Selas | Offline renderer used for my blog posts | Blog library

Finally I figured it out. Now I am able to move the window without any flickering to the image I rendered as background. The problem was in two places in my code.

• GetWindowRect(): In WM_MOVING I was using GetWindowRect() to get the window Rectangle, this causes delay to obtain the window Rectangle and caused the flickering issue. The Solution I found was simple, I Converted the lParm to RECT by typecasting and using it as the value to update the location solved the issue. The code I used to solve the issue is given below :

RECT *hostRect = reinterpret_cast(lParam)

• MagSetWindowSource(): This is an interesting thing. I Don't know what is the use of magnifier in this. The code will not remove the flicker until I call MagSetWindowSource() function, I don't know why it is required, that alone consumes more memory in my program. if I removed this line of code it again starts to flicker. The input to the function doesn't matter you just have to call the function that's it.

Updated :

Finally figured out what is MagSetWindowSource() is doing, it actually calls a DWM function called DwmFlush() which Issues a flush call that blocks the caller until the next present. and that solved my issue. now it is flickerless and smooth.

Here is the fully updated code: