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author | Christopher Speller <crspeller@gmail.com> | 2017-02-02 09:32:00 -0500 |
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committer | Harrison Healey <harrisonmhealey@gmail.com> | 2017-02-02 09:32:00 -0500 |
commit | 701d1ab638b23c24877fc41824add66232446676 (patch) | |
tree | ec120c88d38ac9d38d9eabdd3270b52bb6ac9d96 /vendor/github.com/disintegration/imaging/histogram.go | |
parent | ca3211bc04f6dea34e8168217182637d1419f998 (diff) | |
download | chat-701d1ab638b23c24877fc41824add66232446676.tar.gz chat-701d1ab638b23c24877fc41824add66232446676.tar.bz2 chat-701d1ab638b23c24877fc41824add66232446676.zip |
Updating server dependancies (#5249)
Diffstat (limited to 'vendor/github.com/disintegration/imaging/histogram.go')
-rw-r--r-- | vendor/github.com/disintegration/imaging/histogram.go | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/vendor/github.com/disintegration/imaging/histogram.go b/vendor/github.com/disintegration/imaging/histogram.go new file mode 100644 index 000000000..aef333822 --- /dev/null +++ b/vendor/github.com/disintegration/imaging/histogram.go @@ -0,0 +1,43 @@ +package imaging + +import ( + "image" +) + +// Histogram returns a normalized histogram of an image. +// +// Resulting histogram is represented as an array of 256 floats, where +// histogram[i] is a probability of a pixel being of a particular luminance i. +func Histogram(img image.Image) [256]float64 { + src := toNRGBA(img) + width := src.Bounds().Max.X + height := src.Bounds().Max.Y + + var histogram [256]float64 + var total float64 + + if width == 0 || height == 0 { + return histogram + } + + for y := 0; y < height; y++ { + for x := 0; x < width; x++ { + i := y*src.Stride + x*4 + + r := src.Pix[i+0] + g := src.Pix[i+1] + b := src.Pix[i+2] + + var y float32 = 0.299*float32(r) + 0.587*float32(g) + 0.114*float32(b) + + histogram[int(y+0.5)]++ + total++ + } + } + + for i := 0; i < 256; i++ { + histogram[i] = histogram[i] / total + } + + return histogram +} |