Draws a single pixel of an pixmap on the current context at x, y.
The color of the pixel comes from the pixmap as if p was tiled over the entrire context starting with the top/left of the
pixmap at x0, y0.
| x0 |
the alignment X coordinate |
| y0 |
the alignment Y coordinate |
| x |
the X coordinate |
| y |
the Y coordinate |
| p |
the pixmap |