add font preview plugin (#392)

* add font preview plugin

* remove get_scrollable_size and unused variable

* add a list of supported font types

I also realized I haven't been returning the view that `open_doc`
returns, so I fixed that too

* add rows for every printable character in ASCII

* deactivate vertical scrolling

* properly mark patterns in supported_types list

Co-authored-by: Guldoman <giulio.lettieri@gmail.com>

---------

Co-authored-by: Guldoman <giulio.lettieri@gmail.com>

2 files changed, 82 insertions, 0 deletions

diff --git a/manifest.json b/manifest.json
index 64819a3..fa0a2d2 100644
--- a/manifest.json
+++ b/manifest.json
@@ -301,6 +301,13 @@
       "version": "0.1"
     },
     {
+      "description": "Automatically displays a font with increasing sizes in a new view.",
+      "version": "0.1",
+      "path": "plugins/fontpreview.lua",
+      "id": "fontpreview",
+      "mod_version": "3"
+    },
+    {
       "description": "Debug Lite-XL's Lua VM interactively, if you're running it from a terminal. Warning: Will significantly slow down Lite-XL if installed.",
       "id": "lite-debugger",
       "mod_version": "3",
diff --git a/plugins/fontpreview.lua b/plugins/fontpreview.lua
new file mode 100644
index 0000000..0ce8fc0
--- /dev/null
+++ b/plugins/fontpreview.lua
@@ -0,0 +1,75 @@
+--mod-version:3 --priority:110
+
+local common = require 'core.common'
+local style = require 'core.style'
+local View = require 'core.view'
+
+local FontView = View:extend()
+
+local font_text = "The quick brown fox jumps over the lazy dog."
+
+function FontView:new(path)
+	FontView.super.new(self)
+	self.path = path
+	self.fonts = {}
+	for i=1, 8 do self.fonts[i] = renderer.font.load(path, (12+i*7)*SCALE) end
+	self.scrollable = true
+end
+
+function FontView:get_h_scrollable_size()
+	return self.fonts[#self.fonts]:get_width(font_text) + style.padding.x
+end
+
+function FontView:get_scrollable_size() return 0 end
+
+function FontView:get_name()
+	return "Font: " .. self.path
+end
+
+local function draw_next_row(fv, y, text, font)
+	local _
+	_, y = common.draw_text(
+		font, style.text, text, "left",
+		fv.position.x - fv.scroll.x + style.padding.x, y - fv.scroll.y,
+		0, style.padding.y + font:get_height() / 2
+	)
+	return y
+end
+
+function FontView:draw()
+	self:draw_background(style.background)
+
+	local y = self.position.y + self.fonts[1]:get_height() / 2 + style.padding.y
+
+	for i=1, #self.fonts do
+		y = draw_next_row(self, y, font_text, self.fonts[i])
+	end
+
+	local font = self.fonts[1]
+	y = draw_next_row(self, y, "abcdefghijklmnopqrstuvwxyz", font)
+	y = draw_next_row(self, y, "ABCDEFGHIJKLMNOPQRSTUVWXYZ", font)
+	y = draw_next_row(self, y, "0123456789", font)
+	y = draw_next_row(self, y, "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~", font)
+
+	self:draw_scrollbar()
+end
+
+local supported_types = { "%.ttf$", "%.otf$" }
+
+local RootView = require 'core.rootview'
+local open_doc = RootView.open_doc
+function RootView:open_doc(doc)
+	local path = doc.filename or doc.abs_filename or ""
+
+	for _, v in ipairs(supported_types) do
+		if path:find(v) then
+			local node = self:get_active_node_default()
+			local view = FontView(path)
+			node:add_view(view)
+			self.root_node:update_layout()
+			return view
+		end
+	end
+
+	return open_doc(self, doc)
+end