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Diffstat (limited to 'vendor/golang.org/x/image/draw/draw.go')
-rw-r--r-- | vendor/golang.org/x/image/draw/draw.go | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/vendor/golang.org/x/image/draw/draw.go b/vendor/golang.org/x/image/draw/draw.go new file mode 100644 index 000000000..b92e3c7f9 --- /dev/null +++ b/vendor/golang.org/x/image/draw/draw.go @@ -0,0 +1,79 @@ +// Copyright 2015 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package draw provides image composition functions. +// +// See "The Go image/draw package" for an introduction to this package: +// http://golang.org/doc/articles/image_draw.html +// +// This package is a superset of and a drop-in replacement for the image/draw +// package in the standard library. +package draw + +// This file just contains the API exported by the image/draw package in the +// standard library. Other files in this package provide additional features. + +import ( + "image" + "image/color" + "image/draw" +) + +// Draw calls DrawMask with a nil mask. +func Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point, op Op) { + draw.Draw(dst, r, src, sp, draw.Op(op)) +} + +// DrawMask aligns r.Min in dst with sp in src and mp in mask and then +// replaces the rectangle r in dst with the result of a Porter-Duff +// composition. A nil mask is treated as opaque. +func DrawMask(dst Image, r image.Rectangle, src image.Image, sp image.Point, mask image.Image, mp image.Point, op Op) { + draw.DrawMask(dst, r, src, sp, mask, mp, draw.Op(op)) +} + +// Drawer contains the Draw method. +type Drawer interface { + // Draw aligns r.Min in dst with sp in src and then replaces the + // rectangle r in dst with the result of drawing src on dst. + Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point) +} + +// FloydSteinberg is a Drawer that is the Src Op with Floyd-Steinberg error +// diffusion. +var FloydSteinberg Drawer = floydSteinberg{} + +type floydSteinberg struct{} + +func (floydSteinberg) Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point) { + draw.FloydSteinberg.Draw(dst, r, src, sp) +} + +// Image is an image.Image with a Set method to change a single pixel. +type Image interface { + image.Image + Set(x, y int, c color.Color) +} + +// Op is a Porter-Duff compositing operator. +type Op int + +const ( + // Over specifies ``(src in mask) over dst''. + Over Op = Op(draw.Over) + // Src specifies ``src in mask''. + Src Op = Op(draw.Src) +) + +// Draw implements the Drawer interface by calling the Draw function with +// this Op. +func (op Op) Draw(dst Image, r image.Rectangle, src image.Image, sp image.Point) { + (draw.Op(op)).Draw(dst, r, src, sp) +} + +// Quantizer produces a palette for an image. +type Quantizer interface { + // Quantize appends up to cap(p) - len(p) colors to p and returns the + // updated palette suitable for converting m to a paletted image. + Quantize(p color.Palette, m image.Image) color.Palette +} |