Fixed macro definition bug in mouse_c.h

[xuehaonan27]

Please provide Issues links to:

• Issues: screengrab_c.h has pointer implicit conversion behavior which will trigger warning. #696

Provide test code:

No test code needed.

Description

screengrab_c.h has a pointer implicit conversion behavior at line 93 (from void* to uint8_t *).
I added an explicit conversion to it.

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All committers have signed the CLA.

[xuehaonan27]

I found a new bug in mouse_c.h.
In line 101 definition of macro MOUSE_COORD_TO_ABS:

#define MOUSE_COORD_TO_ABS(coord, width_or_height) ( \
	((65536 * coord) / width_or_height) + (coord < 0 ? -1 : 1))

It's obvious that coord and width_or_height are not wrapped by brackets.
But follow code:

int32_t x = MOUSE_COORD_TO_ABS(point.x - rect.origin.x, rect.size.w);
int32_t y = MOUSE_COORD_TO_ABS(point.y - rect.origin.y, rect.size.h);

The desired behavior is 65536 * (point.x - rect.origin.x).
But actually it's 65536 * point.x - rect.origin.x.
It's a big bug that would lead to mouse position problem as mentioned in issue #479 and issue #631 .

I don't know whether my fix could solve them completely, but it's definitely a big step forward.

[xuehaonan27]

Would you review this PR soon? @vcaesar

[PekingSpades]

Very helpful for my project