Fix partial refresh of displayio.TileGrid

[t-ikegami]

This PR fixes a partial refresh of displayio.TileGrid. The original code works only for limited combinations of DISPLAY.rotation and TileGrid.{flip_x, flip_y, transpose_xy}. The following is a test code to check the algorithm (tested on Wio Terminal).

import board
import time
import displayio as dpio
import bitmaptools as bmt

disp = board.DISPLAY
bmp = dpio.Bitmap(200, 150, 2)
pal = dpio.Palette(2)
pal[0] = 0xFFFFFF
pal[1] = 0x0000FF
tg = dpio.TileGrid(bmp, pixel_shader = pal)
g = dpio.Group()
g.append(tg)
disp.show(g)

tg.x = 20
tg.y = 10

def draw() :
  bmp.fill(0)
  disp.refresh()
  bmt.fill_region(bmp, 110, 10, 190, 60, 1)
  disp.refresh()
  time.sleep(1)

def do_test() :
  tg.flip_x = tg.flip_y = tg.transpose_xy = False
  draw()    # top right

  tg.flip_x = True
  draw()    # top left

  tg.flip_y = True
  draw()    # bottom left

  tg.transpose_xy = True
  draw()    # top right

  tg.flip_x = False
  draw()    # bottom right

  tg.flip_y = False
  draw()    # bottom left

  tg.transpose_xy = False
  draw()    # top right

disp.auto_refresh = False

disp.rotation = 0
do_test()

disp.rotation = 90
do_test()

disp.rotation = 180
do_test()

disp.rotation = 270
do_test()

disp.rotation = 0
disp.auto_refresh = True

[tannewt]

Thank you!