the 
selection tool to position an ROI by its control points or vertices. ROIs are 
context sensitive, meaning that the cursor actions differ depending on the 
ROI with which you interact. For example, if you move the cursor over the 
side of a rectangle, the cursor changes to indicate that you can click and 
drag the side to resize the rectangle. If you want to draw more than one ROI 
in a window, hold down <Ctrl> while drawing additional ROIs. You also 
can use 

CWIMAQViewer.MaxContours

 to set the maximum number of 

contours the viewer can have in its ROI. 

In the status bar of the viewer, you can display tool information about the 
characteristics of ROIs you draw, as shown in Figure 3-2. Check the Show 
Tool Info check box on the Status Bar property page during design time, 
or set the 

CWIMAQViewer.ShowToolInfo

 property to 

True

 during run 

time to display tool information. You also can show or hide the tool 
information from the right-click menu.

Polygon

Draw a polygon in the image.

Action: Click to place a new vertex and 
double-click to complete the ROI element.

Freeline

Draw a freehand line in the image. 

Action: Click the initial position, drag to the 
appropriate shape and release the mouse button to 
complete the shape.

Free Region

Draw a freehand region in the image.

Action: Click the initial position, drag to the 
appropriate shape and release the mouse button to 
complete the shape.

Zoom

Zoom in or zoom out in an image.

Action: Click the image to zoom in. Hold down 
<Shift> and click to zoom out.

Pan

Pan around an image.

Action: Click an initial position, drag to the 
appropriate position, and release the mouse button 
to complete the pan.

Table 3-1.  Tools Palette Functions (Continued)