[DataGrid] Fix white blank when scrolling

[alexfauquette]

Fix #3436

The problem is the following: To know when the rendered context must be updated, it relies on the top-left cell. If the index of the cell has changed by more than rowThreshold or columnThreshold, the renderContext is updated, which will rerender visible rows/cells and their buffer
This would work if columns/rows have the same size, which is not the case. Here is an example of scrolling on the right.

In purple you have the initial render context and in blue the buffer. From top to bottom we scrolled enough, such that

• the visible left cell changed from 3 to 4 (a gap of 1)
• the visible right cell changed from 5 to 8 (a gap of 3)

To be sure that visible columns are always rendered, we need to increase verify on the left and the right (same thing for the top/bottom)

[mui-bot]

These are the results for the performance tests:

Test case	Unit	Min	Max	Median	Mean	σ
Filter 100k rows	ms	252	529.3	422.9	387.3	104.206
Sort 100k rows	ms	515.2	975.3	825.3	797.86	157.627
Select 100k rows	ms	128.9	206.5	199.2	179.38	30.542
Deselect 100k rows	ms	107.6	278.8	193.3	186.42	56.775

Generated by 🚫 dangerJS against 9a698a8

[m4theushw]

Great illustration. It seems to solve the problem. 👍