63 lines
1.8 KiB
Lua
63 lines
1.8 KiB
Lua
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local function load(path)
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local image = { w = 0, h = 0, scale = 1.0, palette = {}, lines = {} }
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local fp, err = io.open(path, "rb")
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if not fp then return nil, err end
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local magic = fp:read(4)
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if magic ~= "CCPI" then
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return nil, "Invalid header: expected CCPI got " .. magic
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end
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image.w, image.h = string.byte(fp:read(1)), string.byte(fp:read(1))
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image.scale = 0.5 + string.byte(fp:read(1)) * 5 / 255
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for i = 1, 16 do
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image.palette[i] = bit.blshift(string.byte(fp:read(1)), 16)
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image.palette[i] = bit.bor(image.palette[i], bit.blshift(string.byte(fp:read(1)), 8))
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image.palette[i] = bit.bor(image.palette[i], string.byte(fp:read(1)))
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end
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for y = 1, image.h do
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local line = { s = "", bg = "", fg = "" }
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for x = 1, image.w do
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line.s = line.s .. fp:read(1)
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local char = fp:read(1)
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if char == nil then
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return nil, string.format("Failed to read color data for x=%d y=%d", x, y)
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end
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local color = string.byte(char)
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line.bg = line.bg .. string.format("%x", bit.band(0xF, color))
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line.fg = line.fg .. string.format("%x", bit.band(0xF, bit.brshift(color, 4)))
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end
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table.insert(image.lines, line)
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end
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fp:close()
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return image
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end
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local function draw(img, ox, oy, monitor)
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-- todo: add expect()
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local t = monitor or term.current()
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ox = ox or 1
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oy = oy or 1
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for i = 1, 16 do
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t.setPaletteColor(bit.blshift(1, i - 1), img.palette[i])
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end
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t.setTextScale(img.scale)
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for y = 1, img.h do
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t.setCursorPos(ox, oy + y - 1)
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t.blit(img.lines[y].s, img.lines[y].fg, img.lines[y].bg)
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end
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end
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return {
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load = load,
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draw = draw
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}
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