Conference bulova::decw_jan-89_to_nov-90

1208.0. "Strange filling seen" by TEKTRM::REITH (Jim Reith DTN 235-8459 HANNAH::REITH) Mon Jul 31 1989 18:37

I'm having a problem using XFillRectangle and XFillPolygon

My application scrolls a window around on a pseudo viewport and shows what is in 
the enclosed region. to do this I've been using clipping regions and drawing 
into the viewport. No problem.

Now think of it as moving the "paper" under a fixed window... The paper 
translates the objects while the clipping region stays fixed at 0,0 width,height

This generates calls to XFillRectangle with an x,y (int) that might be negative
and the fill color is splattered over the entire clipping region even though the
rectangle doesn't appear in the clipping region. Similar problems are seen with
XFillPolygon (the more interesting case)

x and y are stated as ints in the Getty's maroon X Windows book so they should
accept negative values right? The width and height are positive numbers as they
should be. Shouldn't the clipping region handle rectangles/polygons with negative
points. (as soon as the rectangle overlaps a clipping boundary it works just not
in the totally outside case)

Suggestions/insights?

VMS 5.1 on an 8 plane GPX microVax II

Sorry for the omission

I upgraded to the latest and greatest VMS 5.2 and still see the problem

What I ended up doing which causes more round trips than I had hoped was to
define the polygon as a region with XPolygonRegion and then use the clipping
rectangle with XRectInRegion and only draw if != RectangleOut. I still think
that the original form should have worked.