85 lines
3 KiB
Go
85 lines
3 KiB
Go
// Copyright 2010 The draw2d Authors. All rights reserved.
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// created: 13/12/2010 by Laurent Le Goff
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// Package draw2d is a pure go 2D vector graphics library with support
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// for multiple output devices such as images (draw2d), pdf documents
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// (draw2dpdf) and opengl (draw2dgl), which can also be used on the
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// google app engine. It can be used as a pure go Cairo alternative.
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// draw2d is released under the BSD license.
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//
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// Features
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//
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// Operations in draw2d include stroking and filling polygons, arcs,
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// Bézier curves, drawing images and text rendering with truetype fonts.
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// All drawing operations can be transformed by affine transformations
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// (scale, rotation, translation).
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//
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// Package draw2d follows the conventions of http://www.w3.org/TR/2dcontext for coordinate system, angles, etc...
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//
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// Installation
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//
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// To install or update the package draw2d on your system, run:
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// go get -u github.com/llgcode/draw2d
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//
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// Quick Start
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//
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// Package draw2d itself provides a graphic context that can draw vector
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// graphics and text on an image canvas. The following Go code
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// generates a simple drawing and saves it to an image file:
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// // Initialize the graphic context on an RGBA image
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// dest := image.NewRGBA(image.Rect(0, 0, 297, 210.0))
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// gc := draw2d.NewGraphicContext(dest)
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//
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// // Set some properties
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// gc.SetFillColor(color.RGBA{0x44, 0xff, 0x44, 0xff})
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// gc.SetStrokeColor(color.RGBA{0x44, 0x44, 0x44, 0xff})
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// gc.SetLineWidth(5)
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//
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// // Draw a closed shape
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// gc.MoveTo(10, 10) // should always be called first for a new path
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// gc.LineTo(100, 50)
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// gc.QuadCurveTo(100, 10, 10, 10)
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// gc.Close()
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// gc.FillStroke()
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//
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// // Save to file
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// draw2d.SaveToPngFile("hello.png", dest)
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//
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// There are more examples here:
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// https://github.com/llgcode/draw2d/tree/master/samples
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//
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// Drawing on pdf documents is provided by the draw2dpdf package.
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// Drawing on opengl is provided by the draw2dgl package.
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// See subdirectories at the bottom of this page.
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//
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// Testing
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//
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// The samples are run as tests from the root package folder `draw2d` by:
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// go test ./...
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//
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// Or if you want to run with test coverage:
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// go test -cover ./... | grep -v "no test"
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//
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// This will generate output by the different backends in the output folder.
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//
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// Acknowledgments
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//
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// Laurent Le Goff wrote this library, inspired by Postscript and
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// HTML5 canvas. He implemented the image and opengl backend with the
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// freetype-go package. Also he created a pure go Postscript
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// interpreter, which can read postscript images and draw to a draw2d
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// graphic context (https://github.com/llgcode/ps). Stani Michiels
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// implemented the pdf backend with the gofpdf package.
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//
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// Packages using draw2d
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//
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// - https://github.com/llgcode/ps: Postscript interpreter written in Go
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//
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// - https://github.com/gonum/plot: drawing plots in Go
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//
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// - https://github.com/muesli/smartcrop: content aware image cropping
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//
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// - https://github.com/peterhellberg/karta: drawing Voronoi diagrams
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//
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// - https://github.com/vdobler/chart: basic charts in Go
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package draw2d
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