Just thought I'd make a slight change. it's idiomatic to have a switch statement in this situation where there are multiple if statements, especially since only one variable is involved. I also made sure tests passed before submitting this pull request.

Since the resuting code that could be executed on each condition is only one line, I didn't think to place parentheses over the single statements, but let me know if that's what you prefer and I'll make the changes accordingly.

This will provide a much more simple interface, reduce the need to merge in default options, etc etc.

http://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis

Since []float64 is computed from reading samples anyway, allow direct generation by inputting []float64. Also add the option to retrieve the values used to compute a new waveform from a io.Reader, so that the same waveform can be quickly regenerated.

If possible, allow images to be generated, encoded, and directly streamed using io interfaces. This would enable images to be sent via HTTP as they are generated, etc.

Right now, image width is completely dependent on stream duration. In the future, it would be nice to be able to specify that the output image should be a certain width.

Hi, I'm trying to get []float64 from Compute() method of Waveform, but it returns an error of "audio: unknown format", is there anything that I did wrong?

myAgi := agi.New()
myAgi.Init(nil)

fd, err := syscall.Open("/dev/fd/3", syscall.O_RDWR, 0755)  // open file descriptor
if err != nil {
	myAgi.Verbose(err)
	return
}

buf := make([]byte, 1024)

for {
	n, err := syscall.Read(fd, buf)  // read streaming audio
	if n > 0 {
		br := bytes.NewReader(buf[:n])

		wav, err := waveform.New(br)
		if err != nil {
			myAgi.Verbose(err)
		}

		value, err := wav.Compute()
		if err != nil {
			myAgi.Verbose(err)  // got an error here
		}

		// futher proccesing with value
	}

	if err != nil {
		myAgi.Verbose(err)
		return
	}
} 

General changes:

• Consistent line breaks after 80 characters
• Heading levels (# for title and ## for sections)

LICENSE.md:

• Replace (C) with copyright symbol

README.md:

• Badges aren't part of the title anymore
• Small fixes (MIT Licensed to MIT licensed and show's to shows)
• Specify language for code snippets

Hi,

I'm using the latest commit of waveform: 6b28917edfbacd50bff4d58f951cf80499c952c4 and Go 1.11 on 64-bit Arch Linux.

After building waveform and copying test.wav to the cmd/waveform directory:

$ ls -al
.rw-r----- 1,0k afr 14 sep.  11:36 README.md
.rw-r-----  47M afr 14 sep.  11:40 test.wav
.rwxr-x--- 3,0M afr 14 sep.  11:36 waveform*
.rw-r----- 4,8k afr 14 sep.  11:36 waveform.go
.rw-r-----    0 afr 14 sep.  11:40 waveform.png
$ file test.wav
test.wav: RIFF (little-endian) data, WAVE audio

When attempting to create a .png image, I get an error message:

$ cat test.wav | ./waveform -x 5 -y 2 > waveform.png
panic: EOF

goroutine 1 [running]:
main.main()
        /home/afr/clones/waveform/cmd/waveform/waveform.go:127 +0xc9b

I tried with several different .wav files.

Line 127 in waveform.go is here.

this;

./waveform.a -resolution 1000 < wavTones.com.unregistred.sin_10Hz_-12dBFS_1s.wav > temp.png

(wav file from here; http://www.wavtones.com/functiongenerator.php github wont let me add wav files, but these both produce correct waveforms in audacity.)

produces this;

which is too big, -12db is 1/4 full scale.

and this, which is just full scale;

./waveform.a -resolution 1000 < wavTones.com.unregistred.sin_10Hz_0dBFS_1s.wav > temp.png

produces this? (completely white png)

when i generate with this;

img, err := waveform.Generate(out,waveform.Resolution(8000),bColor,fColor)

with a wave file with 8k samples per second, its fine, using 6MB memory in 0.01sec, but

img, err := waveform.Generate(out,waveform.Resolution(10000),bColor,fColor)

(ie when resolution slightly higher than the sample rate, )

i had to kill the process at 6GB mem usage.