I’ve been an Aseprite user since 2018, but I’ve only just started trying my hand at scripting. I’ve dabbled in Lua in the past, and done a fair bit of development, but I’m struggling with the API documentation quite a bit. (For example, it took me about a day to figure out that if I want my image to appear on a layer, it’s not done in in anything to do with “sprite” “image” or “draw” it happens by associating the image with a cel.)
So now I’m having another issue that seems like it should be simple and commonly done, but I can’t seem to find any examples, and my workarounds aren’t working. I want to be able to combine multiple images (or pieces of multiple images specified by rectangular bounds) into a single image, and then assign that combined image to a cel.
I shouldn’t have any pixels of the two images overlapping, but I’m fine with one image overwriting some pixels of another anyway. How can I easily slap one image on top of another like this?
Finally, I got it working. Here’s what I needed to know: drawImage() completely overwrites pixels regardless of transparency (don’t be fooled by blendMode!), also if you want to construct a blank image, you need only specify width and height of the image, but that width and height are critical, because it’s not going to draw outside of those dimensions.
local layer1 = newSprite:newLayer()
layer1.name = "Frame 2"
local interimImage = Image(sourceImage) -- Only putting this here for the initialization
local sectionWidth = 19 -- Width
local x = 416 -- position of upper left corner of current version
local y = 31
local minHeight = 79
local maxHeight = 151
local outputImage = Image(sectionWidth,maxHeight) --initilization of Image space - must be big enough to hold whole thing
for i = 0, sectionWidth-1 do
interimImage = Image(sourceImage) --copy the original
interimImage:resize{size=Size(sectionWidth,minHeight+2*i)} --resize and cut an appropriate slice
outputImage:drawImage(Image(interimImage, Rectangle{i, 0, i+1, minHeight+2*i}), i, sectionWidth - i) --dump the slice in the appropriate spot, shifted down and right by the right amount
end
local cel1 = newSprite:newCel(layer1,1,outputImage, Point(x,y-sectionWidth)) --last part only works when slope is 1
This is all because I am making a first-person pixel art dungeon crawler using 2D sprites, and I wanted something to take a single tile and make a first pass at arranging it in all the possible configurations I would want. (I will go and clean them up later)
