Kitty Graphics Protocol in OCaml
anil.recoil.org
terminal
graphics
ocaml
1(** Pixel Composition Mode
2
3 Controls how pixels are blended when compositing images or animation frames.
4
5 {2 Protocol Details}
6
7 The composition mode is specified via the [X] key in the control data
8 (for animation frames) or the [C] key (for frame composition operations):
9 - Value 0 or omitted: alpha blending (default)
10 - Value 1: simple overwrite/replacement
11
12 {2 Alpha Blending}
13
14 [{`Alpha_blend}] performs standard alpha compositing using the source
15 pixel's alpha channel. For each pixel:
16 - If source alpha is 255 (opaque), source pixel replaces destination
17 - If source alpha is 0 (transparent), destination pixel is unchanged
18 - Otherwise, colors are blended proportionally
19
20 This mode is essential for:
21 - Transparent PNG images
22 - Overlaying graphics on backgrounds
23 - Anti-aliased edges and text
24
25 {2 Overwrite Mode}
26
27 [{`Overwrite}] simply replaces destination pixels with source pixels,
28 ignoring the alpha channel. This is useful for:
29 - Performance optimization when transparency isn't needed
30 - Replacing rectangular regions entirely
31 - Animation frames that completely replace the previous frame *)
32
33type t = [ `Alpha_blend | `Overwrite ]
34(** Composition modes.
35
36 - [`Alpha_blend] - Full alpha blending (default). Source pixels are
37 composited onto the destination using standard Porter-Duff "over"
38 compositing based on the source alpha channel.
39 - [`Overwrite] - Simple pixel replacement. Source pixels completely
40 replace destination pixels, ignoring alpha values. Faster but no
41 transparency support. *)
42
43val to_int : t -> int
44(** Convert to protocol integer.
45
46 Returns 0 for [`Alpha_blend] or 1 for [`Overwrite].
47 These values are used in the [X=] or [C=] control data keys. *)