maxhumber / gif Goto Github PK

Different gif.save() parameters seem to have no effect.

Code to reproduce (gif.save() call on line 118): https://gist.github.com/ddejohn/fa67039541bdb7e387c403fe32a65eb9

Different parameters, same gif produced

Here's an album of gifs produced with four different sets of parameters:

duration=100, unit="ms", between="frames"
duration=5, unit="ms", between="frames"
duration=1, unit="s", between="startend"
duration=10, unit="s", between="startend"

The only apparent difference is file size:

Good day. Very useful this library!

I do not know how it works internally, however I would like to know if there is a way to use it (and if possible, in what way) with the plotly.py library

Thank you, have a nice day.

Hi, using gif-22.5.0 for the first time...

macOS 12.4
python 3.9.12

Running example at Usage point in https://pypi.org/project/gif/

(.pepito) jose@MacBook-Air-2 keynote % python3 gif.py
Traceback (most recent call last):
  File "/Users/jose/Web/keynote/gif.py", line 3, in <module>
    import gif
  File "/Users/jose/Web/keynote/gif.py", line 9, in <module>
    gif.options.matplotlib["dpi"] = 300
AttributeError: partially initialized module 'gif' has no attribute 'options' (most likely due to a circular import)

I want to show a bar plot where bar for the next unit on x-axis appear one after the other and then stop once the last point is reached.
I managed to successfully create my bar plot and save the the gif, however the gif loops which I do not want.
Is there a way to repeat loops?

In trying to plot an audio signal stored in the array piano as a function of time t, in increments of 1000 elements, with various parts of the signal highlighted as the animation goes on with axvspan, I created the function:

@gif.frame
def plot_progression(T):
    #f, ax = plt.subplots(figsize=(6,4), dpi=100)
    plt.plot(t[:(T+1)*1000], piano[0][:(T+1)*1000], c="k", alpha=0.7)
    plt.xlabel("Time (seconds)")
    plt.ylabel("Amplitude (?)")
    plt.xlim([0,20])
    plt.ylim([-0.4, 0.4])
    if 1.8 < t[T] < 4.5:
        plt.axvspan(1.8, t[T], facecolor="Red", ls="--", lw=2.0, label=r"$C_{3}$", alpha=0.2)
    elif t[T] > 4.5:
        plt.axvspan(1.8, 4.5, facecolor="Red", ls="--", lw=2.0, label=r"$C_{3}$", alpha=0.2)
        plt.legend(fontsize="small")
    elif 5.5 < t[T] < 7.8:
        plt.axvspan(5.5, t[T], facecolor="Orange", ls="--", lw=2.0, label=r"$E_{3}$", alpha=0.2)
    elif t[T] > 7.8:
        plt.axvspan(5.5, 7.8, facecolor="Orange", ls="--", lw=2.0, label=r"$E_{3}$", alpha=0.2)
    elif 8.9 < t[T] < 11.2:
        plt.axvspan(8.9, t[T], facecolor="Green", ls="--", lw=2.0, label=r"$G_{3}$", alpha=0.2)
    elif t[T] > 11.2:
        plt.axvspan(8.9, 11.2, facecolor="Green", ls="--", lw=2.0, label=r"$G_{3}$", alpha=0.2)
    elif 12.2 < t[T] < 15.3:
        plt.axvspan(12.2, t[T], facecolor="Purple", ls="--", lw=2.0, label=r"$C_{maj}$", alpha=0.2)
    elif t[T] > 15.3:
        plt.axvspan(12.2, 15.3, facecolor="Purple", ls="--", lw=2.0, label=r"$C_{maj}$", alpha=0.2)

with the gif creation loop:

frames = []
for T in range(382):
    frame = plot_progression(T)
    frames.append(frame)
    del frame
    
gif.save(frames, "./audio_progression.gif", duration=45.4)

Problem is, none of the conditionals ever get triggered. All I get is the audio signal, no vspans or inclusion of the legend elements:

Also, is there any way to have the gif not loop? I know in gif.py the setting have loop=0 what do we set that to to get it to not loop? Can this be added as an argument to gif.save()?

Since the code uses indexes [0] and [1:] to take the first and then the rest of the elements of the list, I understand generators won't work here.

You could say the solution would be just converting the generator into a list, but for my use case (2500k frames @ 150 dpi) it takes a lot of memory to allocate the list. Actually, it might work the other way around.

I'd suggest something like:

def save(frames, path, duration=100):
    # iter() works for either lists and other iterators (such as generators)
    frames = iter(frames) 
    firstframe = next(frames)

    firstframe.save(
        path,
        save_all=True,
        append_images=frames,	# The first one was already read by next()
        optimize=True,
        duration=duration,
        loop=0,
    )

Any thoughts?

Hi! I have an idea about optimizing gif size:

from PIL import Image
from pathlib import Path
import numpy as np

# read list of pngs
paths = sorted(Path('.').glob('out*.png'))

# open pngs as numpy arrays
images = [np.array(Image.open(path)) for path in paths]

# stack the arrays into a single image
mega_img = Image.fromarray(np.hstack(images))

# reduce number of colors to 255, allowing for 0 to be transparent
mega_img = mega_img.quantize(colors=256 - 1, dither=0)

# append transparent color to the palette
palette = b'\xff\x00\xff' + mega_img.palette.getdata()[1]

# split arrays back
arrays = np.hsplit(np.array(mega_img), len(paths))
for array in arrays:
    # account for transparent color
    array += 1

prev_array = arrays[0]
for array in arrays[1:]:
    mask = array == prev_array
    prev_array = array.copy()
    # set unchanged pixels to transparent color
    array[mask] = 0

path = 'out.gif'
duration_ms = 200
images = [Image.fromarray(array) for array in arrays]

images[0].save(  # type: ignore
        path,
        save_all=True,
        append_images=images[1:],
        palette=palette,
        optimize=True,
        duration=duration_ms,
        disposal=0,
        loop=0,
        transparency=0,
        version='GIF89a',
    )

With this code my image sequence produced 176KiB gif instead of 3400KiB gif. The downside is that it is reasonably slower and uses at least 2x memory. Is there a place for this optimization technique in this library?

I would love some help with some more cool examples/

If you contribute one, I'll mail you a sticker 😍

Currently things happend in the global namespace. I think it would be very nice to be able to have separate objects for separate gifs, something like this:

my_gif = GifObj()

@my_gif.frame
def frame(i):
  ...

my_gif.save_img("my_gif.gif", frames=range(100))

I can try to draft a PR if you want.