I'm trying to do some pixel art, and whenever I use a tool that isn't just the pencil tool, it makes its own weird shading along my selection. Like, if I make a diagonal line with black, fills in random gray above and below the line between the two points I click. Or if I make a non filled circle, it fills in shading around the edges. All this is with one pixel thickness How do I just make it the color I've picked from the color picker without any extra color interpolations along the way?