skia2/tools/lua/skia.lua

92 lines
1.8 KiB
Lua

-- Experimental helpers for skia --
function string.startsWith(String,Start)
return string.sub(String,1,string.len(Start))==Start
end
function string.endsWith(String,End)
return End=='' or string.sub(String,-string.len(End))==End
end
Sk = {}
function Sk.isFinite(x)
return x * 0 == 0
end
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Sk.Rect = { left = 0, top = 0, right = 0, bottom = 0 }
Sk.Rect.__index = Sk.Rect
function Sk.Rect.new(l, t, r, b)
local rect
if r then
-- 4 arguments
rect = { left = l, top = t, right = r, bottom = b }
elseif l then
-- 2 arguments
rect = { right = l, bottom = t }
else
-- 0 arguments
rect = {}
end
setmetatable(rect, Sk.Rect)
return rect;
end
function Sk.Rect:width()
return self.right - self.left
end
function Sk.Rect:height()
return self.bottom - self.top
end
function Sk.Rect:isEmpty()
return self:width() <= 0 or self:height() <= 0
end
function Sk.Rect:isFinite()
local value = self.left * 0
value = value * self.top
value = value * self.right
value = value * self.bottom
return 0 == value
end
function Sk.Rect:setEmpty()
self.left = 0
self.top = 0
self.right = 0
self.bottom = 0
end
function Sk.Rect:set(l, t, r, b)
self.left = l
self.top = t
self.right = r
self.bottom = b
end
function Sk.Rect:offset(dx, dy)
dy = dy or dx
self.left = self.left + dx
self.top = self.top + dy
self.right = self.right + dx
self.bottom = self.bottom + dy
end
function Sk.Rect:inset(dx, dy)
dy = dy or dx
self.left = self.left + dx
self.top = self.top + dy
self.right = self.right - dx
self.bottom = self.bottom - dy
end
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