added an example as documentation and test

pdf2d/graphiccontext_test.go

@@ -0,0 +1,35 @@
+package pdf2d
+
+import (
+	"fmt"
+	"image/color"
+
+	"github.com/stanim/draw2d"
+	"github.com/stanim/gofpdf"
+)
+
+func ExampleGraphicContext() {
+	// Initialize the graphic context on a pdf document
+	pdf := gofpdf.New("P", "mm", "A4", "../font")
+	pdf.AddPage()
+	gc := NewGraphicContext(pdf)
+
+	// some properties
+	gc.SetFillColor(color.RGBA{0x44, 0xff, 0x44, 0xff})
+	gc.SetStrokeColor(color.RGBA{0x44, 0x44, 0x44, 0xff})
+	gc.SetLineCap(draw2d.RoundCap)
+	gc.SetLineWidth(5)
+
+	// draw something
+	gc.MoveTo(10, 10) // should always be called for a new path
+	gc.LineTo(100, 50)
+	gc.QuadCurveTo(100, 10, 10, 10)
+	gc.Close()
+	gc.FillStroke()
+	fmt.Println(gc.LastPoint())
+
+	// pdf2d.SaveToPdfFile("example.pdf", pdf)
+
+	// Output:
+	// 10 10
+}