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get-transformation, etc. methods on dc<%>

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original commit: 06a47a3c54fb04ad598372303ff36b779f994e9c
This commit is contained in:
Matthew Flatt 2010-08-02 08:25:47 -06:00
parent 48367ad6a2
commit 6e114baa67
2 changed files with 25 additions and 9 deletions
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3
collects/scribblings/gui/blurbs.rkt
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@ -152,8 +152,7 @@ information@|details|, even if the editor currently has delayed refreshing (see
(define SeeMzParam @elem{(see @secref[#:doc reference-doc "parameters"])})
(define DrawSizeNote @elem{Restrictions on the magnitude of
drawing coordinates are described with @scheme[dc<%>].})
(define DrawSizeNote "")
(define LineNumbering @elem{Lines are numbered starting with @scheme[0].})
(define ParagraphNumbering @elem{Paragraphs are numbered starting with @scheme[0].})

31
doc/release-notes/racket/Draw_and_GUI_5_5.txt
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@ -29,23 +29,40 @@ Changes to the drawing toolbox:
* A `dc<%>' supports additional drawing transformations: a rotation
(via `set-rotation') and a general transformation matrix (via
`set-initial-matrix').
`set-initial-matrix'). Scaling factors can be negative, which
corresponds to flipping the direction of drawing.
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.
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 a little redundant, since
all transformations could be expressed in a single matrix, but it
is backward compatibile.
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.
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.
* The old 'xor mode for pens and brushes is no longer available
(since it is not supported by Cairo).
Changes to the GUI toolbox: