Weak text when printing to Canvas [RESOLVED}

[simtrip]

I'm really not sure whether this is actually a bug or whether I'm overlooking something related to the love.graphics module, so I've posted here instead of the issue tracker. I've noticed that when printing text to a Canvas, text appears strangely weak or thin-looking compared to printing on the draw callback. Even stranger is that I've been able to fix the issue simply by drawing the same text to the Canvas again (literally copy-pasting the print line twice.)

Here it is exemplified in a GUI object I was working on - left is the image with 3 identical love.graphics.print() commands in a row drawn to a Canvas, and on the right is with just the one line.

2TgvZ.png (12.24 KiB) Viewed 206 times

The following code also creates the effect on my machine and a friend who tested his. The text from the Canvas appears less smooth than the text printed above it - any ideas why?

Code: Select all

function love.load()
	text = "Hello World"
	canvas = love.graphics.newCanvas()
	canvas:renderTo(function() love.graphics.print(text,1,1)end)
end

function love.update(dt)
end

function love.draw()
	love.graphics.print(text,10,10)
	love.graphics.draw(canvas,10,30)
end

Thanks!

[Xgoff]

you should set the blend mode to "premultiplied" before drawing a canvas that contains transparency (and set it back to "alpha" afterward)

[slime]

Use the "premultiplied" blend mode in place of the "alpha" blend mode when drawing the Canvas to the screen.

EDIT: ninja'd.

[simtrip]

Oh wow, excellent. So the effect is that love.graphics tries to perform its colour blending on image data that already has it present.
Thanks a bunch