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Hi,
I could not find an appropriate tag for my problem so I selected the one I felt was most likely to give me relevant response.
I am currently working with an application in which it is extremely important that no copies of any data is retained in memory. This also include images that we obtain through a camara. We need to display those images to the user but must make sure that all traces of the image data is gone after we are done with it. We therefore are considering using SetDIBitsToDevice() to display the image in a win32 window.
Our main concern at the moment is how SetDIBitsToDevice() actually perform this process and what buffers it creates for this process and what happens to the content of those buffers after a call. Any help on this subject would be greatly appreciated
SetDIBitsToDevice allocates buffers for lpvBits and lpbmi with RtlAllocateHeap and free them with RtlFreeHeap
(when memory is not freed, MSDN usually adds "The caller is responsible for freeing the memory allocated...")
Thank you for that answer. I suspected that something like that was going on, but it is nice to have it confirmed.
Thank you very much
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(211.20000000000002, 61%, 30%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EBS%3C/text%3E%3C/svg%3E)
the implementation is up to the video device driver. but in the end the image is copied to video frame buffer and the winapi allows a program to capture the frame buffer contents. this is how screen snapshot programs work. an advanced user you use video drive traces to detailed info of what is sent to driver. There are also video drivers designed to capture video frames
your best bet is to watermark the images, so you can trace misuse..
note: if you control the group policies of the computers you can disable snapshot support. basically unless you control the hardware and software configuration of the devices, the user can get snapshots.
Thank you for that answer, but our specific problem is that we will be displaying a picture of the active user for a short while and we want to make sure that after we no longer display that image then there will be no trace of the image data in the system.
So we will provide the image data to SetDIBitsToDevice() and we want to make sure that we can clean it up after us. We have control over our own databuffers but not the ones used by SetDIBitsToDevice().
Currently, we do not need to worry about someone trying to make a copy of our active screen. Our problem is related to not leaving any traces (in memory) of the data that we have used.