Added get-path-bounding-box.
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Jens Axel Søgaard
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commit
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@ -621,6 +621,36 @@ See also @method[dc<%> set-origin] and @method[dc<%> get-transformation].
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Gets the current pen. See also @method[dc<%> set-pen].
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}
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@defmethod[(get-path-bounding-box [path (is-a?/c dc-path%)]
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[type (or/c 'path 'stroke 'fill)])
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(values real? real? real? real?)]{
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Returns a rectangle that encloses the path’s points.
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The return values are the left, top, width, and, height of the rectangle.
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The numbers are in logical coordinates.
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For the type @racket['stroke] the rectangle covers the area that would be affected ("inked")
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when drawn with the current pen by draw-path in the drawing context (with a transparent brush).
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If the pen width is zero, then an empty rectangle will be returned. The size and clipping of the
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drawing context is ignored.
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For the type @racket['fill] the rectangle covers the area that would be affected ("inked")
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by draw-path in the drawing context (with a non-transparent pen and brush). If the line width
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is zero, then an empty rectangle will be returned. The size and clipping of the drawing
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context are ignored.
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For the type @racket['path] the rectangle covers the path, but the pen and brush are ignored.
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The size and clipping of the drawing context are also ignored.
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More precisely: The result is defined as the limit of the bounding boxes returned
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by the 'stroke type for line widths approaching 0 with a round pen cap. The "limit
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process" stops when an empty rectangle is returned. This that zero-area segments contributes
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the rectangle.
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For all types if the path is empty, then an empty rectangle @racket[(values 0 0 0 0)]
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will be returned.
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}
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@defmethod[(get-rotation) real?]{
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@ -33,7 +33,7 @@
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(define dc-path%
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(class object%
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;; A path is a list of pairs and vectors:
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;; * The pairs corerspond to points on the path
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;; * The pairs correspond to points on the path
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;; * A vector must be between two pairs; it specifies
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;; control points for a curve between the two points.
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@ -173,6 +173,26 @@
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(max b (vector-ref p 1) (vector-ref p 3)))]))])
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(values l t (- r l) (- b t))))))
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(define/public (do-get-path-bounding-box cr type align-x align-y)
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(flatten-closed!)
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(flatten-open!)
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(if (and (null? closed-points)
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(null? open-points)
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(not cr))
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(values 0. 0. 0. 0.)
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(let ()
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(define cairo_op
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(cond
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[(eq? type 'path) cairo_path_extents]
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[(eq? type 'fill) cairo_fill_extents]
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[(eq? type 'stroke) cairo_stroke_extents]
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[else (error 'get-tight-binding-boc "expected 'path, 'fill, or, 'stroke")]))
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(cairo_save cr)
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(do-path cr align-x align-y)
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(define-values (x1 y1 x2 y2) (cairo_op cr))
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(cairo_restore cr)
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(values x1 y1 y2 y2))))
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(define/public (move-to x y)
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(when (or (pair? open-points)
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(pair? rev-open-points))
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@ -1134,6 +1134,15 @@
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(rounded-rect x y (sub1w width) (sub1h height)
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(lambda (x) (align-x x)) (lambda (y) (align-y y)))
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(draw cr #f #t)))))
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(define (bounding-box-type? o) (member o '(path fill stroke)))
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(def/public (get-path-bounding-box [dc-path% path] [bounding-box-type? type])
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(with-cr
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(values 0. 0. 0. 0.)
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cr
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(send path do-get-path-bounding-box cr type
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(lambda (x) (align-x x)) (lambda (y) (align-y y)))))
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(def/public (draw-spline [real? x1] [real? y1] [real? x2] [real? y2] [real? x3] [real? y3])
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(with-cr
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@ -125,6 +125,22 @@
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(set! warned? #t))
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(values 0 0 0 0)))))
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(define-cairo cairo_fill_extents (_cfun _cairo_t
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(x1 : (_ptr o _double))
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(y1 : (_ptr o _double))
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(x2 : (_ptr o _double))
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(y2 : (_ptr o _double))
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-> _void
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-> (values x1 y1 x2 y2)))
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(define-cairo cairo_stroke_extents (_cfun _cairo_t
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(x1 : (_ptr o _double))
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(y1 : (_ptr o _double))
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(x2 : (_ptr o _double))
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(y2 : (_ptr o _double))
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-> _void
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-> (values x1 y1 x2 y2)))
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;; Transforms
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(define-cairo cairo_translate (_cfun _cairo_t _double* _double* -> _void))
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(define-cairo cairo_scale (_cfun _cairo_t _double* _double* -> _void))
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@ -440,6 +456,22 @@
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(define-cairo cairo_copy_path (_cfun _cairo_t -> _cairo_path_t-pointer)
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#:wrap (allocator cairo_path_destroy))
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(define-cairo cairo_path_extents (_cfun _cairo_t
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(x1 : (_ptr o _double))
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(y1 : (_ptr o _double))
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(x2 : (_ptr o _double))
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(y2 : (_ptr o _double))
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-> _void
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-> (values x1 y1 x2 y2))
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;; cairo_path_extents is in version 1.6 and later
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#:fail (lambda ()
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(let ([warned? #f])
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(lambda (cr)
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(unless warned?
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(log-warning "cairo_path_extents is unavailable; returning the empty rectangle")
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(set! warned? #t))
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(values 0 0 0 0)))))
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(define-enum 0
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CAIRO_PATH_MOVE_TO
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CAIRO_PATH_LINE_TO
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