Initial commit

.config/lite-xl/plugins/lintplus/renderutil.lua

@@ -0,0 +1,44 @@
+-- rendering utilities
+
+local common = require "core.common"
+
+local renderutil = {}
+
+function renderutil.draw_dotted_line(x, y, length, axis, color)
+  if axis == 'x' then
+    for xx = x, x + length, 2 do
+      renderer.draw_rect(xx, y, 1, 1, color)
+    end
+  elseif axis == 'y' then
+    for yy = y, y + length, 2 do
+      renderer.draw_rect(x, yy, 1, 1, color)
+    end
+  end
+end
+
+local function plot(x, y, color)
+  renderer.draw_rect(x, y, 1, 1, color)
+end
+
+function renderutil.draw_quarter_circle(x, y, r, color, flipy)
+  -- inefficient for large circles, but it works.
+  color = { table.unpack(color) }
+  local a = color[4]
+  for dx = 0, r - 1 do
+    for dy = 0, r - 1 do
+      local xx = r - 1 - dx
+      local yy = dy
+      if not flipy then
+        yy = r - 1 - dy
+      end
+      local t = math.abs(math.sqrt(xx*xx + yy*yy) - r + 1)
+      t = common.clamp(1 - t, 0, 1)
+      if t > 0 then
+        color[4] = a * t
+        plot(x + dx, y + dy, color)
+      end
+    end
+  end
+end
+
+return renderutil