update logic for displayio.TileGrid's transform_xy

[kmatch98]

This resolves an error in redrawing when using transform_xy with displayio.TileGrid, referenced in issue #4450.

The logic for displayio_tilegrid_get_refresh_areas did not consider the TileGrid's transform_xy value and the transform of dirty rectangles was not being performed.

Here is the result with version Adafruit CircuitPython 6.2.0-beta.4 on 2021-03-18; Adafruit PyPortal with samd51j20:

Here is the result with the updated code in this PR:

Here is my test code:

import displayio
import board
import time
import math
import gc
from bitmaptools import rotozoom, fill_region
import adafruit_imageload
from _pixelbuf import colorwheel

delay_time=1

display=board.DISPLAY

bmap1 = displayio.Bitmap(150,200, 4)
palette1=displayio.Palette(4)
#palette1.make_transparent(3)
palette1[0]=0xFF0000
palette1[1]=0x00FF00
palette1[2]=0x0000FF
palette1[3]=0x00FFFF

tilegrid1=displayio.TileGrid(bmap1, pixel_shader=palette1)

group1=displayio.Group(max_size=1)
group1.x=20
group1.y=20

#group1.append(tilegrid0)
group1.append(tilegrid1)
display.show(group1)
time.sleep(delay_time)

print('1 change fill color of bitmap to blue')
bmap1.fill(2)
time.sleep(delay_time)

tilegrid1.transpose_xy=True
#tilegrid1.flip_x=True
#tilegrid1.flip_y=True

print('2 write red and light blue into two corners')

for i in range(bmap1.width//2):
    for j in range(bmap1.height//2):
        #print("i,j: {},{}".format(i,j))
        #time.sleep(0.001)
        bmap1[i,j]=0
        bmap1[bmap1.width-i-1, bmap1.height-j-1]=3

print('3 just finished')

time.sleep(10000)

[tannewt]

Thank you!