Added `scale` plugin

2 files changed, 63 insertions, 0 deletions

diff --git a/README.md b/README.md
index 9c8a18d..466160a 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,7 @@ Plugin | Description
 [`motiontrail`](plugins/motiontrail.lua?raw=1) | Adds a motion-trail to the caret *([screenshot](https://user-images.githubusercontent.com/3920290/83256814-085ccb00-a1ab-11ea-9e35-e6633cbed1a9.gif))*
 [`openfilelocation`](plugins/openfilelocation.lua?raw=1) | Opens the parent directory of the current file in the file manager
 [`openselected`](plugins/openselected.lua?raw=1) | Opens the selected filename or url
+[`scale`](plugins/scale.lua?raw=1) | Provides support for dynamically adjusting the scale of the UI (`ctrl+-`, `ctrl+=`)
 [`selectionhighlight`](plugins/selectionhighlight.lua?raw=1) | Highlights regions of code that match the current selection *([screenshot](https://user-images.githubusercontent.com/3920290/80710883-5f597c80-8ae7-11ea-97f0-76dfacc08439.png))*
 [`sort`](plugins/sort.lua?raw=1) | Sorts selected lines alphabetically
 [`spellcheck`](plugins/spellcheck.lua?raw=1) | Underlines misspelt words *([screenshot](https://user-images.githubusercontent.com/3920290/79923973-9caa7400-842e-11ea-85d4-7a196a91ca50.png))* On Windows no dictionary file exists for spellchecking. You can add a words.txt file beside the exe to remedy this. [Example file](https://github.com/dwyl/english-words/blob/master/words.txt)
diff --git a/plugins/scale.lua b/plugins/scale.lua
new file mode 100644
index 0000000..52ac73b
--- /dev/null
+++ b/plugins/scale.lua
@@ -0,0 +1,62 @@
+local core = require "core"
+local command = require "core.command"
+local keymap = require "core.keymap"
+local style = require "core.style"
+
+
+local font_cache = setmetatable({}, { __mode = "k" })
+
+-- the following should be kept in sync with core.style's default font settings
+font_cache[style.font]      = { EXEDIR .. "/data/fonts/font.ttf",      14   * SCALE }
+font_cache[style.big_font]  = { EXEDIR .. "/data/fonts/font.ttf",      34   * SCALE }
+font_cache[style.icon_font] = { EXEDIR .. "/data/fonts/icons.ttf",     14   * SCALE }
+font_cache[style.code_font] = { EXEDIR .. "/data/fonts/monospace.ttf", 13.5 * SCALE }
+
+
+local load_font = renderer.font.load
+function renderer.font.load(...)
+  local res = load_font(...)
+  font_cache[res] = { ... }
+  return res
+end
+
+
+local function scale_font(font, s)
+  local fc = font_cache[font]
+  return renderer.font.load(fc[1], fc[2] * s)
+end
+
+
+local function set_scale(scale)
+  local s = scale / SCALE
+
+  style.padding.x      = style.padding.x      * s
+  style.padding.y      = style.padding.y      * s
+  style.divider_size   = style.divider_size   * s
+  style.scrollbar_size = style.scrollbar_size * s
+  style.caret_width    = style.caret_width    * s
+  style.tab_width      = style.tab_width      * s
+
+  style.font      = scale_font(style.font,      s)
+  style.big_font  = scale_font(style.big_font,  s)
+  style.icon_font = scale_font(style.icon_font, s)
+  style.code_font = scale_font(style.code_font, s)
+
+  SCALE = scale
+  core.redraw = true
+end
+
+
+command.add(nil, {
+  ["scale:reset"   ] = function() set_scale(1)           end,
+  ["scale:decrease"] = function() set_scale(SCALE * 0.9) end,
+  ["scale:increase"] = function() set_scale(SCALE * 1.1) end,
+})
+
+keymap.add {
+  ["ctrl+0"] = "scale:reset",
+  ["ctrl+-"] = "scale:decrease",
+  ["ctrl+="] = "scale:increase",
+}
+
+return { set_scale = set_scale }