Lottie: Animation Segment(Marker) Support

[fall2019]

issue: #2044

[hermet]

@fall2019, could you please squash your unnecessary commits to the one?

[fall2019]

Okay. I usually use squash on merge option. Will try to squash later.

[fall2019]

Squashed all commits into one.

[tinyjin]

Hello, Thank you so much for the efforts.
We'd love to have your patches.

Please check these comments:

1. Conflict Resolution

• src/loaders/lottie/tvgLottieLoader.h currently has a merge conflict.
• Please ensure that the patch is conflict-free before merging.

2. Enhance Commit Message Clarity

• The current message simply states "POC"
• It would be beneficial to provide a more descriptive message that outlines the purpose of these changes.
• We strongly recommend referring to this guidance for composing meaningful commit messages.

3. Improve Commit Description Formatting:

• The commit description appears unclear.
• It seems to be just squashed without tidying the explanations, there are a lot of typos or unnecessary texts.
• Please check again the description is clear and concise.
  

[fall2019]

Okay. Thanks for reviewing and your article is really helpful. Will resolve the comments later.

[hermet]

Thanks for your contribution, quickly examined the API design.

[fall2019]

You're welcome. Will try to resolve soon.

[fall2019]

Resolved all comments.

[fall2019]

Alright. Resolved.

[hermet]

Reviewed "Animation Segment(Marker) Support" commit. It looks almost there. Thanks,

[hermet]

@fall2019 One more, please add yourself "https://github.com/thorvg/thorvg/blob/main/AUTHORS" please.

[fall2019]

Thanks. Resolved all comments.

[tinyjin]

Please check comments.

[tinyjin]

@hermet
I've tested segment API in various suites, seems nicely working. (some minor consideration -> commented)

Here, I wanna make sure two things.

1. Unit test
Should we include unit test for marker & segment in this patch? Otherwise, I can also add all cases I've checked into testLottie.cpp and capiLottie.cpp right after merging.

2. Support marker comment in JSON objects.

"markers": [
    { "tm": 0, "cm": "{\\"name\\":\\"bird\\"}", "dr": 22 },
    { "tm": 22, "cm": "{\\"name\\":\\"explosion\\"}", "dr": 11 },
    { "tm": 33, "cm": "{\\"name\\":\\"feather\\"}", "dr": 77 }
]

This is also from RFC, the markers[].cm could be JSON string. Do you think it must be in this patch? I think we can gradually support this case in next patch.

[hermet]

1. Unit test
Should we include unit test for marker & segment in this patch? Otherwise, I can also add all cases I've checked into testLottie.cpp and capiLottie.cpp right after merging.

@tinyjin Yes, It would be better to perform unit testing, but it's not mandatory in this PR.

@fall2019 Since on this topic, Returning the list of marker names will be essential, so users can inquire about the available markers in the animation. Probably, like this:

uint32_t LottieAnimation::markerCnt();  //return the marker count
const char* LottieAnimation::markers(uint32_t idx); //return the marker name by a given index.

The items(unit test and apis) mentioned above are not the main focus at this point but will become essential eventually. Therefore, it's up to you. If you'd like to include them, please update the PR accordingly. Thanks.

2. Support marker comment in JSON objects.

"markers": [
    { "tm": 0, "cm": "{\\"name\\":\\"bird\\"}", "dr": 22 },
    { "tm": 22, "cm": "{\\"name\\":\\"explosion\\"}", "dr": 11 },
    { "tm": 33, "cm": "{\\"name\\":\\"feather\\"}", "dr": 77 }
]

This is also from RFC, the markers[].cm could be JSON string. Do you think it must be in this patch? I think we can gradually support this case in next patch.

@tinyjin No, it shouldn't be.

[hermet]

Reviewed "Add example for Animation Segment(Marker)"

[fall2019]

Add api
uint32_t LottieAnimation::markerCnt(); //return the marker count const char* LottieAnimation::markers(uint32_t idx); //return the marker name by a given index.

Resolved all comments.

[tinyjin]

@fall2019. So far pretty good.
It's around the corner. I'm going to soon wrap up this patch by my side.

Thanks.

[fall2019]

Okay. On your side.

[tinyjin]

#2164