cast to integer in image coordinates

[patrickmachado@…]

The output-svg module casts point coordinates to integers, when outputing
results in full resolution (and conversion to image coordinates).

This is a drawback because resolution is lost (e.g. when you want to zoom the
map later). Furthermore, the lines are poorly antialiased this way.

I looked into the code and it seems that the right way is already there, but
commented. Is there any reason for that?

Here follows the relevant code:


/* full resolution, pixel output */
    if (bFullRes && !bUseGeoCoord)
    {
        if(shape->type == MS_SHAPE_LINE || shape->type == MS_SHAPE_POLYGON) 
        { 
            for(i=0; i<shape->numlines; i++) 
            {
                for(j=0; j < shape->line[i].numpoints; j++ ) 
                {
                    /*
                    shape->line[i].point[j].x = 
                      (shape->line[i].point[j].x - extent.minx)/cellsize;
                    shape->line[i].point[j].y = 
                      (extent.maxy - shape->line[i].point[j].y)/cellsize;
                    
                    */
                    shape->line[i].point[j].x =
MS_MAP2IMAGE_X(shape->line[i].point[j].x,
                                                               extent.minx,
cellsize);
                    shape->line[i].point[j].y = MS_MAP2IMAGE_Y(
shape->line[i].point[j].y,
                                                                extent.maxy,
                                                                cellsize);
                                                                
                    
                }
            }      
            return;
        }
    }

[hopfgartner]

There is no cure for the symptone in this part of the mapserver code. I tried to compile mapserver, SVN as of today, 2008-09-15 with both variants, the original one and the one commented out, and there is no significant visual difference, files attached, look at them at 500%. Anyway, I did not try to find where the correct fix should belong, maybe someone knows, where the path coordinates are aligned with the grid.

[hopfgartner]

Fix

[assefa]

reopening to apply the patch

[assefa]

checking the patch now.

[assefa]

Attaching a patch with changes that allow to fulfill the FULL_RESOLUTION settings and keeps the old behavior if that metadata is not set. It is applied both on lines and polygons.

Peter, if it is possible for you to quickly test the patch, that would be great. I can then commit.

The only thing that I thing is missing is maybe a par mater allowing the user to specify the resolution (numbers after .). For now it is set to 2.

[assefa]

patch committed in r7913