24. Convert bitmap to level 256 grayscale

Gray value equals to R/3 + G/3 + B/3

Change the corresponding R, G, and B values to the above results and continue to display and store them in the true color bitmap format.

You can also use a color palette to display and store data.

 

Some people say that the brightness is calculated by using the formula Y = 0.11 * r + 0.59 * g + 0.39 * B. The corresponding R, G, and B values are changed to the above result, however, the actual test results show that the conversion is not feasible. In some cases, the results are all black. Of course, this is not the case.