EaselJS and ImpactJS Support for Leshy SpriteSheet Animator

Posted by Doug Haber on 2013-06-16

Introduction

Leshy SpriteSheet Animator has been updated to support exporting animations for CreateJS / EaselJS and ImpactJS. This new update also fixes a few issues and cleans up some inconsistencies within the program and the save file formats. Old save file formats should still be compatible.

This post will discuss the new export features for ImpactJS and CreateJS and how to use them. It will also provide some documentation for the JSON file formats.

If you are new to Leshy Sprite Sheet Animator, please take a look at the blog post where it was introduced. You can also try it out with a demo sprite sheet here.

Launch Leshy Sprite Sheet Animator

New Exporters

In order to make this tool more useful for others I added exporters for CreateJS and ImpactJS. With each of these there is no one right way of producing the output format. I tried to choose a single clean way that was close to a way suggested in the documentation.

When the button is pushed for one of these, the current sprite sheet and all of its animations are converted to the requested format. A pop-up appears with an editable text area. Modifications may be made to the text there, and then it can be saved to a file, or just copy and pasted out of there.

Adding more formats is relatively easy. If there is another format that a large number of people would benefit from having supported, please suggest it in the comments below, and provide a link to the documentation or examples of how this would look.

CreateJS

The CreateJS exporter follows an example found in the SpriteSheet Class documentation. Frame lists are always written out in the long form, and the image asset is assumed to be in the current directory.

An issue I found with CreateJS is that it doesn't support specifying the speed for animations. There is a "frequency" parameter, but that seems to indicate how many ticks to show each frame. This means that the FPS setting of the Ticker will effect the correct frequency. In order to deal with this I added a "Ticker FPS" text input so that the FPS can be specified and the frequency can be correctly calculated. Clicking the "Apply" button will recreate all text with the new frequencies.

Another complication with CreateJS is that the frequencies have to be whole numbers. This means the granularity of possible speeds to express is limited, and at lower frame rates it is just not possible to specify speeds with much accuracy. The frequency values are rounded to the closest possible value for the Ticker FPS.

CreateJS users should be aware that animations will not necessarily run at the correct speed, even with this technique. If you specify 60 FPS and there is a frequency of 1, you may expect your animation to run at 60 FPS, but that will only be true so long as the user is really getting 60 FPS. If over one second they only can render 45 frames, then the animation will slow down. There are ways to work around and fix this, but they go beyond the scope of this post.

I am not experienced with CreateJS. If anyone has any feedback on my observations, or ideas on how this can be better handled in this application, please let me know.

Sample CreateJS Output

Here is sample output for the demo "kitty_hula.png" at 60 frames per second:
var data = {
     images: [ "kitty_hula.png" ],
     frames: { width: 61, height: 81 },
     animations: {
          "all": { frames: [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 ], frequency: 4 },
          "point_left": { frames: [ 15, 16, 17, 18, 19, 18, 17, 16 ], frequency: 10 },
          "wobble": { frames: [ 0, 1, 2, 3, 4, 3, 2, 1 ], frequency: 8 },
          "point_right": { frames: [ 21, 22, 23, 24, 23, 22 ], frequency: 10 }
     }
};

var spriteSheet = new createjs.SpriteSheet(data);
var animation = new createjs.BitmapAnimation(spriteSheet);

Example CreateJS Usage

Here is a working example that shows how this may be used. Please look at this as an example of how this may be done, and not necessarily an example of how it should be done within your application or game.
function init() {
    // ***** This is the beginning of the generated code
    // ***** from Leshy SpriteSheet Animator
    var data = {
        images: [ "kitty_hula.png" ],
        frames: { width: 61, height: 81 },
        animations: {
            "all": { frames: [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 ], frequency: 4
 },
            "point_left": { frames: [ 15, 16, 17, 18, 19, 18, 17, 16 ], frequency: 10 },
            "wobble": { frames: [ 0, 1, 2, 3, 4, 3, 2, 1 ], frequency: 8 },
            "point_right": { frames: [ 21, 22, 23, 24, 23, 22 ], frequency: 10 }
        }
    };

    var spriteSheet = new createjs.SpriteSheet(data);
    var animation = new createjs.BitmapAnimation(spriteSheet);

    // ***** Everything below this point is demo code

    // Create a stage using a canvas already on the page with the id "canvas"
    var stage = new createjs.Stage("canvas");

    animation.gotoAndPlay("all"); // Run the default animation
    stage.addChild(animation); // Add the animation to the stage

    createjs.Ticker.useRAF = true; // Use request animation frame

    // Set the framerate to 60.  This must match the animation's
    // export in order for the speeds to be correct
    createjs.Ticker.setFPS(60);

    createjs.Ticker.addEventListener("tick", function () { // Every tick, update the stage
        stage.update();
    });
}

window.onload = init;

ImpactJS

The ImpactJS exporter uses the animation documentation as a guide. The image asset is assumed to be in the current directory.

It appears that in ImpactJS, animations are returned as objects, and there is no default storage of them, unlike in CreateJS. To work around this, the exporter creates an "animations" object where each key is the name of an animation, and each value is the associated animation object. So, with the export, if you have an animation named "walk", you would access it with "animations['walk']".

Animation names are specified as strings. I have done this so that (as long as usage is consistent) there are no issues with minifiers that could arise in some situations, such as if the animations are used as external data.

The animation speeds in ImpactJS are specified as time per frame in seconds. The exporter rounds this out to 4 decimal places.

I don't have a license for ImpactJS, so this is all untested, and I don't have a working example. It follows the documentation, so I'd expect it to work. If anyone with a license can verify this works, I would appreciate it.

UPDATE: The ImpactJS exporter now also supports the animation-importer plugin for ImpactJS. This export format makes it possible to drop in the exported animations without making any other changes. For more details, see the blog post about this update.

Sample ImpactJS Output
var animSheet = new ig.AnimationSheet("kitty_hula.png", 61, 81);
var animations = {
     "all": new ig.Animation(animSheet, 0.0625, [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 ]),
     "point_left": new ig.Animation(animSheet, 0.1667, [ 15, 16, 17, 18, 19, 18, 17, 16 ]),
     "wobble": new ig.Animation(animSheet, 0.125, [ 0, 1, 2, 3, 4, 3, 2, 1 ]),
     "point_right": new ig.Animation(animSheet, 0.1667, [ 21, 22, 23, 24, 23, 22 ])
};

Standard Export JSON Formats

There are two types of JSON files that can be exported and imported into this program. There are animation files that contain a sprite sheet and all of its animations. These are created from the "Export Animations" button. There also are project files that include the full state of the application including all sprite sheets, animations, images, and settings. These are used for saving and loading the state, and they are created with the "Export All" button.

Animation JSON Files

Example file:
{
  "note": "Leshy Sprite Sheet Animator v1.0.1",
  "type": "lss_animations",
  "animations": {
    "all": {
      "frames": "0:24:1",
      "fps": 16
    },
    "point_left": {
      "frames": "15:19:16",
      "fps": 6
    },
    "wobble": {
      "frames": "0:4:1",
      "fps": 8
    },
    "point_right": {
      "frames": "21:24:22",
      "fps": 6
    }
  },
  "height": 81,
  "width": 61
}

Animation JSON File Reference:

Name Type Description
note String This is an string containing the application name and version. If the format changes in future versions, this string could help provide for backwards compatibility. The string for the current version is "Leshy SpriteSheet Animator v1.0.1"
type String This is an identifier of the type of file. When a JSON file is dropped into the application, it looks at this to decide what to do with it. Animation files use the type "lss_animations".
animations Object This is an object where each key is the name of animation, and each value is another object with a parameter for "frames" and "fps". For details, see the "Animation Object" section below.
height Number The height of each frame in the sprite sheet, in pixels. The number of rows will automatically be determined based on this number and the image size.
width Number The width of each frame in the sprite sheet, in pixels. The number of columns will automatically be determined based on this number and the image size.

Animation Object:

Name Type Description
Frames String This is the frame list. For a full reference to the legal values here, see the initial blog post.
FPS Number The number of frames per second for the animation to run at. This determines the amount of time each frame is shown before switching to the next frame. 1 / FPS = Time per frame in seconds.

Project JSON Files

Example File:
{
  "note": "Leshy Sprite Sheet Animator v1.0.1",
  "type": "lss_spriteSheets",
  "animationShowOutline": false,
  "animationShowBackground": false,
  "animationColor": "#004e97",
  "animationPadding": 20,
  "animationScale": 3.5,
  "spriteSheetShowOutline": true,
  "spriteSheetShowLabels": true,
  "spriteSheetShowBackground": false,
  "spriteSheetBackgroundColor": "#ffffff",
  "currentSpriteSheet": "kitty_hula.png",
  "currentTab": "animation",
  "spriteSheets": {
    "kitty_hula.png": {
      "animations": {
        "all": {
          "frames": "0:24:1",
          "fps": 16
        },
        "point_left": {
          "frames": "15:19:16",
          "fps": 6
        },
        "wobble": {
          "frames": "0:4:1",
          "fps": 8
        },
        "point_right": {
          "frames": "21:24:22",
          "fps": 6
        }
      },
      "height": 81,
      "width": 61,
      "img": "data:image\/png;base64,iVBOR...[base64.image.file]...",
      "currentAnimation": "all"
    },
    "fire.png": {
      "animations": {
        "normal": {
          "frames": "*",
          "fps": 20
        },
        "slow": {
          "frames": "*",
          "fps": 8
        },
        "reverse": {
          "frames": "*:0",
          "fps": 20
        }
      },
      "height": 96,
      "width": 48,
      "img": "data:image\/png;base64,iVBOR...[base64.image.file]...",
      "currentAnimation": "normal"
    }
  }
}

Project JSON File Reference:

Name Type Description
note String This is an string containing the application name and version. If the format changes in future versions, this string could help provide for backwards compatibility. The string for the current version is "Leshy SpriteSheet Animator v1.0"
type String This is an identifier of the type of file. When a JSON file is dropped into the application, it looks at this to decide what to do with it. The string for project files is "lss_spriteSheets"
animationShowOutline Boolean This is the "Show Outline" setting in the "Animation" tab. When true, an outline is drawn around the rendered frame.
animationShowBackground Boolean This is the "Checkered BG" setting in the "Animation" tab. When false, a checkered background is drawn. When true, a solid color background is drawn using the color from the "animationColor" attribute.
animationColor Color String This is the "BG Color" setting in the "Animation" tab. When the "animationShowBackground" attribute is false, this determines the color to be used for drawing a solid color background.
animationPadding Number This is the "Padding" setting in the "Animation" tab. It specifies the minimum allowed vertical padding in pixels.
animationScale Number This is the "Scale" setting in the "Animation" tab. It specifies how much to scale the animation preview. It is a multiplier against the default size, so 1 is 100%, 2 is 200%, and 0.5 would be 50%.
spriteSheetShowOutline Boolean This is the "Show Outline" setting in the "SpriteSheet" tab. When true, an outline is drawn around each frame when viewing the sprite sheet.
spriteSheetShowLabels Boolean This is the "Show Labels" setting in the "SpriteSheet" tab. When true, frame labels are drawn for each frame showing the frames numeric and grid coordinates.
spriteSheetShowBackground Number This is the "Checkered BG" setting in the "SpriteSheet" tab. When false, a checkered background is drawn behind the sprite sheet. When true, a solid color is drawn in the color specified by the "spriteSheetShowBackgroundColor" attribute.
spriteSheetShowBackgroundColor Color String This is the "BG Color" setting in the "SpriteSheet" tab. When "spriteSheetShowBackground" is true, a solid color background is drawn using this color.
currentSpriteSheet String This is the name of the sprite sheet to be loaded when this file is opened.
currentTab String This is the name of the current tab to have open when this file is opened. It can be either "Animation" or "SpriteSheet".
spriteSheets Object This object contains a key for each sprite sheet. The key is the name of the file, and the value is an object that is very similar to the Animation JSON File. That object contains a list of animations along with their framelist and speed, as well as size information. There are two additional fields not found in a normal Animation JSON File:

  • img - This is a base 64 encoded data uri of the image file.
  • currentAnimation - This contains the name of the current animation, so that the application knows which animation to default to when the sprite sheet is opened.




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