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getBounds & Path2D - Gideros Forum

getBounds & Path2D

rrraptorrrraptor Member
edited December 4 in General questions
How Is getBounds works???
Im trying to create a 100x100 rectangle with 6px outline.

On the left: green rect is 100x100, the shape behind is Path2D (see "rect" function).
On the right: green rect uses getBounds for size and position, Path2D is the same.
I assume that the outside line must be 3 px, aswell as inside - 3px, but its 4.42px outside and 1.58px inside?


I tried to fix Path2D shape, but result is the same

I thougth that it happens because of line feather parameter, but it turns out that its completely ignored by getBounds().


Test code:
application:setBackgroundColor(0x323232)
function tf(text, x, y)
	local t = TextField.new(nil, text, "|")
	t:setScale(2)
	t:setTextColor(0xffffff)
	t:setPosition(x, y)
	stage:addChild(t)
end
function pixel_rect(w, h, c, a)
	local p = Pixel.new(c, a, w, h)
	return p
end
 
function rect(w, h, c, sw, sc)
	local p = Path2D.new()
	local cm = "MLLLLZ"
	cs = {0,0, w,0, w,h, 0,h, 0,0}
	p:setPath(cm, cs)
	p:setFillColor(c, 1)
	p:setLineColor(sc, 1)
	p:setLineThickness(sw, 0.3)
	return p
end
function rect_fixed(w, h, c, sw, sc)
	local p = Path2D.new()
	local cm = "MLLLLZ"
	local hsw = sw / 2
	cs = {hsw,hsw, w-hsw,hsw, w-hsw,h-hsw, hsw,h-hsw, hsw,hsw}
	p:setPath(cm, cs)
	p:setFillColor(c, 1)
	p:setLineColor(sc, 1)
	p:setLineThickness(sw, 0.3)
	return p
end
 
function bounds(shape, c, a)
	local p = shape:getParent()
	local x,y,w,h = shape:getBounds(p)
	local px = Pixel.new(c, a, w, h)
	px:setPosition(x, y)
	p:addChild(px)
	return px
end
 
local w, h, sw = 100, 100, 6
tf(string.format("Original size [%.2f, %.2f] Stroke width %.2f", w, h, sw), 10, 10)
 
local r1 = rect(w, h, 0x323232, sw, 0)
r1:setPosition(100, 100)
tf(string.format("logical size:\n[%.2f, %.2f]", w, h), r1:getX(), r1:getY() - 50)
stage:addChild(r1)
 
local r2 = pixel_rect(w, h, 0x00ff00, 0.5)
r2:setPosition(r1:getPosition())
stage:addChild(r2)
 
local r3 = rect(w, h, 0x323232, sw, 0)
r3:setPosition(300, 100)
stage:addChild(r3)
 
local r4 = bounds(r3, 0x00ff00, 0.5)
tf(string.format("getBounds:\n[%.2f, %.2f]", r4:getDimensions()), r3:getX(), r3:getY() - 50)
 
local r5 = rect_fixed(w, h, 0x323232, sw, 0)
r5:setPosition(100, 300)
tf("Lets make shape smaler", r5:getX(), r5:getY() - 20)
stage:addChild(r5)
 
local r6 = bounds(r5, 0x00ff00, 0.5)
tf(string.format("getBounds:\n[%.2f, %.2f]", r6:getDimensions()), r5:getX(), r5:getY() + 120)
454.png
271 x 192 - 2K
123.png
375 x 168 - 2K

Comments

  • hgy29hgy29 Maintainer
    Path2D bounds are computed from the vertices sent to the shaders. I think the behaviour you see is caused by the corners of the rect: gideros issue a triangle on each corner to render the line join, and that triangle goes beyond what you would expect.
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