add sample: linecapjoin

samples/linecapjoin/linecapjoin.go

@@ -0,0 +1,54 @@
+// Copyright 2010 The draw2d Authors. All rights reserved.
+// created: 21/11/2010 by Laurent Le Goff
+
+// Package linecapjoin demonstrates the different line caps and joins.
+package linecapjoin
+
+import (
+	"image/color"
+
+	"github.com/llgcode/draw2d"
+	"github.com/llgcode/draw2d/samples"
+)
+
+// Main draws the different line caps and joins.
+// This should only be used during testing.
+func Main(gc draw2d.GraphicContext, ext string) (string, error) {
+	// Draw the line
+	const offset = 75.0
+	x := 35.0
+	caps := []draw2d.Cap{draw2d.ButtCap, draw2d.SquareCap, draw2d.RoundCap}
+	joins := []draw2d.Join{draw2d.BevelJoin, draw2d.MiterJoin, draw2d.RoundJoin}
+	for i := range caps {
+		Draw(gc, caps[i], joins[i], x, 50, x, 160, offset)
+		x += offset
+	}
+
+	// Return the output filename
+	return samples.Output("linecapjoin", ext), nil
+}
+
+// Draw a line with an angle with specified line cap and join
+func Draw(gc draw2d.GraphicContext, cap draw2d.Cap, join draw2d.Join,
+	x0, y0, x1, y1, offset float64) {
+	gc.Save() // pdf: save & restore needed to isolate caps and joins
+	gc.SetLineCap(cap)
+	gc.SetLineJoin(join)
+
+	// Draw thick line
+	gc.SetStrokeColor(color.NRGBA{0x33, 0x33, 0x33, 0xFF})
+	gc.SetLineWidth(30.0)
+	gc.MoveTo(x0, y0)
+	gc.LineTo((x0+x1)/2+offset, (y0+y1)/2)
+	gc.LineTo(x1, y1)
+	gc.Stroke()
+
+	// Draw thin helping line
+	gc.SetStrokeColor(color.NRGBA{0xFF, 0x33, 0x33, 0xFF})
+	gc.SetLineWidth(2.56)
+	gc.MoveTo(x0, y0)
+	gc.LineTo((x0+x1)/2+offset, (y0+y1)/2)
+	gc.LineTo(x1, y1)
+	gc.Stroke()
+	gc.Restore()
+}