fix: optimize kitty rendering (non-cropped)

lua/image/backends/kitty/init.lua

@@ -32,23 +32,27 @@ backend.setup = function(state)
   })
 end
 
--- extend from empty line strategy to use extmarks
+local transmitted_images = {}
 backend.render = function(image, x, y, width, height)
   local with_virtual_placeholders = backend.state.options.kitty_method == "unicode-placeholders"
 
   -- save cursor
   helpers.move_cursor(x + 1, y + 1, true)
 
   -- transmit image
-  helpers.write_graphics({
+  if transmitted_images[image.id] ~= image.crop_hash then
     action = codes.control.action.transmit,
-    image_id = image.internal_id,
-    transmit_format = codes.control.transmit_format.png,
-    transmit_medium = codes.control.transmit_medium.file,
-    display_cursor_policy = codes.control.display_cursor_policy.do_not_move,
-    display_virtual_placeholder = with_virtual_placeholders and 1 or 0,
-    quiet = 2,
-  }, image.path)
+    helpers.write_graphics({
+      action = codes.control.action.transmit,
+      image_id = image.internal_id,
+      transmit_format = codes.control.transmit_format.png,
+      transmit_medium = codes.control.transmit_medium.file,
+      display_cursor_policy = codes.control.display_cursor_policy.do_not_move,
+      display_virtual_placeholder = with_virtual_placeholders and 1 or 0,
+      quiet = 2,
+    }, image.path)
+    transmitted_images[image.id] = true
+  end
 
   -- unicode placeholders
   if with_virtual_placeholders then
@@ -94,7 +98,7 @@ backend.clear = function(image_id, shallow)
     if not image then return end
     helpers.write_graphics({
       action = codes.control.action.delete,
-      display_delete = "i",
+      display_delete = shallow and "i" or "I",
       image_id = image.internal_id,
       quiet = 2,
     })

lua/image/image.lua

@@ -59,7 +59,7 @@ local from_file = function(path, options, state)
     },
     with_virtual_padding = opts.with_virtual_padding or false,
     is_rendered = false,
-    is_cropped = false,
+    crop_hash = nil,
   }
 
   ---@param geometry? ImageGeometry

lua/image/renderer.lua

@@ -147,6 +147,7 @@ local render = function(image, state)
 
   if image.window and image.buffer then
     local win_info = vim.fn.getwininfo(image.window)[1]
+    if not win_info then return false end
     local topline = win_info.topline
     local botline = win_info.botline
 
@@ -281,7 +282,8 @@ local render = function(image, state)
   end
 
   -- perform crop
-  if needs_crop or (image.is_cropped and not needs_crop) then
+  local crop_hash = needs_crop and ("%d-%d-%d-%d"):format(pixel_width, pixel_height, 0, crop_offset_top) or nil
+  if crop_hash or (image.crop_hash ~= crop_hash) then
     local cropped_image = magick.load_image(image.original_path)
     cropped_image:set_format("png")
     utils.debug(("cropping image: %d, %d, %d, %d"):format(pixel_width, pixel_height, 0, crop_offset_top))
@@ -290,7 +292,7 @@ local render = function(image, state)
     cropped_image:write(tmp_path)
     cropped_image:destroy()
     image.path = tmp_path
-    image.is_cropped = true
+    image.crop_hash = crop_hash
   end
 
   -- utils.debug(("(5) x: %d, y: %d, width: %d, height: %d y_offset: %d"):format(x, y, width, height, y_offset))

lua/types.lua

@@ -87,7 +87,7 @@
 ---@field rendered_geometry ImageGeometry
 ---@field bounds ImageBounds
 ---@field is_rendered boolean
----@field is_cropped boolean
+---@field crop_hash? string
 ---@field render fun(geometry?: ImageGeometry)
 ---@field clear fun()
 
@@ -134,4 +134,4 @@
 ---@field display_cursor_policy 0|1
 ---@field display_virtual_placeholder 0|1
 ---@field display_zindex number
----@field display_delete "a"|"i"|"p"
+---@field display_delete "a"|"i"|"I"|"p"