Export Sprite Sheet - Difference between 'Trim Sprite' and 'Trim Cels'

[Gasparoken]

Trim Sprite: it will trim all frames with the same rectangle bounds x, y, w, h referred to the source size.

Trim Cels - will trim each ‘frame image’ to get a smaller sprite sheet, then the bounds of the trim rectangle will be unique for each frame referred to the source size (we can get smaller sprite sheets compared to ‘Trim Sprite’ ).

Example:
Source file 32x32, 2 frames: example.aseprite

Result of Export Sprite Sheet with ‘Trim Sprite’:

Look at ‘x, y, w, h’ of ‘spriteSourceSize’: same for the two frames

{ "frames": {
   "example 0.aseprite": {
    "frame": { "x": 0, "y": 0, "w": 26, "h": 11 },
    "rotated": false,
    "trimmed": true,
    "spriteSourceSize": { "x": 3, "y": 11, "w": 26, "h": 11 },
    "sourceSize": { "w": 32, "h": 32 },
    "duration": 100
   },
   "example 1.aseprite": {
    "frame": { "x": 26, "y": 0, "w": 26, "h": 11 },
    "rotated": false,
    "trimmed": true,
    "spriteSourceSize": { "x": 3, "y": 11, "w": 26, "h": 11 },
    "sourceSize": { "w": 32, "h": 32 },
    "duration": 100
   }
 }

Result of Export Sprite Sheet with ‘Trim Cels’:

Look at ‘x, y, w, h’ of ‘spriteSourceSize’: different for each frame.

{ "frames": {
   "example 0.aseprite": {
    "frame": { "x": 0, "y": 0, "w": 6, "h": 5 },
    "rotated": false,
    "trimmed": true,
    "spriteSourceSize": { "x": 3, "y": 11, "w": 6, "h": 5 },
    "sourceSize": { "w": 32, "h": 32 },
    "duration": 100
   },
   "example 1.aseprite": {
    "frame": { "x": 6, "y": 0, "w": 6, "h": 6 },
    "rotated": false,
    "trimmed": true,
    "spriteSourceSize": { "x": 23, "y": 16, "w": 6, "h": 6 },
    "sourceSize": { "w": 32, "h": 32 },
    "duration": 100
   }
 }

[Ethan_Buttazzi]

idk exacly whats happening here, but thr trim option in aseprite alredy takes all frames into account

[Gasparoken]

I write this topic to explain the difference between the two available options on Export Sprite Sheet dialog.
This topic was open to add information to the following issue at Aseprite repo: Trim Sprite option is ignored · Issue #3740 · aseprite/aseprite · GitHub
The artist thought the Trim Sprite option should result in a smaller ‘sourceSize’ on the json file (due to trim).