add animation

1 files changed, 50 insertions, 0 deletions

diff --git a/lua/alpha/animations.lua b/lua/alpha/animations.lua
new file mode 100644
index 0000000..c0b7a6c
--- /dev/null
+++ b/lua/alpha/animations.lua
@@ -0,0 +1,50 @@
+local redraw_buffer = function()
+  local Animation = require "animation"
+  local fps = 45 -- frames per second
+  local easing = require "animation.easing"
+
+  local buffer = 0
+  local len = 0
+  local place_holder = {}
+
+  local lines = vim.api.nvim_buf_get_lines(buffer, 0, -1, true)
+
+  for _, line in ipairs(lines) do
+    len = len + string.len(line)
+    table.insert(place_holder, "")
+  end
+
+  vim.api.nvim_buf_set_lines(buffer, 0, #lines, true, place_holder)
+
+  local duration = math.ceil(len / fps * 1000)
+
+  local i = 1
+  local line_nr = 1
+  local insertLine = ""
+
+  local function callback()
+    if lines[line_nr] == nil then
+      return true
+    end
+    local char = string.sub(lines[line_nr], i, i)
+    if char == nil then
+      return true
+    end
+    insertLine = insertLine .. char
+    i = i + 1
+    vim.api.nvim_buf_set_lines(buffer, line_nr - 1, line_nr, true, { insertLine })
+
+    if insertLine == lines[line_nr] then
+      i = 1
+      line_nr = line_nr + 1
+      insertLine = ""
+    end
+  end
+
+  local animation = Animation(duration, fps, easing.line, callback)
+  animation:run()
+end
+
+return {
+  redraw_buffer = redraw_buffer,
+}