diff options
author | Stephan Altmueller <stephana@google.com> | 2017-05-09 15:56:06 -0400 |
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committer | Skia Commit-Bot <skia-commit-bot@chromium.org> | 2017-05-10 15:32:19 +0000 |
commit | efa48d599de15d960d7335a4a93a6bbeb97d3c41 (patch) | |
tree | 6b95700087faeaaec0ea030d0fa5e17b515cebc1 /experimental/go-skia/skia.go | |
parent | 05fd8cf08970763832d6690ca1823168dd6f071f (diff) |
Experimental Go bindings for Skia
This CL implements Go bindings for a subset of the functions in the C API.
It implements a Go version of the C demo program in
experimental/c-api-example/skia-c-example.c and the output is identical.
(Checked by hand).
The main purpose is to establish a pattern of calling the Skia C API that
is memory safe and provides a idiomatic Go interface to Skia.
Follow up CLs will cover the entire C API, add documentation and establish
a pattern to distribute the bindings more easily.
BUG=
Change-Id: I96ff7c3715164c533202ce300ab0312b1b07f884
Change-Id: I96ff7c3715164c533202ce300ab0312b1b07f884
Reviewed-on: https://skia-review.googlesource.com/10032
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Stephan Altmueller <stephana@google.com>
Diffstat (limited to 'experimental/go-skia/skia.go')
-rw-r--r-- | experimental/go-skia/skia.go | 223 |
1 files changed, 199 insertions, 24 deletions
diff --git a/experimental/go-skia/skia.go b/experimental/go-skia/skia.go index 30730578a7..e477593dc8 100644 --- a/experimental/go-skia/skia.go +++ b/experimental/go-skia/skia.go @@ -1,38 +1,213 @@ -package main - -// First, build Skia this way: -// ./gyp_skia -Dskia_shared_lib=1 && ninja -C out/Debug +/* + * Copyright 2015 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ +package skia /* -#cgo LDFLAGS: -lGL -#cgo LDFLAGS: -lGLU -#cgo LDFLAGS: -lX11 -#cgo LDFLAGS: -ldl -#cgo LDFLAGS: -lfontconfig -#cgo LDFLAGS: -lfreetype -#cgo LDFLAGS: -lgif -#cgo LDFLAGS: -lm -#cgo LDFLAGS: -lpng -#cgo LDFLAGS: -lstdc++ -#cgo LDFLAGS: -lz - -#cgo LDFLAGS: -L ../../out/Debug/lib -#cgo LDFLAGS: -Wl,-rpath=../../out/Debug/lib +#cgo LDFLAGS: -L${SRCDIR}/../../out/Shared +#cgo LDFLAGS: -Wl,-rpath=${SRCDIR}/../../out/Shared #cgo LDFLAGS: -lskia - #cgo CFLAGS: -I../../include/c +#include "sk_canvas.h" +#include "sk_data.h" +#include "sk_image.h" +#include "sk_paint.h" +#include "sk_path.h" #include "sk_surface.h" */ import "C" import ( "fmt" + "io" + "runtime" + "unsafe" ) -func main() { - p := C.sk_paint_new() - defer C.sk_paint_delete(p) - fmt.Println("OK!") +// TODO(stephana): Add proper documentation to the types defined here. + +////////////////////////////////////////////////////////////////////////// +// Surface +////////////////////////////////////////////////////////////////////////// +type Surface struct { + ptr *C.sk_surface_t +} + +// func NewRasterSurface(width, height int32, alphaType AlphaType) (*Surface, error) { +func NewRasterSurface(imgInfo *ImageInfo) (*Surface, error) { + ptr := C.sk_surface_new_raster(imgInfo.cPointer(), (*C.sk_surfaceprops_t)(nil)) + if ptr == nil { + return nil, fmt.Errorf("Unable to create raster surface.") + } + + ret := &Surface{ptr: ptr} + runtime.SetFinalizer(ret, func(s *Surface) { + C.sk_surface_unref(s.ptr) + }) + return ret, nil +} + +func (s *Surface) Canvas() *Canvas { + return &Canvas{ + ptr: C.sk_surface_get_canvas(s.ptr), + keepParentAlive: s, + } +} + +func (s *Surface) Image() *Image { + ret := &Image{ + ptr: C.sk_surface_new_image_snapshot(s.ptr), + keepParentAlive: s, + } + runtime.SetFinalizer(ret, func(i *Image) { + C.sk_image_unref(i.ptr) + }) + return ret +} + +////////////////////////////////////////////////////////////////////////// +// Image +////////////////////////////////////////////////////////////////////////// +type Image struct { + ptr *C.sk_image_t + keepParentAlive *Surface +} + +func (i *Image) WritePNG(w io.Writer) error { + data := C.sk_image_encode(i.ptr) + defer C.sk_data_unref(data) + + dataPtr := C.sk_data_get_data(data) + dataSize := C.sk_data_get_size(data) + byteSlice := C.GoBytes(dataPtr, C.int(dataSize)) + _, err := w.Write(byteSlice) + if err != nil { + return err + } + return nil } -// TODO: replace this with an idiomatic interface to Skia. +////////////////////////////////////////////////////////////////////////// +// Canvas +////////////////////////////////////////////////////////////////////////// +type Canvas struct { + ptr *C.sk_canvas_t + keepParentAlive *Surface +} + +func (c *Canvas) DrawPaint(paint *Paint) { + C.sk_canvas_draw_paint(c.ptr, paint.ptr) +} + +func (c *Canvas) DrawOval(rect *Rect, paint *Paint) { + // C.sk_canvas_draw_oval(c.ptr, (*C.sk_rect_t)(unsafe.Pointer(rect)), (*C.sk_paint_t)(paint.ptr)) + C.sk_canvas_draw_oval(c.ptr, rect.cPointer(), paint.ptr) +} + +func (c *Canvas) DrawRect(rect *Rect, paint *Paint) { + // C.sk_canvas_draw_rect(c.ptr, (*C.sk_rect_t)(unsafe.Pointer(rect)), (*C.sk_paint_t)(paint.ptr)) + C.sk_canvas_draw_rect(c.ptr, rect.cPointer(), paint.ptr) +} + +func (c *Canvas) DrawPath(path *Path, paint *Paint) { + // C.sk_canvas_draw_path(c.ptr, (*C.sk_path_t)(path.ptr), (*C.sk_paint_t)(paint.ptr)) + C.sk_canvas_draw_path(c.ptr, path.ptr, paint.ptr) +} + +////////////////////////////////////////////////////////////////////////// +// Paint +////////////////////////////////////////////////////////////////////////// +type Paint struct { + ptr *C.sk_paint_t +} + +func NewPaint() *Paint { + ret := &Paint{ptr: C.sk_paint_new()} + runtime.SetFinalizer(ret, func(p *Paint) { + C.sk_paint_delete(p.ptr) + }) + return ret +} + +func (p *Paint) SetColor(color Color) { + C.sk_paint_set_color(p.ptr, C.sk_color_t(color)) +} + +func (p *Paint) SetAntiAlias(antiAlias bool) { + C.sk_paint_set_antialias(p.ptr, C._Bool(antiAlias)) +} + +func (p *Paint) SetStroke(val bool) { + C.sk_paint_set_stroke(p.ptr, C._Bool(val)) +} + +func (p *Paint) SetStrokeWidth(width float32) { + C.sk_paint_set_stroke_width(p.ptr, C.float(width)) +} + +////////////////////////////////////////////////////////////////////////// +// Path +////////////////////////////////////////////////////////////////////////// +type Path struct { + ptr *C.sk_path_t +} + +func NewPath() *Path { + ret := &Path{ptr: C.sk_path_new()} + runtime.SetFinalizer(ret, func(p *Path) { + C.sk_path_delete(p.ptr) + }) + return ret +} + +func (p *Path) MoveTo(x, y float32) { + C.sk_path_move_to(p.ptr, C.float(x), C.float(y)) +} + +func (p *Path) LineTo(x, y float32) { + C.sk_path_line_to(p.ptr, C.float(x), C.float(y)) +} + +func (p *Path) QuadTo(x0, y0, x1, y1 float32) { + C.sk_path_quad_to(p.ptr, C.float(x0), C.float(y0), C.float(x1), C.float(y1)) +} + +func (p *Path) ConicTo(x0, y0, x1, y1, w float32) { + C.sk_path_conic_to(p.ptr, C.float(x0), C.float(y0), C.float(x1), C.float(y1), C.float(w)) +} + +func (p *Path) CubicTo(x0, y0, x1, y1, x2, y2 float32) { + C.sk_path_cubic_to(p.ptr, C.float(x0), C.float(y0), C.float(x1), C.float(y1), C.float(x2), C.float(y2)) +} + +func (p *Path) Close() { + C.sk_path_close(p.ptr) +} + +// NewRect is a convenience function to define a Rect in a single line. +func NewRect(left, top, right, bottom float32) *Rect { + return &Rect{ + Left: left, + Top: top, + Right: right, + Bottom: bottom, + } +} + +// cPointer casts the pointer to Rect to the corresponding C pointer. +func (r *Rect) cPointer() *C.sk_rect_t { + return (*C.sk_rect_t)(unsafe.Pointer(r)) +} + +// cPointer casts the pointer to ImageInfo to the corresponding C pointer. +func (i *ImageInfo) cPointer() *C.sk_imageinfo_t { + return (*C.sk_imageinfo_t)(unsafe.Pointer(i)) +} + +// Utility functions. +func GetDefaultColortype() ColorType { + return ColorType(C.sk_colortype_get_default_8888()) +} |