Mosaic: fix inconsistently drawn keyboard cursor.

Every call to draw_cell() was drawing a region including the whole
border of the cell, so that the calls overlapped. So if the cursor
moved left or up, then a COL_CURSOR outline would be drawn around the
new cell, and then a COL_GRID outline would be drawn around the old
cell, overwriting part of the cursor border.

I've fixed this in the rigorous way, by making draw_cell() calls cover
disjoint areas of the puzzle canvas, and using clip() to enforce that.
So now the single DRAWFLAG_CURSOR is replaced by a system of four
flags, indicating that the cell being drawn is the actual cursor
position, or the cell below it (hence containing the cursor's bottom
border), or to its right (needing the left border), or below _and_ to
the right (you still need the single pixel at the cursor's bottom
right corner!).

Also, to ensure the cursor edges are drawn even on the bottom or right
grid boundaries, draw_cell() is called for a set of virtual cells
beyond the actual grid bounds, with additional flags telling it not to
draw an actual puzzle cell there, just the relevant pieces of border.

0 files changed, 0 insertions, 0 deletions