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