[Biojava-l] leader and trailer in Renderers

[David Huen]

On Mon, 4 Mar 2002, Matthew Pocock wrote:

> The leading and trailing space is requested per renderer. This is 
> because some glyphs (e.g. numbers) are scale-invarient and will be 
> clipped off if the rendering is clipped exactly. I think the container 
> of the sequence renderers loops over these and finds the maximum one. 
> Then, it individualy translates each sequence renderer so that their 
> sequence-based co-ordinates line up, but they are guaranteed a minimum 
> of leader and trailer padding. Does that help?
> 
In which case I think LayeredRenderer is buggy.  It has its own
getMinimumLeader/Trailer methods that compute to the value required
to fulfil the requirements of all renderers but in the draw loop, it
actually calls that of the renderer being invoked at that time:-

            SequenceRenderer sRend = (SequenceRenderer) i.next();
            int dir = src.getDirection();
            double depth = sRend.getDepth(src);

            // Sequence range should be inclusive of the min/max
            // coordinates for sequenceToGraphics() so we use
            // src.getRange().getMax() + 1
            double minP = src.sequenceToGraphics(src.getRange().getMin())
-
                sRend.getMinimumLeader(src);
            double maxP = src.sequenceToGraphics(src.getRange().getMax() +
1) +
                sRend.getMinimumTrailer(src);

It is wrong, isn't it?  There also appears to be a bug in the getDepth
method which fails to account for overdrawing. The latter is almost
certainly caused by me from a long time ago.

If we are agreed the above is wrong, I'll patch it and upload.

Sorry for the bother - I'm not think very clearly just now and I don't
want to break the thing just before a bootcamp.

Regards,
David Huen