Graphics Subroutine: Limits graphics output to part of the screen.
CALL SETCLIPRGN (x1,y1,x2,y2)
x1, y1 |
(Input) INTEGER(2). Physical coordinates for upper-left corner of clipping region. |
x2, y2 |
(Input) INTEGER(2). Physical coordinates for lower-right corner of clipping region. |
The SETCLIPRGN function limits the display of subsequent graphics output and font text output to that which fits within a designated area of the screen (the "clipping region"). The physical coordinates (x1, y1) and (x2, y2) are the upper-left and lower-right corners of the rectangle that defines the clipping region. The SETCLIPRGN function does not change the viewport-coordinate system; it merely masks graphics output to the screen.
SETCLIPRGN affects graphics and font text output only, such as OUTGTEXT. To mask the screen for text output using OUTTEXT, use SETTEXTWINDOW.
例
This program draws an ellipse lying partly within a clipping region, as shown below.
! Build as QuickWin or Standard Graphics ap.
USE IFQWIN
INTEGER(2) status, x1, y1, x2, y2
INTEGER(4) oldcolor
x1 = 10; y1 = 50
x2 = 170; y2 = 150
! Draw full ellipse in white
status = ELLIPSE($GBORDER, x1, y1, x2, y2)
oldcolor = SETCOLORRGB(Z'FF0000') !blue
WRITE(*,*) "Hit enter"
READ(*,*)
CALL CLEARSCREEN($GCLEARSCREEN) ! clear screen
CALL SETCLIPRGN( INT2(0), INT2(0), &
INT2(150), INT2(125))
! only part of ellipse inside clip region drawn now
status = ELLIPSE($GBORDER, x1, y1, x2, y2)
END
The following shows the output of this program.
