27 lines
749 B
Text
27 lines
749 B
Text
local canvas = require "canvas"
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local function line(c, x0, y0, x1, y1, col)
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local dx = math.abs(x1 - x0)
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local dy = math.abs(y1 - y0)
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local sx = (x0 < x1) ? 1 : -1
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local sy = (y0 < y1) ? 1 : -1
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local err = (dx > dy ? dx : - dy) // 2
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while true do
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c:set(x0, y0, col)
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if x0 == x1 and y0 == y1 then break end
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local e2 = err
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if e2 > -dx then
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err -= dy
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x0 += sx
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end
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if e2 < dy then
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err += dx
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y0 += sy
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end
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end
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end
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local c = canvas.new(400, 400)
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c:fill(0xffffff) -- white background
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line(c, 0, 0, 399, 399, 0x0000ff) -- draw a red diagonal
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io.contents("mybmp.bmp", c:tobmp()) -- save to a bitmap file
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