README
¶
HDR - High Dynamic Range
HDR is a library that handles RAW image format written with Golang. Here some rendering examples.
It aims to provide tools to read HDR files and convert it to a LDR (Low Dynamic Range, aka PNG/JPEG/etc.) in an image.Image object.
Documentations:
Supported codecs (file formats)
- Radiance RGBE/XYZE
- PFM, Portable FloatMap file format
- TIFF using mdouchement/tiff
- CRAD, homemade HDR file format
Supported tone mapping operators
Read this documentation to find what TMO use.
Read this documentation to understand what is a TMO.
- Linear
- Logarithmic
- Drago '03 - Adaptive logarithmic mapping for displaying high contrast scenes
- Durand - Fast bilateral filtering for the display of high-dynamic-range images
- Reinhard '05 - Photographic tone reproduction for digital images
- Playing with parameters could provide better rendering
- Custom Reinhard '05
- Rendering looks like a JPEG photo taken with a smartphone
- iCAM06 - A refined image appearance model for HDR image rendering
Usage
go get github.com/mdouchement/hdr
package main
import (
"fmt"
"image"
"image/png"
"os"
"runtime"
"time"
"github.com/mdouchement/hdr"
_ "github.com/mdouchement/hdr/codec/rgbe"
"github.com/mdouchement/hdr/tmo"
)
// Samples:
//
// http://www.anyhere.com/gward/hdrenc/pages/originals.html
// http://resources.mpi-inf.mpg.de/tmo/logmap/ (High Contrast Scenes)
var (
// input = "/Users/mdouchement/tmp/hdr/memorial_o876.hdr"
// input = "/Users/mdouchement/tmp/hdr/MtTamWest_o281.hdr"
// input = "/Users/mdouchement/tmp/hdr/rend02_oC95.hdr"
// input = "/Users/mdouchement/tmp/hdr/Tree_oAC1.hdr"
input = "/Users/mdouchement/tmp/hdr/Apartment_float_o15C.hdr"
output = "/Users/mdouchement/tmp/hdr/output.png"
)
func main() {
fmt.Printf("Using %d CPUs\n", runtime.NumCPU())
fi, err := os.Open(input)
check(err)
defer fi.Close()
start := time.Now()
m, fname, err := image.Decode(fi)
check(err)
fmt.Printf("Read image (%s) took %v\n", fname, time.Since(start))
if hdrm, ok := m.(hdr.Image); ok {
startTMO := time.Now()
// t := tmo.NewLinear(hdrm)
// t := tmo.NewLogarithmic(hdrm)
// t := tmo.NewDefaultDrago03(hdrm)
// t := tmo.NewDefaultDurand(hdrm)
// t := tmo.NewDefaultCustomReinhard05(hdrm)
t := tmo.NewDefaultReinhard05(hdrm)
// t := tmo.NewDefaultICam06(hdrm)
m = t.Perform()
fmt.Println("Apply TMO took", time.Since(startTMO))
}
fo, err := os.Create(output)
check(err)
png.Encode(fo, m)
fmt.Println("Total", time.Since(start))
}
func check(err error) {
if err != nil {
panic(err)
}
}
HDR Tools
https://github.com/mdouchement/hdrtool
License
MIT
Implementing a TMO
A TMO must implement tmo.ToneMappingOperator:
type ToneMappingOperator interface {
// Perform runs the TMO mapping.
Perform() image.Image
}
Implementing an image codec
- Reader
// DecodeConfig returns the color model and dimensions of a PFM image without
// decoding the entire image.
func DecodeConfig(r io.Reader) (image.Config, error) {
// ...
return m, err
}
// Decode reads a HDR image from r and returns an image.Image.
func Decode(r io.Reader) (img image.Image, err error) {
// ...
return
}
func init() {
// Register the format in the official lib.
// https://golang.org/pkg/image/#RegisterFormat
image.RegisterFormat("format-name", "magic-code", Decode, DecodeConfig)
}
- Writer
// Encode writes the Image m to w in PFM format.
func Encode(w io.Writer, m hdr.Image) error {
return nil
}
Contributing
All PRs are welcome. If you implement a TMO or an image codec in a dedicated repository, please tell me in order to link it in this readme.
- Fork it
- Create your feature branch (git checkout -b my-new-feature)
- Commit your changes (git commit -am 'Add some feature')
- Push to the branch (git push origin my-new-feature)
- Create new Pull Request
As possible, run the following commands to format and lint the code:
# Format
find . -name '*.go' -not -path './vendor*' -exec gofmt -s -w {} \;
# Lint
golangci-lint run -c .golangci.yml
Documentation
¶
Index ¶
- func Split(x1, y1, x2, y2, n int) []image.Rectangle
- func SplitWithRectangle(r image.Rectangle, n int) []image.Rectangle
- type Image
- type ImageSet
- type LMSCAT02w
- type LMSHPEw
- type RGB
- func (p *RGB) At(x, y int) color.Color
- func (p *RGB) Bounds() image.Rectangle
- func (p *RGB) ColorModel() color.Model
- func (p *RGB) HDRAt(x, y int) hdrcolor.Color
- func (p *RGB) PixOffset(x, y int) int
- func (p *RGB) RGBAt(x, y int) hdrcolor.RGB
- func (p *RGB) Set(x, y int, c color.Color)
- func (p *RGB) SetRGB(x, y int, c hdrcolor.RGB)
- func (p *RGB) Size() int
- type RGB64
- func (p *RGB64) At(x, y int) color.Color
- func (p *RGB64) Bounds() image.Rectangle
- func (p *RGB64) ColorModel() color.Model
- func (p *RGB64) HDRAt(x, y int) hdrcolor.Color
- func (p *RGB64) PixOffset(x, y int) int
- func (p *RGB64) RGBAt(x, y int) hdrcolor.RGB
- func (p *RGB64) Set(x, y int, c color.Color)
- func (p *RGB64) SetRGB(x, y int, c hdrcolor.RGB)
- func (p *RGB64) Size() int
- type XYZ
- func (p *XYZ) At(x, y int) color.Color
- func (p *XYZ) Bounds() image.Rectangle
- func (p *XYZ) ColorModel() color.Model
- func (p *XYZ) HDRAt(x, y int) hdrcolor.Color
- func (p *XYZ) PixOffset(x, y int) int
- func (p *XYZ) Set(x, y int, c color.Color)
- func (p *XYZ) SetXYZ(x, y int, c hdrcolor.XYZ)
- func (p *XYZ) Size() int
- func (p *XYZ) XYZAt(x, y int) hdrcolor.XYZ
- type XYZ64
- func (p *XYZ64) At(x, y int) color.Color
- func (p *XYZ64) Bounds() image.Rectangle
- func (p *XYZ64) ColorModel() color.Model
- func (p *XYZ64) HDRAt(x, y int) hdrcolor.Color
- func (p *XYZ64) PixOffset(x, y int) int
- func (p *XYZ64) Set(x, y int, c color.Color)
- func (p *XYZ64) SetXYZ(x, y int, c hdrcolor.XYZ)
- func (p *XYZ64) Size() int
- func (p *XYZ64) XYZAt(x, y int) hdrcolor.XYZ
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Image ¶
type Image interface {
image.Image
// HDRAt returns the HDR pixel color at given coordinates.
HDRAt(x, y int) hdrcolor.Color
// Size returns the number of pixels.
Size() int
}
Image is a finite rectangular grid of hdrcolor.Color values taken from a color model.
type LMSCAT02w ¶
type LMSCAT02w struct {
Image
}
A LMSCAT02w wrapper hollows to get pixels in LMS-space using CIE CAT02 matrix. https://en.wikipedia.org/wiki/CIECAM02#Chromatic_adaptation
func NewLMSCAT02w ¶
NewLMSCAT02w instanciates a new LMSCAT02w wrapper.
type LMSHPEw ¶
type LMSHPEw struct {
Image
}
A LMSHPEw wrapper hollows to get pixels in LMS-space using Hunt-Pointer-Estevez matrix. https://en.wikipedia.org/wiki/LMS_color_space
type RGB ¶
type RGB struct {
// Pix holds the image's pixels, in R, G, B order. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8].
Pix []float32
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect image.Rectangle
}
RGB is an in-memory 32 bits floating points image whose At method returns hdrcolor.RGB values.
func (*RGB) PixOffset ¶
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
type RGB64 ¶
type RGB64 struct {
// Pix holds the image's pixels, in R, G, B order. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8].
Pix []float64
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect image.Rectangle
}
RGB64 is an in-memory 64 bits floating points image whose At method returns hdrcolor.RGB values.
func (*RGB64) PixOffset ¶
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
type XYZ ¶
type XYZ struct {
// Pix holds the image's pixels, in X, Y and Z order. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8].
Pix []float32
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect image.Rectangle
}
XYZ is an in-memory 32 bits floating points image whose At method returns hdrcolor.XYZ values.
func (*XYZ) PixOffset ¶
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
type XYZ64 ¶
type XYZ64 struct {
// Pix holds the image's pixels, in X, Y and Z order. The pixel at
// (x, y) starts at Pix[(y-Rect.Min.Y)*Stride + (x-Rect.Min.X)*8].
Pix []float64
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect image.Rectangle
}
XYZ64 is an in-memory 64 bits floating points image whose At method returns hdrcolor.XYZ values.
func (*XYZ64) PixOffset ¶
PixOffset returns the index of the first element of Pix that corresponds to the pixel at (x, y).
Source Files
Directories