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>

1 files changed, 76 insertions, 0 deletions

diff --git a/experimental/go-demo/main.go b/experimental/go-demo/main.go
new file mode 100644
index 0000000000..7df64d6e40
--- /dev/null
+++ b/experimental/go-demo/main.go
@@ -0,0 +1,76 @@
+/*
+ * 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 main
+
+/*
+	This is a translation of the example code in
+	"experimental/c-api-example/skia-c-example.c" to test the
+	go-skia package.
+*/
+
+import (
+	"log"
+	"os"
+
+	skia "skia.googlesource.com/skia/experimental/go-skia"
+)
+
+func main() {
+	imgInfo := &skia.ImageInfo{
+		Width:     640,
+		Height:    480,
+		ColorType: skia.GetDefaultColortype(),
+		AlphaType: skia.PREMUL_ALPHATYPE,
+	}
+
+	surface, err := skia.NewRasterSurface(imgInfo)
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	canvas := surface.Canvas()
+
+	fillPaint := skia.NewPaint()
+	fillPaint.SetColor(0xFF0000FF)
+	canvas.DrawPaint(fillPaint)
+	fillPaint.SetColor(0xFF00FFFF)
+
+	rect := skia.NewRect(100, 100, 540, 380)
+	canvas.DrawRect(rect, fillPaint)
+
+	strokePaint := skia.NewPaint()
+	strokePaint.SetColor(0xFFFF0000)
+	strokePaint.SetAntiAlias(true)
+	strokePaint.SetStroke(true)
+	strokePaint.SetStrokeWidth(5.0)
+
+	path := skia.NewPath()
+	path.MoveTo(50, 50)
+	path.LineTo(590, 50)
+	path.CubicTo(-490, 50, 1130, 430, 50, 430)
+	path.LineTo(590, 430)
+	canvas.DrawPath(path, strokePaint)
+
+	fillPaint.SetColor(0x8000FF00)
+	canvas.DrawOval(skia.NewRect(120, 120, 520, 360), fillPaint)
+
+	// // Get a skia image from the surface.
+	skImg := surface.Image()
+
+	// Write new image to file if we have one.
+	if skImg != nil {
+		out, err := os.Create("testimage.png")
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer out.Close()
+
+		if err := skImg.WritePNG(out); err != nil {
+			log.Fatalf("Unable to write png: %s", err)
+		}
+	}
+}