Merge fa6c19a5c7 into bc0630e43b

lua/snacks/image/image.lua

@@ -10,7 +10,6 @@
 local M = {}
 M.__index = M
 
-local NVIM_ID_BITS = 10
 local CHUNK_SIZE = 4096
 local MAX_FSIZE = 200 * 1024 * 1024 -- 200MB
 local _id = 30
@@ -57,13 +56,40 @@ function M.new(src)
   images[self.file] = self
   _id = _id + 1
   local bit = require("bit")
+
+  local max_id_bits, nvim_id_bits
+  if Snacks.image.config.cterm256 then
+    max_id_bits = 16
+    nvim_id_bits = 4
+  else
+    max_id_bits = 32
+    nvim_id_bits = 10
+  end
+
   -- generate a unique id for this nvim instance (10 bits)
   if nvim_id == 0 then
     local pid = vim.fn.getpid()
-    nvim_id = bit.band(bit.bxor(pid, bit.rshift(pid, 5), bit.rshift(pid, NVIM_ID_BITS)), 0x3FF)
+    local mask = bit.lshift(1, nvim_id_bits) - 1
+    nvim_id = bit.band(bit.bxor(pid, bit.rshift(pid, 5), bit.rshift(pid, nvim_id_bits)), mask)
   end
+
   -- interleave the nvim id and the image id
-  self.id = bit.bor(bit.lshift(nvim_id, 24 - NVIM_ID_BITS), _id)
+  if Snacks.image.config.cterm256 then
+    local lower = bit.band(_id, 0xff)
+    local upper = bit.band(bit.rshift(_id, 8), 0xff)
+    upper = bit.bor(bit.lshift(nvim_id, 8 - nvim_id_bits), upper)
+    -- upper will be send via a diacritic (bits 24-31), lower is a cterm fg (256 colors)
+    self.id = bit.bor(bit.lshift(upper, 24), lower)
+  else
+    self.id = bit.bor(bit.lshift(nvim_id, max_id_bits - nvim_id_bits), _id)
+  end
+
+  -- TODO: better way to deal with bitwise signed: if bitwise ops set the most significant bit,
+  --       then the number is treated as negative, but regular math ops do not
+  if self.id < 0 then
+    self.id = bit.rshift(self.id, 1) * 2
+  end
+
   self.placements = {}
 
   self:run()

lua/snacks/image/init.lua

@@ -39,6 +39,7 @@ M.meta = {
 
 ---@class snacks.image.Config
 ---@field enabled? boolean enable image viewer
+---@field cterm256? boolean use 256 colors for image ids
 ---@field wo? vim.wo|{} options for windows showing the image
 ---@field bo? vim.bo|{} options for the image buffer
 ---@field formats? string[]

lua/snacks/image/placement.lua

@@ -203,12 +203,16 @@ end
 --- Renders the unicode placeholder grid in the buffer
 ---@param loc snacks.image.Loc
 function M:render_grid(loc)
+  local bit = require("bit")
+  local upper_id = bit.band(bit.rshift(self.img.id, 24), 0xff)
+
   local hl = "SnacksImage" .. self.id -- image id is encoded in the foreground color
   Snacks.util.set_hl({
     [hl] = {
-      fg = self.img.id,
+      fg = bit.band(self.img.id, 0xffffff),
       sp = self.id,
       bg = Snacks.image.config.debug.placement and "#FF007C" or "none",
+      ctermfg = bit.band(self.img.id, 0xff),
       nocombine = true,
     },
   })
@@ -222,6 +226,9 @@ function M:render_grid(loc)
       line[#line + 1] = PLACEHOLDER
       line[#line + 1] = positions[r]
       line[#line + 1] = positions[c]
+      if upper_id > 0 then
+        line[#line + 1] = positions[upper_id + 1]
+      end
     end
     img[#img + 1] = table.concat(line)
   end