This file sourced from ASEPRITE https://github.com/aseprite/aseprite/blob/main/docs/ase-file-specs.md # Aseprite File Format (.ase/.aseprite) Specifications 1. [References](#references) 2. [Introduction](#introduction) 3. [Header](#header) 4. [Frames](#frames) 5. [Chunk Types](#chunk-types) 6. [Notes](#notes) 7. [File Format Changes](#file-format-changes) ## References ASE files use Intel (little-endian) byte order. * `BYTE`: An 8-bit unsigned integer value * `WORD`: A 16-bit unsigned integer value * `SHORT`: A 16-bit signed integer value * `DWORD`: A 32-bit unsigned integer value * `LONG`: A 32-bit signed integer value * `FIXED`: A 32-bit fixed point (16.16) value * `FLOAT`: A 32-bit single-precision value * `DOUBLE`: A 64-bit double-precision value * `QWORD`: A 64-bit unsigned integer value * `LONG64`: A 64-bit signed integer value * `BYTE[n]`: "n" bytes. * `STRING`: - `WORD`: string length (number of bytes) - `BYTE[length]`: characters (in UTF-8) The `'\0'` character is not included. * `POINT`: - `LONG`: X coordinate value - `LONG`: Y coordinate value * `SIZE`: - `LONG`: Width value - `LONG`: Height value * `RECT`: - `POINT`: Origin coordinates - `SIZE`: Rectangle size * `PIXEL`: One pixel, depending on the image pixel format: - **RGBA**: `BYTE[4]`, each pixel have 4 bytes in this order Red, Green, Blue, Alpha. - **Grayscale**: `BYTE[2]`, each pixel have 2 bytes in the order Value, Alpha. - **Indexed**: `BYTE`, each pixel uses 1 byte (the index). * `TILE`: **Tilemaps**: Each tile can be a 8-bit (`BYTE`), 16-bit (`WORD`), or 32-bit (`DWORD`) value and there are masks related to the meaning of each bit. * `UUID`: A Universally Unique Identifier stored as `BYTE[16]`. ## Introduction The format is much like FLI/FLC files, but with different magic number and differents chunks. Also, the color depth can be 8, 16 or 32 for Indexed, Grayscale and RGB respectively, and images are compressed images with zlib. Color palettes are in FLI color chunks (it could be type=11 or type=4). For color depths more than 8bpp, palettes are optional. To read the sprite: * Read the [ASE header](#header) * For each frame do (how many frames? the ASE header has that information): + Read the [frame header](#frames) + For each chunk in this frame (how many chunks? the frame header has that information) - Read the chunk (it should be layer information, a cel or a palette) ## Header A 128-byte header (same as FLC/FLI header, but with other magic number): DWORD File size WORD Magic number (0xA5E0) WORD Frames WORD Width in pixels WORD Height in pixels WORD Color depth (bits per pixel) 32 bpp = RGBA 16 bpp = Grayscale 8 bpp = Indexed DWORD Flags: 1 = Layer opacity has valid value WORD Speed (milliseconds between frame, like in FLC files) DEPRECATED: You should use the frame duration field from each frame header DWORD Set be 0 DWORD Set be 0 BYTE Palette entry (index) which represent transparent color in all non-background layers (only for Indexed sprites). BYTE[3] Ignore these bytes WORD Number of colors (0 means 256 for old sprites) BYTE Pixel width (pixel ratio is "pixel width/pixel height"). If this or pixel height field is zero, pixel ratio is 1:1 BYTE Pixel height SHORT X position of the grid SHORT Y position of the grid WORD Grid width (zero if there is no grid, grid size is 16x16 on Aseprite by default) WORD Grid height (zero if there is no grid) BYTE[84] For future (set to zero) ## Frames After the header come the "frames" data. Each frame has this little header of 16 bytes: DWORD Bytes in this frame WORD Magic number (always 0xF1FA) WORD Old field which specifies the number of "chunks" in this frame. If this value is 0xFFFF, we might have more chunks to read in this frame (so we have to use the new field) WORD Frame duration (in milliseconds) BYTE[2] For future (set to zero) DWORD New field which specifies the number of "chunks" in this frame (if this is 0, use the old field) Then each chunk format is: DWORD Chunk size WORD Chunk type BYTE[] Chunk data The chunk size includes the DWORD of the size itself, and the WORD of the chunk type, so a chunk size must be equal or greater than 6 bytes at least. ## Chunk Types ### Old palette chunk (0x0004) Ignore this chunk if you find the new palette chunk (0x2019). Aseprite v1.1 saves both chunks (0x0004 and 0x2019) just for backward compatibility. Aseprite v1.3.5 writes this chunk if the palette doesn't have alpha channel and contains 256 colors or less (because this chunk is smaller), in other case the new palette chunk (0x2019) will be used (and the old one is not saved anymore). WORD Number of packets + For each packet BYTE Number of palette entries to skip from the last packet (start from 0) BYTE Number of colors in the packet (0 means 256) + For each color in the packet BYTE Red (0-255) BYTE Green (0-255) BYTE Blue (0-255) ### Old palette chunk (0x0011) Ignore this chunk if you find the new palette chunk (0x2019) WORD Number of packets + For each packet BYTE Number of palette entries to skip from the last packet (start from 0) BYTE Number of colors in the packet (0 means 256) + For each color in the packet BYTE Red (0-63) BYTE Green (0-63) BYTE Blue (0-63) ### Layer Chunk (0x2004) In the first frame should be a set of layer chunks to determine the entire layers layout: WORD Flags: 1 = Visible 2 = Editable 4 = Lock movement 8 = Background 16 = Prefer linked cels 32 = The layer group should be displayed collapsed 64 = The layer is a reference layer WORD Layer type 0 = Normal (image) layer 1 = Group 2 = Tilemap WORD Layer child level (see NOTE.1) WORD Default layer width in pixels (ignored) WORD Default layer height in pixels (ignored) WORD Blend mode (always 0 for layer set) Normal = 0 Multiply = 1 Screen = 2 Overlay = 3 Darken = 4 Lighten = 5 Color Dodge = 6 Color Burn = 7 Hard Light = 8 Soft Light = 9 Difference = 10 Exclusion = 11 Hue = 12 Saturation = 13 Color = 14 Luminosity = 15 Addition = 16 Subtract = 17 Divide = 18 BYTE Opacity Note: valid only if file header flags field has bit 1 set BYTE[3] For future (set to zero) STRING Layer name + If layer type = 2 DWORD Tileset index ### Cel Chunk (0x2005) This chunk determine where to put a cel in the specified layer/frame. WORD Layer index (see NOTE.2) SHORT X position SHORT Y position BYTE Opacity level WORD Cel Type 0 - Raw Image Data (unused, compressed image is preferred) 1 - Linked Cel 2 - Compressed Image 3 - Compressed Tilemap SHORT Z-Index (see NOTE.5) 0 = default layer ordering +N = show this cel N layers later -N = show this cel N layers back BYTE[5] For future (set to zero) + For cel type = 0 (Raw Image Data) WORD Width in pixels WORD Height in pixels PIXEL[] Raw pixel data: row by row from top to bottom, for each scanline read pixels from left to right. + For cel type = 1 (Linked Cel) WORD Frame position to link with + For cel type = 2 (Compressed Image) WORD Width in pixels WORD Height in pixels PIXEL[] "Raw Cel" data compressed with ZLIB method (see NOTE.3) + For cel type = 3 (Compressed Tilemap) WORD Width in number of tiles WORD Height in number of tiles WORD Bits per tile (at the moment it's always 32-bit per tile) DWORD Bitmask for tile ID (e.g. 0x1fffffff for 32-bit tiles) DWORD Bitmask for X flip DWORD Bitmask for Y flip DWORD Bitmask for diagonal flip (swap X/Y axis) BYTE[10] Reserved TILE[] Row by row, from top to bottom tile by tile compressed with ZLIB method (see NOTE.3) ### Cel Extra Chunk (0x2006) Adds extra information to the latest read cel. DWORD Flags (set to zero) 1 = Precise bounds are set FIXED Precise X position FIXED Precise Y position FIXED Width of the cel in the sprite (scaled in real-time) FIXED Height of the cel in the sprite BYTE[16] For future use (set to zero) ### Color Profile Chunk (0x2007) Color profile for RGB or grayscale values. WORD Type 0 - no color profile (as in old .aseprite files) 1 - use sRGB 2 - use the embedded ICC profile WORD Flags 1 - use special fixed gamma FIXED Fixed gamma (1.0 = linear) Note: The gamma in sRGB is 2.2 in overall but it doesn't use this fixed gamma, because sRGB uses different gamma sections (linear and non-linear). If sRGB is specified with a fixed gamma = 1.0, it means that this is Linear sRGB. BYTE[8] Reserved (set to zero) + If type = ICC: DWORD ICC profile data length BYTE[] ICC profile data. More info: http://www.color.org/ICC1V42.pdf ### External Files Chunk (0x2008) A list of external files linked with this file can be found in the first frame. It might be used to reference external palettes, tilesets, or extensions that make use of extended properties. DWORD Number of entries BYTE[8] Reserved (set to zero) + For each entry DWORD Entry ID (this ID is referenced by tilesets, palettes, or extended properties) BYTE Type 0 - External palette 1 - External tileset 2 - Extension name for properties 3 - Extension name for tile management (can exist one per sprite) BYTE[7] Reserved (set to zero) STRING External file name or extension ID (see NOTE.4) ### Mask Chunk (0x2016) DEPRECATED SHORT X position SHORT Y position WORD Width WORD Height BYTE[8] For future (set to zero) STRING Mask name BYTE[] Bit map data (size = height*((width+7)/8)) Each byte contains 8 pixels (the leftmost pixels are packed into the high order bits) ### Path Chunk (0x2017) Never used. ### Tags Chunk (0x2018) After the tags chunk, you can write one user data chunk for each tag. E.g. if there are 10 tags, you can then write 10 user data chunks one for each tag. WORD Number of tags BYTE[8] For future (set to zero) + For each tag WORD From frame WORD To frame BYTE Loop animation direction 0 = Forward 1 = Reverse 2 = Ping-pong 3 = Ping-pong Reverse WORD Repeat N times. Play this animation section N times: 0 = Doesn't specify (plays infinite in UI, once on export, for ping-pong it plays once in each direction) 1 = Plays once (for ping-pong, it plays just in one direction) 2 = Plays twice (for ping-pong, it plays once in one direction, and once in reverse) n = Plays N times BYTE[6] For future (set to zero) BYTE[3] RGB values of the tag color Deprecated, used only for backward compatibility with Aseprite v1.2.x The color of the tag is the one in the user data field following the tags chunk BYTE Extra byte (zero) STRING Tag name ### Palette Chunk (0x2019) DWORD New palette size (total number of entries) DWORD First color index to change DWORD Last color index to change BYTE[8] For future (set to zero) + For each palette entry in [from,to] range (to-from+1 entries) WORD Entry flags: 1 = Has name BYTE Red (0-255) BYTE Green (0-255) BYTE Blue (0-255) BYTE Alpha (0-255) + If has name bit in entry flags STRING Color name ### User Data Chunk (0x2020) Specifies the user data (color/text/properties) to be associated with the last read chunk/object. E.g. If the last chunk we've read is a layer and then this chunk appears, this user data belongs to that layer, if we've read a cel, it belongs to that cel, etc. There are some special cases: 1. After a Tags chunk, there will be several user data chunks, one for each tag, you should associate the user data in the same order as the tags are in the Tags chunk. 2. After the Tileset chunk, it could be followed by a user data chunk (empty or not) and then all the user data chunks of the tiles ordered by tile index, or it could be followed by none user data chunk (if the file was created in an older Aseprite version of if no tile has user data). 3. In Aseprite v1.3 a sprite has associated user data, to consider this case there is an User Data Chunk at the first frame after the Palette Chunk. The data of this chunk is as follows: DWORD Flags 1 = Has text 2 = Has color 4 = Has properties + If flags have bit 1 STRING Text + If flags have bit 2 BYTE Color Red (0-255) BYTE Color Green (0-255) BYTE Color Blue (0-255) BYTE Color Alpha (0-255) + If flags have bit 4 DWORD Size in bytes of all properties maps stored in this chunk The size includes the this field and the number of property maps (so it will be a value greater or equal to 8 bytes). DWORD Number of properties maps + For each properties map: DWORD Properties maps key == 0 means user properties != 0 means an extension Entry ID (see External Files Chunk)) DWORD Number of properties + For each property: STRING Name WORD Type + If type==0x0001 (bool) BYTE == 0 means FALSE != 0 means TRUE + If type==0x0002 (int8) BYTE + If type==0x0003 (uint8) BYTE + If type==0x0004 (int16) SHORT + If type==0x0005 (uint16) WORD + If type==0x0006 (int32) LONG + If type==0x0007 (uint32) DWORD + If type==0x0008 (int64) LONG64 + If type==0x0009 (uint64) QWORD + If type==0x000A FIXED + If type==0x000B FLOAT + If type==0x000C DOUBLE + If type==0x000D STRING + If type==0x000E POINT + If type==0x000F SIZE + If type==0x0010 RECT + If type==0x0011 (vector) DWORD Number of elements WORD Element's type. + If Element's type == 0 (all elements are not of the same type) For each element: WORD Element's type BYTE[] Element's value. Structure depends on the element's type + Else (all elements are of the same type) For each element: BYTE[] Element's value. Structure depends on the element's type + If type==0x0012 (nested properties map) DWORD Number of properties BYTE[] Nested properties data Structure is the same as indicated in this loop + If type==0x0013 UUID ### Slice Chunk (0x2022) DWORD Number of "slice keys" DWORD Flags 1 = It's a 9-patches slice 2 = Has pivot information DWORD Reserved STRING Name + For each slice key DWORD Frame number (this slice is valid from this frame to the end of the animation) LONG Slice X origin coordinate in the sprite LONG Slice Y origin coordinate in the sprite DWORD Slice width (can be 0 if this slice hidden in the animation from the given frame) DWORD Slice height + If flags have bit 1 LONG Center X position (relative to slice bounds) LONG Center Y position DWORD Center width DWORD Center height + If flags have bit 2 LONG Pivot X position (relative to the slice origin) LONG Pivot Y position (relative to the slice origin) ### Tileset Chunk (0x2023) DWORD Tileset ID DWORD Tileset flags 1 - Include link to external file 2 - Include tiles inside this file 4 - Tilemaps using this tileset use tile ID=0 as empty tile (this is the new format). In rare cases this bit is off, and the empty tile will be equal to 0xffffffff (used in internal versions of Aseprite) 8 - Aseprite will try to match modified tiles with their X flipped version automatically in Auto mode when using this tileset. 16 - Same for Y flips 32 - Same for D(iagonal) flips DWORD Number of tiles WORD Tile Width WORD Tile Height SHORT Base Index: Number to show in the screen from the tile with index 1 and so on (by default this is field is 1, so the data that is displayed is equivalent to the data in memory). But it can be 0 to display zero-based indexing (this field isn't used for the representation of the data in the file, it's just for UI purposes). BYTE[14] Reserved STRING Name of the tileset + If flag 1 is set DWORD ID of the external file. This ID is one entry of the the External Files Chunk. DWORD Tileset ID in the external file + If flag 2 is set DWORD Compressed data length PIXEL[] Compressed Tileset image (see NOTE.3): (Tile Width) x (Tile Height x Number of Tiles) ## Notes ### NOTE.1 The child level is used to show the relationship of this layer with the last one read, for example: Layer name and hierarchy Child Level ----------------------------------------------- - Background 0 `- Layer1 1 - Foreground 0 |- My set1 1 | `- Layer2 2 `- Layer3 1 ### NOTE.2 The layer index is a number to identify a layer in the sprite. Layers are numbered in the same order as Layer Chunks (0x2004) appear in the file, for example: Layer name and hierarchy Layer index ----------------------------------------------- - Background 0 `- Layer1 1 - Foreground 2 |- My set1 3 | `- Layer2 4 `- Layer3 5 It means that in the file you will find the `Background` layer chunk first, then the `Layer1` layer chunk, etc. ### NOTE.3 **Uncompressed Image**: Uncompressed ("raw") images inside `.aseprite` files are saved row by row from top to bottom, and for each row/scanline, pixels are from left to right. Each pixel is a `PIXEL` (or a `TILE` in the case of tilemaps) as defined in the [References](#references) section (so the number and order of bytes depends on the color mode of the image/sprite, or the tile format). Generally you'll not find uncompressed images in `.aseprite` files (only in very old `.aseprite` files). **Compressed Image**: When an image is compressed (the regular case that you will find in `.aseprite` files), the data is a stream of bytes in exactly the same *"Uncompressed Image"* format as described above, but compressed using the ZLIB method. Details about the ZLIB and DEFLATE compression methods can be found here: * https://www.ietf.org/rfc/rfc1950 * https://www.ietf.org/rfc/rfc1951 * Some extra notes that might help you to decode the data: http://george.chiramattel.com/blog/2007/09/deflatestream-block-length-does-not-match.html ### NOTE.4 The extension ID must be a string like `publisher/ExtensionName`, for example, the [Aseprite Attachment System](https://github.com/aseprite/Attachment-System) uses `aseprite/Attachment-System`. This string will be used in a future to automatically link to the extension URL in the [Aseprite Store](https://github.com/aseprite/aseprite/issues/1928). ### NOTE.5 In case that you read and render an `.aseprite` file in your game engine/software, you are going to need to process the z-index field for each cel with a specific algorithm. This is a possible C++ code about how to order layers for a specific frame (the `zIndex` must be set depending on the active frame/cel): ```c++ struct Layer { int layerIndex; // See the "layer index" in NOTE.2 int zIndex; // The z-index value for a specific cel in this layer/frame int order() const { return layerIndex + zIndex; } // Function to order with std::sort() by operator<(), // which establish the render order from back to front. bool operator<(const Layer& b) const { return (order() < b.order()) || (order() == b.order() && (zIndex < b.zIndex)); } }; ``` Basically we first compare `layerIndex + zIndex` of each cel, and then if this value is the same, we compare the specific `zIndex` value to disambiguate some scenarios. An example of this implementation can be found in the [RenderPlan code](https://github.com/aseprite/aseprite/blob/8e91d22b704d6d1e95e1482544318cee9f166c4d/src/doc/render_plan.cpp#L77). ## File Format Changes 1. The first change from the first release of the new .ase format, is the new frame duration field. This is because now each frame can have different duration. How to read both formats (old and new one)? You should set all frames durations to the "speed" field read from the main ASE header. Then, if you found a frame with the frame-duration field > 0, you should update the duration of the frame with that value.