Re: layout patch - transform handling needed

From: Dom Lachowicz (domlachowicz@yahoo.com)
Date: Tue Feb 18 2003 - 12:22:52 EST

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    Hey Tomas,

    > I have been using the term 'transform' in a fairly
    > narrow sense, as a
    > reference to a 3x3 matrix that defines a
    > transformation that is
    > applied to user space before things are output to
    > the device (the PS
    > docs on Adobe website have quite a good intro to
    > this; PLRM.pdf,
    > section 4.3). This allows much more generic
    > transformations to be
    > handled than proportionate scaling, and it is the
    > way go.

    Yeah, we all know what transforms are. And, with a
    teensy bit of work, the PS class could support such
    things trivially. However, our GDK/FontConfig drawing
    functions are *incapable* of doing that.

    (In reality, we weren't and will probably never use
    the full power of transformation matrices - we're
    unlikely to skew, stretch, or rotate our output,
    translates happen via individual moveto commands. So
    Pat's use of transform == scale is correct for our
    current and future use cases. Using zoom factor as a
    virtual scale transform was the best we could come up
    with given the circumstances. Read on...).

    Now, it may well be quite easy to do this on win32,
    and is what you should do when porting win32 to the
    new layout units stuff. But font scaling was the best
    thing we could think of to solve the problem on unix
    until something better happens. Yes, we know *how* it
    should happen. Hell, we spent the better part of 2
    days trying to come up with a better solution than
    what we had, one that used the correct DPIs and
    possibly even transforms, but to no avail. Our heads
    are bruised from smacking them against the wall. Any
    and all practical suggestions are indeed welcomed.
     
    > > If you try the code that's committed, you'll see
    > that it does the
    > > right thing, something we've been unable to do in
    > the past. In
    > > particular, it passes the 'l' test, where you put
    > a bunch of l's
    > > interleaved with spaces, and hope that everything
    > linebreaks OK. This
    > > does not change when you change the zoom, and I
    > don't think it changes
    > > when you print either.

    And to finally clarify, this works perfectly in the
    printed PS output as well, for the first time ever.

    Cheers,
    Dom

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