Cleaned up some code.

src/modules/image/wrap_ImageData.lua

@@ -23,8 +23,9 @@ misrepresented as being the original software.
 --]]
 
 local ImageData_mt, ffifuncspointer = ...
+local ImageData = ImageData_mt.__index
 
-local tonumber, assert = tonumber, assert
+local tonumber, assert, error = tonumber, assert, error
 local type, pcall = type, pcall
 
 local function inside(x, y, w, h)
@@ -33,7 +34,7 @@ end
 
 -- Implement thread-safe ImageData:mapPixel regardless of whether the FFI is
 -- used or not.
-function ImageData_mt.__index:mapPixel(func, ix, iy, iw, ih)
+function ImageData:mapPixel(func, ix, iy, iw, ih)
 	local idw, idh = self:getDimensions()
 
 	ix = ix or 0
@@ -41,13 +42,13 @@ function ImageData_mt.__index:mapPixel(func, ix, iy, iw, ih)
 	iw = iw or idw
 	ih = ih or idh
 
-	assert(type(ix) == "number", "Invalid argument #2 to ImageData:mapPixel (expected number)")
-	assert(type(iy) == "number", "Invalid argument #3 to ImageData:mapPixel (expected number)")
-	assert(type(iw) == "number", "Invalid argument #4 to ImageData:mapPixel (expected number)")
-	assert(type(ih) == "number", "Invalid argument #5 to ImageData:mapPixel (expected number)")
+	if type(ix) ~= "number" then error("Invalid argument #2 to ImageData:mapPixel (expected number)", 2) end
+	if type(iy) ~= "number" then error("Invalid argument #3 to ImageData:mapPixel (expected number)", 2) end
+	if type(iw) ~= "number" then error("Invalid argument #4 to ImageData:mapPixel (expected number)", 2) end
+	if type(ih) ~= "number" then error("Invalid argument #5 to ImageData:mapPixel (expected number)", 2) end
 
-	assert(type(func) == "function", "Invalid argument #1 to ImageData:mapPixel (expected function)")
-	assert(inside(ix, iy, idw, idh) and inside(ix+iw-1, iy+ih-1, idw, idh), "Invalid rectangle dimensions")
+	if type(func) ~= "function" then error("Invalid argument #1 to ImageData:mapPixel (expected function)", 2) end
+	if not (inside(ix, iy, idw, idh) and inside(ix+iw-1, iy+ih-1, idw, idh)) then error("Invalid rectangle dimensions", 2) end
 
 	-- performAtomic and mapPixelUnsafe have Lua-C API and FFI versions.
 	self:_performAtomic(self._mapPixelUnsafe, self, func, ix, iy, iw, ih)
@@ -85,9 +86,9 @@ local ffifuncs = ffi.cast("FFI_ImageData *", ffifuncspointer)
 
 local pixelpointer = ffi.typeof("ImageData_Pixel *")
 
-local _getWidth = ImageData_mt.__index.getWidth
-local _getHeight = ImageData_mt.__index.getHeight
-local _getDimensions = ImageData_mt.__index.getDimensions
+local _getWidth = ImageData.getWidth
+local _getHeight = ImageData.getHeight
+local _getDimensions = ImageData.getDimensions
 
 -- Table which holds ImageData objects as keys, and information about the objects
 -- as values. Uses weak keys so the ImageData objects can still be GC'd properly.
@@ -111,7 +112,7 @@ local objectcache = setmetatable({}, {
 
 -- Overwrite existing functions with new FFI versions.
 
-function ImageData_mt.__index:_performAtomic(...)
+function ImageData:_performAtomic(...)
 	ffifuncs.lockMutex(self)
 	local success, err = pcall(...)
 	ffifuncs.unlockMutex(self)
@@ -121,7 +122,7 @@ function ImageData_mt.__index:_performAtomic(...)
 	end
 end
 
-function ImageData_mt.__index:_mapPixelUnsafe(func, ix, iy, iw, ih)
+function ImageData:_mapPixelUnsafe(func, ix, iy, iw, ih)
 	local p = objectcache[self]
 	local idw, idh = p.width, p.height
 
@@ -139,9 +140,9 @@ function ImageData_mt.__index:_mapPixelUnsafe(func, ix, iy, iw, ih)
 	end
 end
 
-function ImageData_mt.__index:getPixel(x, y)
+function ImageData:getPixel(x, y)
 	local p = objectcache[self]
-	assert(inside(x, y, p.width, p.height), "Attempt to get out-of-range pixel!")
+	if not inside(x, y, p.width, p.height) then error("Attempt to get out-of-range pixel!", 2) end
 
 	ffifuncs.lockMutex(self)
 	local pixel = p.pointer[y * p.width + x]
@@ -153,9 +154,9 @@ end
 
 local temppixel = ffi.new("ImageData_Pixel")
 
-function ImageData_mt.__index:setPixel(x, y, r, g, b, a)	
+function ImageData:setPixel(x, y, r, g, b, a)	
 	local p = objectcache[self]
-	assert(inside(x, y, p.width, p.height), "Attempt to set out-of-range pixel!")
+	if not inside(x, y, p.width, p.height) then error("Attempt to set out-of-range pixel!", 2) end
 
 	if type(r) == "table" then
 		local t = r
@@ -172,15 +173,15 @@ function ImageData_mt.__index:setPixel(x, y, r, g, b, a)
 	ffifuncs.unlockMutex(self)
 end
 
-function ImageData_mt.__index:getWidth()
+function ImageData:getWidth()
 	return objectcache[self].width
 end
 
-function ImageData_mt.__index:getHeight()
+function ImageData:getHeight()
 	return objectcache[self].height
 end
 
-function ImageData_mt.__index:getDimensions()
+function ImageData:getDimensions()
 	local p = objectcache[self]
 	return p.width, p.height
 end