Rework graphical train HUD code

- A basic texture manipulation API is added; currently this is only a
  (selected) subset of texture modifiers provided by MT; the goal is to
  avoid writing (potentially incorrect) texture strings by hand;
- The graphical HUD code is cleaned up; in particular, most code used
  for generating texture patterns are moved to texture.lua so that the
  code can be used outside of the HUD;
- Inactive elements are given the darkslategray background.

A basic unittest is added; however, it needs to be expanded for better
coverage.

Reported-by: Lars Müller <appgurulars@gmx.de>

1 files changed, 19 insertions, 0 deletions

diff --git a/advtrains/spec/texture_spec.lua b/advtrains/spec/texture_spec.lua
new file mode 100644
index 0000000..2e3bd5d
--- /dev/null
+++ b/advtrains/spec/texture_spec.lua
@@ -0,0 +1,19 @@
+package.path = "../?.lua;" .. package.path
+local T = require "texture"
+
+describe("Texture creation", function()
+	it("works", function()
+		assert.same("^.png", tostring(T.raw"^.png"))
+		assert.same("foo\\:bar.png", tostring(T"foo:bar.png"))
+	end)
+end)
+
+describe("Texture modifiers", function()
+	it("work", function()
+		assert.same("x^[colorize:c", tostring(T"x":colorize"c"))
+		assert.same("x^[colorize:c:alpha", tostring(T"x":colorize("c", "alpha")))
+		assert.same("x^[multiply:c", tostring(T"x":multiply"c"))
+		assert.same("x^[resize:2x3", tostring(T"x":resize(2, 3)))
+		assert.same("x^[transformI", tostring(T"x":transform"I"))
+	end)
+end)