initial commit

src/import/ImageWriter.lua

@@ -0,0 +1,143 @@
+local ImageWriter = {}
+
+local SHADES = {
+  { 1, 1, 1, 1 },
+  { 2 / 3, 2 / 3, 2 / 3, 1 },
+  { 1 / 3, 1 / 3, 1 / 3, 1 },
+  { 0, 0, 0, 1 },
+}
+
+local function assertDimensions(raw, width, height, bits)
+  assert(width % 8 == 0 and height % 8 == 0,
+    ("%dbpp dimensions must be tile-aligned: %dx%d")
+      :format(bits, width, height))
+  local expected = width * height * bits / 8
+  assert(#raw == expected,
+    ("%dbpp payload is %d bytes, expected %d")
+      :format(bits, #raw, expected))
+end
+
+function ImageWriter.decode2bpp(raw, width, height, transparent)
+  assertDimensions(raw, width, height, 2)
+  local image = love.image.newImageData(width, height)
+  local tilesPerRow = width / 8
+  for tile = 0, #raw / 16 - 1 do
+    local tileX = tile % tilesPerRow * 8
+    local tileY = math.floor(tile / tilesPerRow) * 8
+    for y = 0, 7 do
+      local low = raw[tile * 16 + y * 2 + 1]
+      local high = raw[tile * 16 + y * 2 + 2]
+      for x = 0, 7 do
+        local divisor = 2 ^ (7 - x)
+        local shade = math.floor(high / divisor) % 2 * 2
+          + math.floor(low / divisor) % 2
+        local color = SHADES[shade + 1]
+        local alpha = color[4]
+        if transparent and shade == 0 then alpha = 0 end
+        image:setPixel(tileX + x, tileY + y,
+          color[1], color[2], color[3], alpha)
+      end
+    end
+  end
+  return image
+end
+
+function ImageWriter.decode1bpp(raw, width, height, transparent)
+  assertDimensions(raw, width, height, 1)
+  local image = love.image.newImageData(width, height)
+  local tilesPerRow = width / 8
+  for tile = 0, #raw / 8 - 1 do
+    local tileX = tile % tilesPerRow * 8
+    local tileY = math.floor(tile / tilesPerRow) * 8
+    for y = 0, 7 do
+      local row = raw[tile * 8 + y + 1]
+      for x = 0, 7 do
+        local filled = math.floor(row / 2 ^ (7 - x)) % 2 ~= 0
+        local value = filled and 0 or 1
+        local alpha = 1
+        if transparent and not filled then alpha = 0 end
+        image:setPixel(tileX + x, tileY + y,
+          value, value, value, alpha)
+      end
+    end
+  end
+  return image
+end
+
+function ImageWriter.blank(width, height, r, g, b, a)
+  local image = love.image.newImageData(width, height)
+  image:mapPixel(function() return r or 0, g or 0, b or 0, a or 0 end)
+  return image
+end
+
+function ImageWriter.blit(target, source, targetX, targetY,
+    sourceX, sourceY, width, height, flipX)
+  sourceX, sourceY = sourceX or 0, sourceY or 0
+  width, height = width or source:getWidth(), height or source:getHeight()
+  for y = 0, height - 1 do
+    for x = 0, width - 1 do
+      local sampleX = flipX and sourceX + width - 1 - x or sourceX + x
+      target:setPixel(targetX + x, targetY + y,
+        source:getPixel(sampleX, sourceY + y))
+    end
+  end
+end
+
+function ImageWriter.matteColor0(image)
+  local width, height = image:getDimensions()
+  local queueX, queueY, head = {}, {}, 1
+  local seen = {}
+  local function add(x, y)
+    local key = y * width + x
+    if seen[key] then return end
+    local r, g, b, a = image:getPixel(x, y)
+    if r == 1 and g == 1 and b == 1 and a == 1 then
+      seen[key] = true
+      queueX[#queueX + 1], queueY[#queueY + 1] = x, y
+    end
+  end
+  for x = 0, width - 1 do add(x, 0); add(x, height - 1) end
+  for y = 0, height - 1 do add(0, y); add(width - 1, y) end
+  while head <= #queueX do
+    local x, y = queueX[head], queueY[head]
+    head = head + 1
+    image:setPixel(x, y, 1, 1, 1, 0)
+    if x > 0 then add(x - 1, y) end
+    if x + 1 < width then add(x + 1, y) end
+    if y > 0 then add(x, y - 1) end
+    if y + 1 < height then add(x, y + 1) end
+  end
+  return image
+end
+
+function ImageWriter.columnsToRows(raw, tilesWide, tilesHigh, bytesPerTile)
+  bytesPerTile = bytesPerTile or 16
+  local out = {}
+  for y = 0, tilesHigh - 1 do
+    for x = 0, tilesWide - 1 do
+      local source = (x * tilesHigh + y) * bytesPerTile
+      local target = (y * tilesWide + x) * bytesPerTile
+      for offset = 1, bytesPerTile do
+        out[target + offset] = raw[source + offset]
+      end
+    end
+  end
+  return out
+end
+
+function ImageWriter.save(image, path)
+  local parent = path:match("^(.*)/[^/]+$")
+  if parent then
+    local ok, err = love.filesystem.createDirectory(parent)
+    if not ok then error("could not create " .. parent .. ": " .. tostring(err)) end
+  end
+  local ok, fileData = pcall(image.encode, image, "png")
+  if not ok then error("could not encode " .. path .. ": " .. tostring(fileData)) end
+  local written, writeError = love.filesystem.write(path, fileData)
+  if not written then
+    error("could not write " .. path .. ": " .. tostring(writeError))
+  end
+  return fileData
+end
+
+return ImageWriter