Legacy ImageMagick Discussions Archive

Hello, I'm new to imagemagick, I was looking at ways to optimise a gif with a static background. I wondered if the first frame can be reused to save filesize - I thought perhaps using the dispose method.

Here's what I mean, I have a brick wall on the first frame, then a spinning ball on the following frames. I want the ball to spin on the brick wall background. Here is a version I created from a PNG sequence using dispose method 3 (keeping the previous image):

Here is the same gif generated using dispose method 1 (removing previous image)

I need the previous ball frames to dispose, keeping frame one. Is there a way to do this?

Many thanks

I don't understand what is in your PNG sequence, and I'm not sure what you want for the output. I guess you want the output to be a ball in various positions against a wall. And perhaps your PNG sequence is a wall with no ball, and balls in various positions with no wall but a transparent background.

If so, then the obvious method is to compose each of the ball images over the wall, in turn:

Code: Select all

magick wall.png NULL: balls*.png -compose over -layers composite -layers optimize out.gif

Perhaps there is a better way with "-dispose".

Thanks for your reply snibgo, hopefully this post will make it clearer.

The background is this, test_bg.png:

The testpngs directory is a transparent png sequence containing these images:

I almost got it working using this:

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convert -dispose none -delay 0 test_bg.png -dispose previous -delay 4 testpngs/*.png -loop 0 test.gif

This produced an amazingly small file size of 30k, but there is a pause on the first frame. This problem is referenced in the Docs here http://www.imagemagick.org/Usage/anim_basics/#cleared:

I have tried various Optimisation methods, but nothing comes close to the file size of 30k.

If this is impossible to get rid of the jolt, then I was thinking OptimizeTransparency sounded promising, but I worry I'm over complicating it.

Any further ideas appreciated. I'm using ImageMagick 7.0.8-3 on a Mac via Terminal

Thanks again

snibgo wrote: ↑2018-06-26T08:34:23-07:00 I don't understand what is in your PNG sequence, and I'm not sure what you want for the output. I guess you want the output to be a ball in various positions against a wall. And perhaps your PNG sequence is a wall with no ball, and balls in various positions with no wall but a transparent background.

If so, then the obvious method is to compose each of the ball images over the wall, in turn:
Code: Select all
magick wall.png NULL: balls*.png -compose over -layers composite -layers optimize out.gif
Perhaps there is a better way with "-dispose".

Please provide the two actual input images - the brick and the circling yellow dot gif.

bg image: https://imageshack.com/a/img922/926/d6c6V9.png
ball frames: https://imageshack.com/a/2Kko/1

Sorry the 49 images are separate, I couldn't find a reliable zip share site

It resizes to 160px width on output;

Code: Select all

convert -dispose none -delay 0 test_bg.png -dispose previous -delay 4 testpngs/*.png -scale 160 -loop 0 test.gif

fmw42 wrote: ↑2018-06-26T10:30:24-07:00 Please provide the two actual input images - the brick and the circling yellow dot gif.

Make your set of yellow dot images into an animated gif and see if that has the jolt. Make that work first. If it does not have a jolt, then upload the animated gif for the yellow balls or zip all the pngs and upload that. I do not want to try downloading all your separate yellow ball pngs.

Sure:

and bg again for reference:

fmw42 wrote: ↑2018-06-26T10:52:55-07:00 Make your set of yellow dot images into an animated gif and see if that has the jolt. Make that work first. If it does not have a jolt, then upload the animated gif for the yellow balls or zip all the pngs and upload that. I do not want to try downloading all your separate yellow ball pngs.

This command works fine for me in ImageMagick 6.9.10.2 Q16 Mac OSX.

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convert bricks.png null: \( yellow_dots.gif -coalesce \) -layers composite -layers optimize anim.gif

That works perfectly, thanks to both fmw42 & snibgo for your help

fmw42 wrote: ↑2018-06-26T15:43:11-07:00 This command works fine for me in ImageMagick 6.9.10.2 Q16 Mac OSX.
Code: Select all
convert bricks.png null: \( yellow_dots.gif -coalesce \) -layers composite -layers optimize anim.gif

Legacy ImageMagick Discussions Archive

Using dispose method to reuse background

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