不同类型的BufferedImage是什么意思？

Question

The documentation of BufferedImage is pretty ... terse.

What do the different types mean? What do I get back when I call getPixel() for TYPE_INT_ARGB ? How is it different from what I get back when the type is TYPE_3BYTE_BGR ? What about the other types?

Answer 1

TYPE_INT_ARGB uses Integer to save a color of pixel, like

int color = 0xAARRGGBB,

but 3BYTE_BGR uses

byte[] color = new byte[Blue, Green, Red]

I recommend uses INT_ARGB, you can use alpha, in 3BYTE there are not channel alpha. Integer is faster, than array of byte and easy, for example to get any color use:

(COLOR >> 16) & 0xFF; (24-16 bits are RED).
(COLOR >>  8) & 0xFF; (16- 8 bits are GREEN).
(COLOR >>  0) & 0xFF; ( 8- 0 bits are BLUE).

I always use INT_ARGB or INT_RGB (if I don't need alpha)

Answer 2

Type represents pixel color type.

Like TYPE_INT_ARGB uses 8 bits for ALPHA component, 8 bits for RED component, 8 bits for GREEN component and 8 bits for BLUE component of color. So pixel color can be stored in int value.

TYPE_3BYTE_BGR do not store ALPHA component of color. It uses only 3 bytes of int value.

Like TYPE_USHORT_555_RGB uses 5 bits for each RED, GREEN and BLUE component of color. As it uses 5 bits only, it will have limited number of colors than TYPE_INT_ARGB or TYPE_3BYTE_BGR.

ALPHA component represents how image is transparent.

Likewise other types defines different color schemes.