Development of the program

Requires development of a program to implement the below scenario.

The input is a raster or a vector image, done in grayscale. (The program should accept the formats .cdr .ai .pdf, .jpg)
This image is broken/redrawn on the same vector squares. The size of the square is set manually. (basic working dimensions of the squares from 0.001 mm to 0.1 mm. the Step of specifying the size of the squares should be 0.001 mm)
For each square must be calculated and attributed the average shade of gray.
Should be the choice for extreme/side squares (to cut/to trim/extend).
The output should have a file that is understandable to CorelDRAW without distortion of size, geometry or colors.

The main task is the speed of building the squares.
At the moment there is a macro for CorelDRAW, which does breakdown into squares and calculate the average shade of gray, but his main problem is very long (split into squares of 0.01 mm x 0.01 mm small drawing 20 mm x 5 mm is of the order of 6-12 hours). We are interested in processing about the same size image at 30 minutes, but if it is possible and much faster). This macro can provide for a more detailed understanding of the job.
The program should work in Windows 7, 8, 8.1 (working in Windows 10 is not mandatory, but desirable)