SYSTEM BASICS
Selectingand Displaying Windows–SerialPort Control
10 SuperView3000 User Manual May9, 2002
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Example––define thed estination rectangle in Figure 4. That
is,place the top left corner of window1 at (300, 700) of the
display’s raster, and use a window 600 pixels wide and 250
lines high:
>wdr 1 300 700 600 250
TheSuperView provides query commands that let you get the current value(s)
of most system parameters.
Example––querythe SuperView on the current WDR values
forwindow 1:
>wdr 1
Thesystem responds by listing the frame buffer coordinate
values:
>300 700 600 250
.
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ASPECT RATIO Anydesired rectangular portion of an input image can be displayed in the
correspondingwindow. Also, the window itself can be set to have any
rectangularshape and be any desired size on the monitor, up to the full size of
theoutput raster. The size and shape of the source rectangle are independent of
thedestination rectangle’s size and shape. This has important consequences.
Letus supposethat you defined aninput’s source and destination rectangles so
thatthe central 320pixels by 240 lines of a video source image were mapped
intoa 6 40x480 window. In this case, the destination rectangle is larger than the
sourcerectangle, but has the same shape and the same width-to-height aspect
ratio (4:3). Thus, the original input image is scaled equally in both dimensions
for display on the monitor.
Varyingthe destination rectangle’ssize but preserving its aspect ratio makes the
displayedimage larger or smaller. As long as its proportions correspond to
thoseof thesource rectangle, the displayed image will resemble the input
image.If you independently vary the shape of either the source or destination
rectangle,so that their aspect ratios are no longer the same, your displayed
picturewill appear stretched or squeezed compared to the original image.
Figure4 shows how the image is stretched by using a destination rectangle with
a different,more elongated shape than that of the source rectangle.
POSITIONING
.
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AND CLIPPING
A window canb e positioned anywhere on the output raster.If the window’s
destinationrectangle is defined so that a po rtiono f the window is offthe screen,
that portion of the windowed image is clipped (until it is moved back into
view). This “image clipping” is illustrated in Figure 5. The window is
positioned by specifying the screen coordinates of itstop left corner. Negative
coordinate values clip from the left and top edges of the window.