4f197f4ba9
The `get-handle' method provides the underlying Cairo surface for a bitmap, while the unsafe `make-handle-brush' function supports the use of a Cairo surface as a `brush%'. Also, add `racket/draw/unsafe/cairo-lib', which simplifies access Cairo from external libraries. Documenting `racket/draw/unsafe/cairo' might be better, but that's a lot more work.
37 lines
1.3 KiB
Racket
37 lines
1.3 KiB
Racket
#lang racket/base
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(require ffi/unsafe
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racket/draw/unsafe/cairo-lib
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racket/draw/unsafe/brush)
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(provide surface-brush)
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(define cairo_image_surface_create
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(get-ffi-obj 'cairo_image_surface_create cairo-lib (_fun _int _int _int -> _pointer)))
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(define cairo_surface_destroy
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(get-ffi-obj 'cairo_surface_destroy cairo-lib (_fun _pointer -> _void)))
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(define cairo_create
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(get-ffi-obj 'cairo_create cairo-lib (_fun _pointer -> _pointer)))
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(define cairo_destroy
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(get-ffi-obj 'cairo_destroy cairo-lib (_fun _pointer -> _void)))
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(define cairo_set_source_rgba
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(get-ffi-obj 'cairo_set_source_rgba cairo-lib (_fun _pointer _double* _double* _double* _double* -> _void)))
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(define cairo_rectangle
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(get-ffi-obj 'cairo_rectangle cairo-lib (_fun _pointer _double* _double* _double* _double* -> _void)))
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(define cairo_fill
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(get-ffi-obj 'cairo_fill cairo-lib (_fun _pointer -> _void)))
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(define s (cairo_image_surface_create 0 20 30))
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(define cr (cairo_create s))
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(cairo_set_source_rgba cr 1.0 0.0 0.0 0.5)
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(cairo_rectangle cr 2 2 16 26)
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(cairo_fill cr)
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(cairo_set_source_rgba cr 0.0 0.0 0.0 1.0)
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(cairo_rectangle cr 9 9 2 2)
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(cairo_fill cr)
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(cairo_destroy cr)
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(define surface-brush (make-handle-brush s 20 30 '#(#(1 0 0 1 420 320) 0 0 1 1 0)))
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(cairo_surface_destroy s)
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