[racket-dev] try the GRacket2 branch

The version number on GRacket2 right now is 5.0.2.2.

At Thu, 28 Oct 2010 11:26:43 -0600, Jon Rafkind wrote:
> Maybe I screwed something up but I can't tell if I'm running gr2 or not.
> I built the gr2 branch and ran drscheme but so far it looks exactly the
> same as gr1 (which I am positive is actually gr1).
> 
> Is there an easy way to tell if I'm running gr2? Or should gr2 look
> identical to gr1?
> 
> On 10/28/2010 12:25 AM, Matthew Flatt wrote:
> > The git repository now includes a "gr2" branch for the new
> > implementation of `racket/gui', which we've been informally calling
> > "GRacket2".
> >
> > The new `racket/gui' is intended to be mostly compatible with the
> > current library, but there are some significant incompatibilities.
> > Those differences are described below in a copy of the "Porting from
> > v5.0.x to vX.Y" notes that are linked from the "Release Notes" page of
> > the documentation.
> >
> > "GRacket2" is a misnomer in the sense that you can use the new
> > `racket/gui' with just `racket'. Furthermore, the drawing layer is
> > mostly unbundled from the GUI layer into a separate `racket/draw'
> > library, so you can manipulate images without a GUI (e.g., without an
> > X11 connection). The documentation doesn't yet reflect the GUI--Draw
> > split, Slideshow's pict library doesn't yet use `racket/draw', etc.,
> > but I hope to get to that next.
> >
> > More immediately, it's time for you to try out the "gr2" branch for
> > everyday work. I've switched to GRacket2 for SirMail, Slideshow, and
> > DrRacket --- even during lecture. All library functionality is in
> > place, but I'm sure that gaps and problems will show up as we put the
> > library to work (and I know that some of the tests still fail). I
> > expect to see many bug reports; once the bug reports slow down, I'll
> > take that as a sign that GRacket2 can move to master branch.
> >
> > ----------------------------------------
> >
> > GRacket, Racket, Drawing, and GUIs
> > ----------------------------------
> >
> > Version X.Y includes two major changes to the Racket drawing and GUI
> > API:
> >
> >  * The drawing portion of the GUI toolbox is now available as a
> >    separate layer: `racket/draw'. This layer can be used independent
> >    of the `racket/gui/base' library, although `racket/gui' re-exports
> >    `racket/draw'.
> >
> >    (The `racket/draw' library is built on top of the widely used Cairo
> >    drawing library and Pango text-rendering library.)
> >
> >  * The GRacket executable is no longer strictly necessary for running
> >    GUI programs; the `racket/gui/base' library can be used from
> >    Racket.
> >
> >    The GRacket executable still offers some additional GUI-specific
> >    functiontality however. Most notably, GRacket is a GUI application
> >    under Windows (as opposed to a console application, which is
> >    launched slightly differently by the OS), GRacket is a bundle under
> >    Mac OS X (so the dock icon is the Racket logo, for example), and
> >    GRacket manages single-instance mode for Windows and X.
> >
> > The drawing and GUI libraries have also changed in further small ways.
> >
> >
> > Bitmaps
> > -------
> >
> > Drawing to a bitmap may not produce the same results as drawing to a
> > canvas. Use the `make-screen-bitmap' function (from `racket/gui') or
> > the `make-bitmap' method of `canvas%' to obtain a bitmap that uses the
> > same drawing algorithms as a canvas.
> >
> > A color bitmap can have an alpha channel, instead of just a mask
> > bitmap. When drawing a bitmap, alpha channels are used more
> > consistently and automatically than mask bitmaps. More significantly,
> > drawing into a bitmap with an alpha channel preserves the drawn
> > alphas; for example, drawing a line in the middle of an empty bitmap
> > produces an image with non-zero alpha only at the drawn line.
> >
> > Only bitmaps created with the new `make-gl-bitmap' function support
> > OpenGL drawing.
> >
> > Use the new `make-bitmap', `read-bitmap', `make-monochrome-bitmap',
> > `make-screen-bitmap', and `make-gl-bitmap' functions to create
> > bitmaps, instead of using `make-object' with `bitmap%'. The new
> > constructors are less overloaded and provide more modern defaults
> > (such as alpha channels by default).
> >
> > Image formats can be read into a `bitmap%' from from input ports,
> > instead of requiring a file path. A newly created bitmap has an empty
> > content (i.e., white with zero alpha), instead of unspecified content.
> >
> >
> > Canvases
> > --------
> >
> > Drawing to a canvas always draws into a bitmap that is kept offscreen
> > and periodically flushed onto the screen. The new `suspend-flush' and
> > `resume-flush' methods of `canvas%' provide some control over the
> > timing of the flushes, which in many cases avoids the need for
> > (additional) double buffering of canvas content.
> >
> > OpenGL drawing in a canvas requires supplying 'gl as a style when
> > creating the `canvas%' instance. OpenGL and normal dc<%> drawing no
> > longer mix reliably in a canvas.
> >
> >
> > Drawing-Context Transformations
> > -------------------------------
> >
> > A `dc<%>' instance supports rotation (via `set-rotation'), negative
> > scaling factors for flipping, and a general transformation matrix (via
> > `set-initial-matrix'). A transformation matrix has the form `(vector
> > xx xy yx yy x0 y0)', where a point (x1, y1) is transformed to a point
> > (x2, y2) with x2 = xx*x1 + yx*y1 + x0 and y2 = xy*x1 + yy*y1 + y0,
> > which is the usual convention.
> >
> > New methods `translate', `scale', `rotate', and `transform' simplify
> > adding a further translation, scaling, rotation, or arbitrary matrix
> > transformation on top of the current transformation. The new
> > `get-translation' and `set-translation' methods help to capture and
> > restore transformation settings.
> >
> > The old translation and scaling transformations apply after the
> > initial matrix. The new rotation transformation applies after the
> > other transformations. This layering is redundant, since all
> > transformations can be expressed in a single matrix, but it is
> > backward-compatibile. Methods like `get-translation',
> > `set-translation', `scale', etc. help hide the reundancy.
> >
> >
> > Others Drawing-Context Changes
> > ------------------------------
> >
> > The alpha value of a `dc<%>' (as set by `set-alpha') is used for all
> > drawing operations, including drawing a bitmap.
> >
> > The `draw-bitmap' and `draw-bitmap-section' methods now smooth bitmaps
> > while scaling, so the `draw-bitmap-section-smooth' method of
> > `bitmap-dc%' simply calls `draw-bitmap-section'.
> >
> > A `region%' can be created as independent of any `dc<%>', in which
> > cases it uses the drawing context's current transformation at the time
> > that it is installed as a clipping region.
> >
> > The old 'xor mode for pens and brushes is no longer available (since
> > it is not supported by Cairo).
> >
> >
> > Editor Changes
> > --------------
> >
> > The `draw-caret' argument to a `snip%' or `editor<%>' `draw' or
> > `refresh' method can be a pair, which indicates that the caret is
> > owned by an enclosing display and the selection spans the snip or
> > editor. In that case, the snip or editor should refrain from drawing a
> > background for the selected region, and it should draw the foreground
> > in the color specified by `get-highlight-text-color', if any.
> >
> >
> > Removed Functions
> > -----------------
> >
> > The `write-resource, `get-reource', and `send-event' functions have
> > been removed from `racket/gui/base'. If there is any demand for the
> > removed functionality, it will be implemented in a new library.
> >
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