Q120396

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Q120396: PRB: Image Functions Fail with Image Outside of Viewport

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Article: Q120396
Product(s): Microsoft Fortran Compiler
Version(s): 1.0a
Operating System(s): 
Keyword(s): 
Last Modified: 30-AUG-2001

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The information in this article applies to:

- Microsoft FORTRAN PowerStation for MS-DOS, version 1.0a 
-------------------------------------------------------------------------------

SYMPTOMS
========

The image functions SAVEIMAGE, SAVEIMAGE_W, LOADIMAGE, and LOADIMAGE_W fail when
the specified image falls outside the current viewport. After SAVEIMAGE fails,
calling GRSTATUS will return: $GRIMAGEREADERROR.

CAUSE
=====

Though not documented, this behavior is by design. The functions listed above
will fail when you attempt to place even part of an image outside the viewport.
Images are never clipped to the viewport.

RESOLUTION
==========

Do not attempt to place images outside of the current viewport. Either make the
viewport larger or work with partial (smaller) images.

STATUS
======

This behavior does occur with FORTRAN PowerStation 32.

MORE INFORMATION
================

To demonstrate the problem, compile and run the sample program. The only bitmap
file saved will be TEST.BMP, and the output will be:

  Saving full viewport returns:           0
  Saving outside viewport returns:         -1
  Saving outside viewport GRSTATUS: $GRIMAGEREADERROR

Sample Code
-----------

  C Compile options needed: none

        include 'fgraph.fi'
        include 'fgraph.fd'

        integer*2 i, ret(3)

        i = setvideomode($VRES16COLOR)
        call setviewport(10,10,20,20)
        ret(1) = saveimage("test.bmp",0,0,10,10)
        ret(2) = saveimage("test2.bmp",0,0,10,11)
        ret(3) = GRSTATUS()

        i = setvideomode($DEFAULTMODE)

        print *, "Saving full viewport returns:", ret(1)
        print *, "Saving outside viewport returns:", ret(2)
        if (ret(3) .eq. $GRIMAGEREADERROR)
       +    print *, "Saving outside viewport GRSTATUS: $GRIMAGEREADERROR"

        end

Additional query words: 1.00 1.00a

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Keywords          :  
Technology        : kbAudDeveloper kbFortranSearch kbZNotKeyword3 kbFORTRANPower100aDOS
Version           : :1.0a

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