[python]python打包小图片到大图（类型于TexturePacker的功能）

参数说明：

Packer Setting
bg_color
The background color of output image. The pixels of the empty area in the output image will be filled with bg_color. The default value is 0x00000000, which is in format of “RGBA”. A tuple of values can also be accepted, like (R, G, B, A).

texture_format
Choose the texture format that the output file will use, for example “.jpg”. The default texture format is “.png”.

max_width
Sets the maximum width for the texture, default is 4096.

max_height
Sets the maximum height for the texture, default is 4096.

enable_rotated
Allows the rotating of sprites clockwise or counterclockwise by 90 degrees if they have a better fit in the texture. Might not be supported by all game/web frameworks.

force_square
Forces the texture to have a squared size.

border_padding
Border padding is the space between the sprites and the border of the sprite sheet. Value adds transparent pixels around the borders of the sprite sheet. Default is 2.

shape_padding
Shape padding is the space between sprites. Value adds transparent pixels between sprites to avoid artifacts from neighbor sprites. The transparent pixels are not added to the sprites. Default is 2. Use a value of at least 2 to avoid dragging in pixels from neighbor sprites when using OpenGL rendering.

inner_padding
Adds transparent pixels to the inside of the sprite, growing it. Default is 0.

There are two uses for this:

It can help in preventing cut-off artifacts near the edges of scaled sprites. E.g. if your sprite has a few pixels along its own boundaries, scaling the sprite up or down won’t let these pixels appear as gaps or cuts.
It considerably reduces aliasing along the polygon edges when rotating trimmed or cropped sprites. E.g. if your sprite has many pixels along its own boundaries, it will be drawn more smoothly when rotating it.
trim_mode
Removes transparent pixels from a sprite’s border. This shrinks the sprite’s size, allows tighter packing of the sheet, and speeds up rendering since transparent pixels don’t need to be processed. Pixels with an alpha value below this value will be considered transparent when trimming the sprite. Allowed values: 0 to 255, default is 0. When it’s set to 0, the trim mode is disabled. Very useful for sprites with nearly invisible alpha pixels at the borders.

reduce_border_artifacts
Adds color to transparent pixels by repeating a sprite’s outer color values. These color values can reduce artifacts around sprites and removes dark halos at transparent borders. This feature is also known as “Alpha bleeding”.

extrude
Extrude repeats the sprite’s pixels at the border. Sprite’s size is not changed.

There are two uses for this:

Reduce flickering in some cases where sprites have to be put next to each other in the final program.
Check if sprite outlines are OK. E.g. if you want to use sprites to create tilemaps this allows you to see if there are semi-transparent pixels at the borders of the tiles.
atlas_format
Choose the texture config format that file will use. Available options “plist” or “json”. The default texture config output format is “plist”.