Merge pull request #94 from barrettruth/feat/highlight-config-overrides

Highlight config overrides, default flag, blend alpha

README.md

@@ -18,7 +18,8 @@ syntax highlighting.
 - Vim syntax fallback for languages without a treesitter parser
 - Hunk header context highlighting (`@@ ... @@ function foo()`)
 - Character-level (intra-line) diff highlighting for changed characters
-- Configurable debouncing, max lines, and diff prefix concealment
+- Configurable debouncing, max lines, diff prefix concealment, blend alpha, and
+  highlight overrides
 
 ## Requirements
 

doc/diffs.nvim.txt

@@ -56,6 +56,7 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
       highlights = {
         background = true,
         gutter = true,
+        blend_alpha = 0.6,
         context = {
           enabled = true,
           lines = 25,
@@ -66,13 +67,14 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
         },
         vim = {
           enabled = false,
-          max_lines = 500,
+          max_lines = 200,
         },
         intra = {
           enabled = true,
           algorithm = 'default',
           max_lines = 500,
         },
+        overrides = {},
       },
       fugitive = {
         horizontal = 'du',
@@ -117,6 +119,13 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
                              Highlight line numbers with matching colors.
                              Only visible if line numbers are enabled.
 
+        {blend_alpha}        (number, default: 0.6)
+                             Alpha value for character-level blend intensity.
+                             Controls how strongly changed characters stand
+                             out from the line-level background. Must be
+                             between 0 and 1 (inclusive). Higher values
+                             produce more vivid character-level highlights.
+
         {context}            (table, default: see below)
                              Syntax parsing context options.
                              See |diffs.ContextConfig| for fields.
@@ -133,6 +142,13 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
                              Character-level (intra-line) diff highlighting.
                              See |diffs.IntraConfig| for fields.
 
+        {overrides}          (table, default: {})
+                             Map of highlight group names to highlight
+                             definitions (see |nvim_set_hl()|). Applied
+                             after all computed groups without `default`,
+                             so overrides always win over both computed
+                             defaults and colorscheme definitions.
+
                                                       *diffs.ContextConfig*
     Context config fields: ~
         {enabled}            (boolean, default: true)
@@ -398,9 +414,9 @@ diff-related features.
 ==============================================================================
 HIGHLIGHT GROUPS                                          *diffs-highlights*
 
-diffs.nvim defines custom highlight groups. Fugitive unified diff groups use
+diffs.nvim defines custom highlight groups. All groups use `default = true`,
-`default = true`, so colorschemes can override them. Diff mode groups are
+so colorschemes can override them by defining the group before the plugin
-always derived from the corresponding `Diff*` groups.
+loads.
 
 All derived groups are computed by alpha-blending a source color into the
 `Normal` background. Line-level groups blend at 40% alpha for a subtle tint;
@@ -461,6 +477,16 @@ To customize these in your colorscheme: >lua
     vim.api.nvim_set_hl(0, 'DiffsAdd', { bg = '#2e4a3a' })
     vim.api.nvim_set_hl(0, 'DiffsDiffDelete', { link = 'DiffDelete' })
 <
+Or via `highlights.overrides` in config: >lua
+    vim.g.diffs = {
+      highlights = {
+        overrides = {
+          DiffsAdd = { bg = '#2e4a3a' },
+          DiffsDiffDelete = { link = 'DiffDelete' },
+        },
+      },
+    }
+<
 
 ==============================================================================
 HEALTH CHECK                                                 *diffs-health*

lua/diffs/init.lua

@@ -18,6 +18,8 @@
 ---@class diffs.Highlights
 ---@field background boolean
 ---@field gutter boolean
+---@field blend_alpha? number
+---@field overrides? table<string, table>
 ---@field context diffs.ContextConfig
 ---@field treesitter diffs.TreesitterConfig
 ---@field vim diffs.VimConfig
@@ -192,8 +194,9 @@ local function compute_highlight_groups()
   local blended_add = blend_color(add_bg, bg, 0.4)
   local blended_del = blend_color(del_bg, bg, 0.4)
 
-  local blended_add_text = blend_color(add_fg, bg, 0.6)
+  local alpha = config.highlights.blend_alpha or 0.6
-  local blended_del_text = blend_color(del_fg, bg, 0.6)
+  local blended_add_text = blend_color(add_fg, bg, alpha)
+  local blended_del_text = blend_color(del_fg, bg, alpha)
 
   vim.api.nvim_set_hl(0, 'DiffsClear', { default = true, fg = normal.fg or 0xc0c0c0 })
   vim.api.nvim_set_hl(0, 'DiffsAdd', { default = true, bg = blended_add })
@@ -219,10 +222,20 @@ local function compute_highlight_groups()
   local diff_change = resolve_hl('DiffChange')
   local diff_text = resolve_hl('DiffText')
 
-  vim.api.nvim_set_hl(0, 'DiffsDiffAdd', { bg = diff_add.bg })
+  vim.api.nvim_set_hl(0, 'DiffsDiffAdd', { default = true, bg = diff_add.bg })
-  vim.api.nvim_set_hl(0, 'DiffsDiffDelete', { fg = diff_delete.fg, bg = diff_delete.bg })
+  vim.api.nvim_set_hl(
-  vim.api.nvim_set_hl(0, 'DiffsDiffChange', { bg = diff_change.bg })
+    0,
-  vim.api.nvim_set_hl(0, 'DiffsDiffText', { bg = diff_text.bg })
+    'DiffsDiffDelete',
+    { default = true, fg = diff_delete.fg, bg = diff_delete.bg }
+  )
+  vim.api.nvim_set_hl(0, 'DiffsDiffChange', { default = true, bg = diff_change.bg })
+  vim.api.nvim_set_hl(0, 'DiffsDiffText', { default = true, bg = diff_text.bg })
+
+  if config.highlights.overrides then
+    for group, hl in pairs(config.highlights.overrides) do
+      vim.api.nvim_set_hl(0, group, hl)
+    end
+  end
 end
 
 local function init()
@@ -244,6 +257,8 @@ local function init()
     vim.validate({
       ['highlights.background'] = { opts.highlights.background, 'boolean', true },
       ['highlights.gutter'] = { opts.highlights.gutter, 'boolean', true },
+      ['highlights.blend_alpha'] = { opts.highlights.blend_alpha, 'number', true },
+      ['highlights.overrides'] = { opts.highlights.overrides, 'table', true },
       ['highlights.context'] = { opts.highlights.context, 'table', true },
       ['highlights.treesitter'] = { opts.highlights.treesitter, 'table', true },
       ['highlights.vim'] = { opts.highlights.vim, 'table', true },
@@ -344,6 +359,13 @@ local function init()
   then
     error('diffs: highlights.intra.max_lines must be >= 1')
   end
+  if
+    opts.highlights
+    and opts.highlights.blend_alpha
+    and (opts.highlights.blend_alpha < 0 or opts.highlights.blend_alpha > 1)
+  then
+    error('diffs: highlights.blend_alpha must be >= 0 and <= 1')
+  end
 
   config = vim.tbl_deep_extend('force', default_config, opts)
   log.set_enabled(config.debug)