Doug,
I am beginning to implement a basic visualizer for finite element models and
meshes in Java3D. My users would like to see an enumeration of mesh
entities, i.e., elements/faces/edges/vertices, etc. Therefore, I have the
need for displaying large quantities of labels.
These labels should always stay the same size, and be oriented with the
screen, but must also rotate/translate to keep on top of their associated
mesh object as the user moves the model. For these labels, raster text
sounds like a good solution. I am guessing this many labels would have big
space and time issues. Shared memory for raster fonts would help out.
--Kevin Copps
> -----Original Message-----
> From: Doug Gehringer [mailto:[EMAIL PROTECTED]]
> Sent: Monday, July 16, 2001 6:32 PM
> To: [EMAIL PROTECTED]
> Subject: Re: [JAVA3D] Question on Raster Labels
>
>
>
> Here is an implementation of Raster labels (attached). It is
> basically Text2D
> modified to used a Raster instead of a texture mapped polygon.
>
> There are currently no plans to add raster text to the Java
> 3D utilities, but a
> raster text utility may be considered if there is interest.
> I'd like to hear
> your input.
>
> Here is a comparision of raster text vs Text2D and Text3D:
>
> Appearance:
> Text2D: Raster text on a texture mapped polygon.
> Raster text, but
> with sometimes blurry due to scaling of the
> texture mapped
> image.
> Text3D: Outline of font is converted to geometry.
> Excellent appearance
> for large sizes. Can be blocky for small
> sizes when characters
> are only a couple pixels wide.
> Raster Text: Excellent appearance since it uses raster
> fonts only at their
> indended size.
>
> Size/orientation:
> Text2D/Text3D: Full 3D orientation. Rotates/scales with
> transformations and
> viewing. Can be made to align with screen
> using OrientedShape3D
> (must edit Text2D to do this). With 1.3 can
> be made size
> invariant using the new constant scaling on
> OrientedShape3D
> Raster text: Always the same size and aligned with the
> screen, so only useful
> for specific situations.
>
> Memory Usage/Limitations:
> Text2D: No sharing between primitives, each uses its
> own memory even
> if they share characters. If texture is too
> wide it won't
> display on some devices.
> Text3D: Characters are defined in a Font3D so that
> the memory for
> each character is shared between different
> instances of each
> character.
> Raster text: Label3D is like Text2D-- each primitive uses
> it's own copy of
> the character definitions. With J3D 1.3
> raster text could be
> implemented using a font mechanism like
> Text3D. Also, Rasters
> are sometimes slow on some PC cards.
>
> Please send your comments to [EMAIL PROTECTED] and I'll
> post a summary.
> Specifically: Do you have a need for raster text? Why?
> Would you need the
> shared memory of a font-based implementation (that is, would
> you use a lot of
> labels)?
>
> BTW, Label3D gets the font metrics with:
>
> Toolkit toolkit = Toolkit.getDefaultToolkit();
> metrics = toolkit.getFontMetrics(font);
>
> It caches the font metrics on the class to speed up creation
> of the labels.
>
> > From: R Vegan <[EMAIL PROTECTED]>
> > An alternative way is to get the FontMetrics object from
> > the graphics handle of the BufferedImage object. This
> > seems to work fine.
>
> This is probably a better way, although Text2D uses presently
> uses the Toolkit
> mechanism.
>
> Thanks
>
> Doug Gehringer
> Sun Microsystems
>
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