Tatlap

A texture atlas packer library/CLI tool.
I know there are a lot of these out there, but I didn't find one that did everything I wanted it to:

• Trim off transparent borders
• Remove duplicates
• Handle non-4-channel images

I also wanted a project to learn Rust with, and making a command-line tool was a perfect candidate.

Examples

Combine three images into a texture atlas: Console $ tatlap sprite1.png sprite2.png sprite3.png You can specify the output name (defaults to out): Console $ tatlap --out sprites data/*.png If you have a lot of images to pack you can put their names in a file: Console $ tatlap --file list_of_sprites.txt Or pass them through standard input: Console $ echo 'sprite1.png sprite2.png sprite3.png' | tatlap --stdin Actually I'm sure sure why I have the --file option anymore, since you could do this instead: Console $ tatlap < list_of_sprites.txt You can also load images from a texture atlas you created previously: Console $ tatlap --atlas out newsprite.png You can also remove duplicate images from the atlas: Console $ tatlap *.png --dedup

Output

Tatlap will output an out.txt file, an out.bin file, and several outN.png files where N is the number of channels the image contains.

The .txt output file contains locations of the packed sprites.

For example: 4 459 638 45 37 69 53 192 192

• 4 - This represent the number of color channels this image has.
• 459 638 - These are the x and y pixel coordinates where the sprite was packed into the resulting texture atlas
• 45 37 - This is the dimensions of the sprite after the transparent borders were trimmed off
• 67 53 - This is how many pixels from the left and top were trimmed off
• 192 192 - The dimensions of the image before it was trimmed

The .bin output file contains the same data as the .txt output, but contains the values in serialized in a binary file. The first value (bytes per pixel) is a single byte, but the others are 16-bit unsigned integers (in little endian), so each image takes 17 bytes.

How you use the .txt and .bin is up to you; I find the .bin more useful for loading the sprites. Here is an example of how to would load it in C: ``` C FILE* fp = fopen("out.bin"); uint8t bpp; fread(&bpp 1, 1, fp); uint16t d[8]; fread(&xywh, 2, 8, fp); // Note that this won't work on big-endian systems

// Extract the sprite based on d[0-4]

// Calculate where to draw the sprite centered on x and y // x - half uncropped width + cropped offset int drawx = x - d[6]/2 + d[4]; int drawy = y - d[7]/2 + d[5]; ```