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41 lines
989 B
41 lines
989 B
// Copyright 2011 The Graphics-Go Authors. All rights reserved. |
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// Use of this source code is governed by a BSD-style |
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// license that can be found in the LICENSE file. |
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package graphics |
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import ( |
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"image" |
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"image/draw" |
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) |
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// Thumbnail scales and crops src so it fits in dst. |
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func Thumbnail(dst draw.Image, src image.Image) error { |
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// Scale down src in the dimension that is closer to dst. |
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sb := src.Bounds() |
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db := dst.Bounds() |
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rx := float64(sb.Dx()) / float64(db.Dx()) |
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ry := float64(sb.Dy()) / float64(db.Dy()) |
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var b image.Rectangle |
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if rx < ry { |
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b = image.Rect(0, 0, db.Dx(), int(float64(sb.Dy())/rx)) |
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} else { |
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b = image.Rect(0, 0, int(float64(sb.Dx())/ry), db.Dy()) |
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} |
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buf := image.NewRGBA(b) |
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if err := Scale(buf, src); err != nil { |
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return err |
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} |
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// Crop. |
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// TODO(crawshaw): improve on center-alignment. |
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var pt image.Point |
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if rx < ry { |
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pt.Y = (b.Dy() - db.Dy()) / 2 |
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} else { |
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pt.X = (b.Dx() - db.Dx()) / 2 |
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} |
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draw.Draw(dst, db, buf, pt, draw.Src) |
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return nil |
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}
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