Draws a grayscale bar on a frame containing an image.
BAR frame [keywords]
The BAR command displays a grayscale bar and labels. The bar is written to the image so an enhancement created with commands EU or EB appears on the bar. Because the labels are written as graphics, the EG command erases the labels but not the bar. The frame parameter specifies the frame to write the bar, and the GRA keyword specifies the frame to write the labels.
The POSITION keyword determines the location of the bar. If you do not use this keyword, the bar is drawn in a vertical orientation along the right side of the frame. If you use the POS=line ele short long format, line and ele define the TV line and element of the upper-left corner of the bar, and short and long define the dimensions of the bar. If you use ORIENT=VER, short is the horizontal length and long is the vertical length. If you use ORIENT=HOR, short is the vertical length and long is the horizontal length.
If the image was displayed with a stretch table (for example, using IMGDISP with the SU keyword), BAR's SU and RANGE keywords are ignored. If the image has an auxiliary block (for example, NEXRAD Level III radar images), the RANGE keyword is ignored and the LINT keyword is valid only if the image was displayed with a stretch table.
The following three rules determine the units of the labels.
This entry displays a vertical grayscale bar and graphics labels along the right side of the current frame.
BAR ORIENT=HOR LINT=15 LSIZE=6 COLOR=5
This entry displays a horizontal grayscale bar and graphics labels along the bottom of the current frame. The labels are drawn every 15 brightness levels along the bar in graphics color level 5 with a character height of six pixels.
This entry displays a grayscale bar that fills the cursor at its current location. The dimensions of the cursor determine the orientation of the bar and labels. If the cursor is square or is longer in the vertical direction than in the horizontal direction, the bar and labels are oriented vertically. If the cursor is longer in the horizontal direction than in the vertical direction, the bar and labels are oriented horizontally.
BAR POS=20 20 10 600 ORIENT=HOR SU=QVISRB RANGE=180 330 LINT=15
This entry displays a horizontal grayscale bar and graphics labels along the top of the current frame. The bar, which displays only values between 180 and 330, is 10 pixels high, 600 pixels long, and starts at TV line 20, element 20. The labels appear every 15 values along the bar in units matching the calibration units of the stretch table QVISRB.
BAR ANNOT=YES L 445 5 2 8
This entry displays a vertical grayscale bar and graphics in the default location (along the right side of the frame) and displays the memo field of the currently displayed image in graphics color level 2 with a character height of eight pixels beginning at TV line 445, element 5. If the image also has an INFO AUX block (like NEXRAD precipitation images), it is displayed below the memo field. The memo field can be listed by specifying FORM=ALL with the IMGLIST command.