61 lines
1.3 KiB
Go
61 lines
1.3 KiB
Go
package thumb
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import (
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"image"
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"image/color"
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"github.com/dustin/go-humanize"
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)
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// Byte size factors.
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const (
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KB = 1024
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MB = KB * 1024
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GB = MB * 1024
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)
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// Bytes represents memory usage in bytes.
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type Bytes uint64
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// KByte returns the size in kilobyte.
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func (b Bytes) KByte() float64 {
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return float64(b) / KB
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}
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// MByte returns the size in megabyte.
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func (b Bytes) MByte() float64 {
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return float64(b) / MB
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}
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// GByte returns the size in gigabyte.
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func (b Bytes) GByte() float64 {
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return float64(b) / GB
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}
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// String returns a human-readable memory usage string.
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func (b Bytes) String() string {
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return humanize.Bytes(uint64(b))
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}
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// MemSize returns the estimated size of the image in memory in bytes.
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func MemSize(img image.Image) Bytes {
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r := img.Bounds()
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pixels := r.Dx() * r.Dy()
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bytesPerPixel := 4
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// Image representation in a computer memory:
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// https://medium.com/@oleg.shipitko/what-does-stride-mean-in-image-processing-bba158a72bcd
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switch img.ColorModel() {
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case color.AlphaModel, color.GrayModel:
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bytesPerPixel = 1
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case color.Alpha16Model, color.Gray16Model:
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bytesPerPixel = 2
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case color.RGBAModel, color.NRGBAModel:
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bytesPerPixel = 4
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case color.RGBA64Model, color.NRGBA64Model:
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bytesPerPixel = 8
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}
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return Bytes(pixels * bytesPerPixel)
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}
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