Blits are zoomed as if their center is the top-left corner and not center of image

[bferguson3]

This is difficult to explain so bear with me -

If you blit a 10x10 square onto 0,0, it will cover the span of (0 to 10, 0 to 10).

If you blit that square with a zoom of 2, if will cover the span of (-10 to 10, 0 to 20).

There is no way of blitting an image to a specific xy dimensions unless you know the exact dimensions, in units of the size/scale of image you are blitting, and without performing extra manipulative x math to get it in the right position.

The ideal behavior here would be the x,y position you define in the function parameter is always the top-left corner - OR, an additional blt() definition where you can specify the exact dimensions, which afaik is how it is rendered behind the scenes anyway.

[squiddy]

I agree, I'm currently having a helper function to help me blt always in the top-left corner.

Small example just to visualize the behaviour.

# /// script
# dependencies = [
#   "pyxel",
# ]
# ///

import pyxel

pyxel.init(100, 100)

pyxel.images[0].set(0, 0, ["3"*10]*10)
pyxel.blt(10, 10, 0, 0, 0, 10, 10, 0, scale=1)
pyxel.blt(10, 50, 0, 0, 0, 10, 10, 0, scale=2)
pyxel.blt(50, 50, 0, 0, 0, 10, 10, 0, scale=3)

# grid
for y in range(10, pyxel.height, 10):
    for x in range(10, pyxel.width, 10):
        pyxel.pset(x, y, 13)

# blt positions
pyxel.pset(10, 10, 8)
pyxel.pset(10, 50, 8)
pyxel.pset(50, 50, 8)

pyxel.show()