Vendor selectionhighlight, bracketmatch, colorpreview, navigate, editorconfig (2.1.8-7)

Five more plugins from lite-xl-plugins @ 31eef29, all default VSCode
behaviors:

- selectionhighlight: highlights other occurrences of the selected word
- bracketmatch: highlights the bracket matching the one under the cursor
- colorpreview: inline swatches for #hex/rgb()/hsl() color literals
- navigate: Go Back / Go Forward cursor history (alt+left/right)
- editorconfig: applies .editorconfig files; vendored as the whole
  upstream directory (parser + test harness, lite-xl test editorconfig);
  builds on the bundled trimwhitespace plugin

All depend on core only (editorconfig additionally on trimwhitespace,
already shipped). Verified against the built package: all plugins load,
navigate registers its commands, and an .editorconfig with
indent_size = 2 is applied to an opened file.

Pinned to lite-xl-plugins @ 31eef29 (see debian/extra/README.source).

debian/extra/plugins/colorpreview.lua

@@ -0,0 +1,88 @@
+-- mod-version:3
+local config = require "core.config"
+local common = require "core.common"
+local DocView = require "core.docview"
+
+
+config.plugins.colorpreview = common.merge({
+  enabled = true,
+  -- The config specification used by the settings gui
+  config_spec = {
+    name = "Color Preview",
+    {
+      label = "Enable",
+      description = "Enable or disable the color preview feature.",
+      path = "enabled",
+      type = "toggle",
+      default = true
+    }
+  }
+}, config.plugins.colorpreview)
+
+local white = { common.color "#ffffff" }
+local black = { common.color "#000000" }
+local tmp = {}
+
+
+local function draw_color_previews(self, line, x, y, ptn, base, nibbles)
+  local text = self.doc.lines[line]
+  local s, e = 0, 0
+
+  while true do
+    s, e = text:find(ptn, e + 1)
+    if not s then break end
+
+    local str = text:sub(s, e)
+    local r, g, b, a = str:match(ptn)
+    r, g, b = tonumber(r, base), tonumber(g, base), tonumber(b, base)
+    a = tonumber(a or "", base)
+    if a ~= nil then
+      if base ~= 16 then
+        a = a * 0xff
+      end
+    else
+      a = 0xff
+    end
+
+    -- #123 becomes #112233
+    if nibbles then
+      r = r * 16
+      g = g * 16
+      b = b * 16
+    end
+
+    local x1 = x + self:get_col_x_offset(line, s)
+    local x2 = x + self:get_col_x_offset(line, e + 1)
+    local oy = self:get_line_text_y_offset()
+
+    local text_color = math.max(r, g, b) < 128 and white or black
+    tmp[1], tmp[2], tmp[3], tmp[4] = r, g, b, a
+
+    local l1, _, l2, _ = self.doc:get_selection(true)
+
+    if not (self.doc:has_selection() and line >= l1 and line <= l2) then
+      renderer.draw_rect(x1, y, x2 - x1, self:get_line_height(), tmp)
+      renderer.draw_text(self:get_font(), str, x1, y + oy, text_color)
+    end
+  end
+end
+
+
+local draw_line_text = DocView.draw_line_text
+
+function DocView:draw_line_text(line, x, y)
+  local lh = draw_line_text(self, line, x, y)
+  if config.plugins.colorpreview.enabled then
+    draw_color_previews(self, line, x, y,
+      "#(%x%x)(%x%x)(%x%x)(%x?%x?)%f[%W]",
+      16
+    )
+    -- support #fff css format
+    draw_color_previews(self, line, x, y, "#(%x)(%x)(%x)%f[%W]", 16, true)
+    draw_color_previews(self, line, x, y,
+      "rgba?%((%d+)%D+(%d+)%D+(%d+)[%s,]-([%.%d]-)%s-%)",
+      nil
+    )
+  end
+  return lh
+end