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April 7, 2016 14:33
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Demonstrate how to rotate and then crop image.
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// http://dev.pawelsz.eu/2016/04/go-imagick-image-croping-after-rotation.html | |
// | |
package main | |
import ( | |
"gopkg.in/gographics/imagick.v2/imagick" | |
"log" | |
"math" | |
) | |
func minUint(a, b uint) uint { | |
if a < b { | |
return a | |
} | |
return b | |
} | |
func calcSize(w, h uint) uint { | |
return uint(math.Sqrt(2.) / 2. * float64(minUint(w, h))) | |
} | |
func main() { | |
s := "example.jpeg" | |
d := "example.cut.jpeg" | |
iwand := imagick.NewMagickWand() | |
defer iwand.Destroy() | |
if err := iwand.ReadImage(s); err != nil { | |
log.Panicf("cannot open image %s", err) | |
} | |
w := iwand.GetImageWidth() | |
h := iwand.GetImageHeight() | |
log.Printf("old size: %d,%d", w, h) | |
pwand := imagick.NewPixelWand() | |
pwand.SetColor("yellow") | |
if err := iwand.RotateImage(pwand, 45); err != nil { | |
log.Panicf("problem with rotation: %s", err) | |
} | |
newW := calcSize(w, h) | |
newH := newW | |
w = iwand.GetImageWidth() | |
h = iwand.GetImageHeight() | |
log.Printf("new size: %d,%d", w, h) | |
x := int((w - newW) / 2) | |
y := int((h - newH) / 2) | |
// draw red rectangle around the area | |
dwand := imagick.NewDrawingWand() | |
pwand.SetColor("red") | |
pwand.SetOpacity(0.5) | |
dwand.SetFillColor(pwand) | |
dwand.Rectangle(float64(x), float64(y), float64(newW+uint(x)), float64(newH+uint(y))) | |
iwand.DrawImage(dwand) | |
log.Printf("w,h,x,y: %d,%d,%d,%d", newW, newH, x, y) | |
iwand.ResetImagePage("") | |
if err := iwand.CropImage(newW, newH, x, y); err != nil { | |
log.Fatalf("problem with crop: %s", err) | |
} | |
iwand.WriteImage(d) | |
} |
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